A SYSTEM OF INSTRUCTION IN THE PRACTICAL USE OF THE BLOWPIPE. 

 BEING A GRADUATED COURSE OF ANALYSIS FOR THE USE OF STUDENTS AND ALL THOSE ENGAGED IN THE EXAMINATION OF METALLIC COMBINATIONS. 

 NEW YORK: H. BAILLIÈRE, 290 BROADWAY, AND 219 REGENT STREET, LONDON. 

 PARIS: J. B. BAILLIÈRE ET FILS, RUE HAUTEFEUILLE. MADRID: C. BAILLY-BAILLIÈRE, CALLE DEL PRINCIPE. 1858. 

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 ENTERED according to Act of Congress, in the year 1858, by C. E. BAILLIÈRE, In the Clerk's Office of the District Court of the United States, for the Southern District of New York. 

 W. H. TINSON, Printer and Stereotyper, 43 Centre Street. 

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TABLE OF CONTENTS. 

PART I. 

Preface, 7The Use of the Blowpipe, 9Utensils--The Blowpipe, 12The Oil Lamp, 22The Spirit Lamp, 23Charcoal Support, 24Platinum Supports, 26Iron Spoons, 28Glass Tubes, 28Other Apparatus necessary, 31THE REAGENTS, 34 Reagents of General Use, 34 Carbonate of Soda, 34 Hydrate of Baryta, 35 Bi-sulphate of Potassa, 35 Oxalate of Potassa, 36 Cyanide of Potassium, 36Nitrate of Potassa, 37 Borax, 38 Microcosmic Salt, 39 Nitrate of Cobalt, 40 Tin, 41 Silica, 42 Test Papers, 42ESPECIAL REAGENTS, 43 Boracic Acid, 43 Fluorspar, 43 Oxalate of Nickel, 43 Oxide of Copper, 43 Antimoniate of Potassa, 44 Silver Foil, 44 Nitroprusside of Sodium, 44

PART II. 

Initiatory Analysis, 47Examination with the Glass Bulb, 47 " in the Open Tube, 52 " upon Charcoal, 55 " in the Platinum Forceps, 61 " in the Borax Bead, 69 " in Microcosmic Salt, 72Table I. --Colors of Beads of Borax and Microcosmic Salt, 75Table II. --Behavior of Metallic Oxydes with Borax and Microcosmic Salt, 85Examinations with Carbonate of Soda, 103

PART III. 

Special Reactions, 109A. --METALLIC OXIDES: First Group. --The Alkalies: Potassa, Soda, Ammonia, and Lithia, 110 Second Group. --The Alkaline Earths: Baryta, Strontia, Lime, and Magnesia, 115 Third Group. --The Earths: Alumina, Glucina, Yttria, Thorina, and Zirconia, 121 Fourth Group. --Cerium, Lanthanium, Didymium, Columbium, Niobium, Pelopium, Titanium, Uranium, Vanadium, Chromium, Manganese, 124 Fifth Group. --Iron, Cobalt, Nickel, 135 Sixth Group. --Zinc, Cadmium, Antimony, Tellurium, 140 Seventh Group. --Lead, Bismuth, Tin, 149 Eighth Group. --Mercury, Arsenic, 157 Ninth Group. --Copper, Silver, Gold, 161 Tenth Group. --Molybdenum, Osmium, 165 Eleventh Group. --Platinum, Palladium, Iridium, Rhodium, Ruthenium, 167

Non-Metallic Substances, 168

Tabular Statement of the Reactions of Minerals before the Blowpipe, 178 Carbon and Organic Minerals, 181 Potassa, 184 Soda, 186 Baryta and Strontia, 190 Lime, 192 Magnesia, 196 Alumina, 200 Silicates, 204 Uranium, 212 Iron, 214 Manganese, 222 Nickel and Cobalt, 226 Zinc, 232 Bismuth, 234 Lead, 238 Copper, 248 Antimony, 256 Arsenic, 260 Mercury, 262 Silver, 264

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PREFACE. 

It is believed the arrangement of the present work is superior to thatof many of its predecessors, as a vehicle for the facilitation of thestudent's progress. While it does not pretend to any other rank thanas an introduction to the larger works, it is hoped that thearrangement of its matter is such that the beginner may more readilycomprehend the entire subject of Blowpipe Analysis than if he were tobegin his studies by the perusal of the more copious works ofBerzelius and Plattner. 

When the student shall have gone through these pages, and repeated thevarious reactions described, then he will be fully prepared to enterupon the study of the larger works. To progress through them will thenbe but a comparatively easy task. 

The arrangement of this little work has been such as the author andhis friends have considered the best that could be devised for thepurpose of facilitating the progress of the student. Whether we havesucceeded is left for the public to decide. The author is indebted toseveral of his friends for valuable contributions and suggestions. 

S. 

CINCINNATI, _June, 1857_. 

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 THE BLOWPIPE. 

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Part First. 

THE USE OF THE BLOWPIPE. 

Perhaps during the last fifty years, no department of chemistry hasbeen so enriched as that relating to analysis by means of theBlowpipe. 

Through the unwearied exertions of men of science, the use of thisinstrument has arrived to such a degree of perfection, that we have aright to term its use, "Analysis in the _dry_ way, " in contradistinctionto analysis "in the _wet_ way. " The manipulations are so simple andexpeditious, and the results so clear and characteristic, that theBlowpipe analysis not only verifies and completes the results ofanalysis in the wet way, but it gives in many cases direct evidencesof the presence or absence of many substances, which would not beotherwise detected, but through a troublesome and tedious process, involving both prolixity and time; for instance, the detection ofmanganese in minerals. 

Many substances have to go through Blowpipe manipulations before theycan be submitted to an analysis in the wet way. The apparatus andreagents employed are compendious and small in number, so that theycan be carried easily while on scientific excursions, a considerableadvantage for mineralogists and metallurgists. 

The principal operations with the Blowpipe may be explained briefly asfollows:

(_a. _) By _Ignition_ is meant the exposure of a substance to such adegree of heat, that it glows or emits light, or becomes red-hot. Itsgreatest value is in the separation of a volatile substance from oneless volatile, or one which is entirely fixed at the temperature ofthe flame. In this case we only take cognizance of the latter or fixedsubstance, although in many instances we make use of ignition for thepurpose of changing the conditions of a substance, for example, thesesquioxide of chromium (Cr^{2}O^{3}) in its insoluble modification;and as a preliminary examination for the purpose of ascertainingwhether the subject of inquiry be a combination of an organic orinorganic nature. 

The apparatus used for this purpose are crucibles of platinum orsilver, platinum foil, a platinum spoon, platinum wire or tongs, charcoal, glass tubes, and iron spoons. 

(_b. _) _Sublimation_ is that process by which we convert a solidsubstance into vapor by means of a strong heat. These vapors arecondensed by refrigeration into the solid form. It may be termed adistillation of a solid substance. Sublimation is of great consequencein the detection of many substances; for instance, arsenic, antimony, mercury, etc. 

The apparatus used for the purposes of sublimation consist of glasstubes closed at one end. 

(_c. _) _Fusion. _--Many substances when exposed to a certain degree ofheat lose their solid form, and are converted into a liquid. Thosesubstances which do not become converted into the liquid state byheat, are said to be infusible. It is a convenient classification toarrange substances into those which are fusible with difficulty, andthose which are easily fusible. Very often we resort to fusion for thepurpose of decomposing a substance, or to cause it to enter intoother combinations, by which means it is the more readily detected. Ifinsoluble substances are fused with others more fusible (reagents) forthe purpose of causing a combination which is soluble in water andacids, the operation is termed _unclosing_. These substances areparticularly the silicates and the sulphates of the alkaline earths. The usual reagents resorted to for this purpose are carbonate of soda(NaO, CO^{2}), carbonate of potash (KO, CO^{2}), or still better, amixture of the two in equal parts. In some cases we use the hydrate ofbarytes (BaO, HO) and the bisulphate of potash (KO, 2SO^{3}). Theplatinum spoon is generally used for this manipulation. 

Substances are exposed to fusion for the purpose of getting a newcombination which has such distinctive characteristics that we canclass it under a certain group; or for the purpose of ascertaining atonce what the substance may be. The reagents used for this purpose areborax (NaO, 2BrO^{3}) and the microcosmic salt (NaO, NH^{4}O, PO^{5}, HO). Charcoal and the platinum wire are used as supports for this kindof operation. 

(_d. _) _Oxidation. _--The chemical combination of any substance withoxygen is termed _oxidation_, and the products are termed _oxides_. Asthese oxides have qualities differing from those which arenon-oxidized, it therefore frequently becomes necessary to convertsubstances into oxides; or, if they are such, of a lower degree, toconvert them into a higher degree of oxidation. These different statesof oxidation frequently present characteristic marks of identitysufficient to enable us to draw conclusions in relation to thesubstance under examination. For instance, the oxidation of manganese, of arsenic, etc. The conditions necessary for oxidation, are hightemperature and the free admission of air to the substance. 

If the oxidation is effected through the addition of a substancecontaining oxygen (for instance, the nitrate or chlorate of potash)and the heating is accompanied by a lively deflagration and cracklingnoise, it is termed _detonation_. By this process we frequentlyeffect the oxidation of a substance, and thus we prove the presence orthe absence of a certain class of substances. For instance, if wedetonate (as it is termed by the German chemists) the sulphide ofantimony, or the sulphide of arsenic with nitrate of potash, we getthe nitrate of antimony, or the nitrate of arsenic. The salts ofnitric or chloric acid are determined by fusing them with the cyanideof potassium, because the salts of these acids detonate. 

(_e. _) _Reduction. _--If we deprive an oxidized substance of itsoxygen, we term the process _reduction_. This is effected by fusingthe substance under examination with another which possesses a greateraffinity for oxygen. The agents used for reduction are hydrogen, charcoal, soda, cyanide of potassium, etc. Substances generally, whenin the unoxidized state, have such characteristic qualities, that theycannot very readily be mistaken for others. For this reason, reductionis a very excellent expedient for the purpose of discerning andclassifying many substances. 

B. UTENSILS. 

We shall give here a brief description of the most necessary apparatusused for analysis in the dry way, and of their use. 

_The Blowpipe_ is a small instrument, made generally out of brass, silver, or German silver, and was principally used in earlier timesfor the purpose of soldering small pieces of metals together. It isgenerally made in the form of a tube, bent at a right angle, butwithout a sharp corner. The largest one is about seven inches long, and the smallest about two inches. The latter one terminates with asmall point, with a small orifice. The first use of the blowpipe thatwe have recorded is that of a Swedish mining officer, who used it inthe year 1738 for chemical purposes, but we have the most meagreaccounts of his operations. In 1758 another Swedish mining officer, bythe name of Cronstedt, published his "Use of the Blowpipe inChemistry and Mineralogy, " translated into English, in 1770, by VanEngestroem. Bergman extended its use, and after him Ghan and thevenerable Berzelius (1821). The blowpipe most generally used inchemical examinations is composed of the following parts: (_Fig. _ 1. )A is a little reservoir made air-tight by grinding the part B into it. This reservoir serves the purpose of retaining the moisture with whichthe air from the mouth is charged. A small conical tube is fitted tothis reservoir. This tube terminates in a fine orifice. As this smallpoint is liable to get clogged up with soot, etc. , it is better thatit should be made of platinum, so that it may be ignited. Two of theseplatinum tubes should be supplied, differing in the size of theorifice, by which a stronger or lighter current of flame may beprojected from it. Metals, such as brass or German silver, are veryliable to become dirty through oxidation, and when placed between thelips are liable to impart a disagreeable taste. To avoid this, the topof the tube must be supplied with a mouthpiece of ivory or horn C. Theblowpipe here represented is the one used by Ghan, and approved byBerzelius. The trumpet mouthpiece was adopted by Plattner; it ispressed upon the lips while blowing, which is less tiresome thanholding the mouthpiece between the lips, although many prefer thelatter mode. 

[Illustration: Fig. 1]

Dr. Black's blowpipe is as good an instrument and cheaper. Itconsists of two tubes, soldered at a right angle; the larger one, intowhich the air is blown, is of sufficient capacity to serve as areservoir. 

A chemist can, with a blowpipe and a piece of charcoal, determine manysubstances without any reagents, thus enabling him, even whentravelling, to make useful investigations with means which are alwaysat his disposal. There are pocket blowpipes as portable as a pencilcase, such as Wollaston's and Mitscherlich's; these are objectionablefor continued use as their construction requires the use of a metallicmouthpiece. Mr. Casamajor, of New York, has made one lately which hasan ivory mouthpiece, and which, when in use, is like Dr. Black's. 

[Illustration: Fig. 2]

The length of the blowpipe is generally seven or eight inches, butthis depends very much upon the visual angle of the operators. Ashort-sighted person, of course, would require an instrument of lesslength than would suit a far-sighted person. 

The purpose required of the blowpipe is to introduce a fine current ofair into the flame of a candle or lamp, by which a higher degree ofheat is induced, and consequently combustion is more rapidlyaccomplished. 

By inspecting the flame of a candle burning under usual circumstances, we perceive at the bottom of the flame a portion which is of a lightblue color (_a b_), _Fig. _ 2, which gradually diminishes in sizeas it recedes from the wick, and disappears when it reaches theperpendicular side of the flame. In the midst of the flame there is adark nucleus with a conical form (_c_). This is enveloped by theilluminating portion of the flame (_d_). At the exterior edge of thepart _d_ we perceive a thin, scarcely visible veil, _a, e, e_, whichis broader near the apex of the flame. The action of the burningcandle may be thus explained. The radiant heat from the flame meltsthe tallow or wax, which then passes up into the texture of the wickby capillary attraction until it reaches the glowing wick, where theheat decomposes the combustible matter into carbonated hydrogen(C^{4}H^{4}), and into carbonic oxide (CO). 

While these gases are rising in hot condition, the air comes incontact with them and effects their combustion. The dark portion, _c_, of the flame is where the carbon and gases have not a sufficiency ofair for their thorough combustion; but gradually they become mixedwith air, although not then sufficient for complete combustion. Thehydrogen is first oxidized or burnt, and then the carbon is attackedby the air, although particles of carbon are separated, and it isthese, in a state of intense ignition, which produce the illumination. By bringing any oxidizable substance into this portion of the flame, it oxidizes very quickly in consequence of the high temperature andthe free access of air. For that reason this part of the flame istermed the oxidizing flame, while the illuminating portion, by itstendency to abstract oxygen for the purpose of complete combustion, easily reduces oxidated substances brought into it, and it is, therefore, called the flame of reduction. In the oxidizing flame, onthe contrary, all the carbon which exists in the interior of the flameis oxidized into carbonic acid (CO^{2}) and carbonic oxide (CO), whilethe blue color of the cone of the flame is caused by the completecombustion of the carbonic oxide. These two portions of the flame--theoxidizing and the reducing--are the principal agents of blowpipeanalysis. 

If we introduce a fine current of air into a flame, we notice thefollowing: The air strikes first the dark nucleus, and forcing thegases beyond it, mixes with them, by which oxygen is mingled freelywith them. This effects the complete combustion of the gases at acertain distance from the point of the blowpipe. At this place theflame has the highest temperature, forming there the point of a bluecone. The illuminated or reducing portion of the flame is envelopedoutside and inside by a very hot flame, whereby its own temperature isso much increased that in this reduction-flame many substances willundergo fusion which would prove perfectly refractory in a commonflame. The exterior scarcely visible part loses its form, isdiminished, and pressed more to a point, by which its heating power isgreatly increased. 

_The Blast of Air. _--By using the blowpipe for chemical purposes, theeffect intended to be produced is an uninterrupted steady stream ofair for many minutes together, if necessary, without an instant'scessation. Therefore, the blowing can only be effected with themuscles of the cheeks, and not by the exertion of the lungs. It isonly by this means that a steady constant stream of air can be keptup, while the lungs will not be injured by the deprival of air. Thedetails of the proper manner of using the blowpipe are really moredifficult to describe than to acquire by practice; therefore the pupilis requested to apply himself at once to its practice, by which hewill soon learn to produce a steady current of air, and to distinguishthe different flames from each other. We would simply say that thetongue must be applied to the roof of the mouth, so as to interruptthe communication between the passage of the nostrils and the mouth. The operator now fills his mouth with air, which is to be passedthrough the pipe by compressing the muscles of the cheeks, while hebreathes through the nostrils, and uses the palate as a valve. Whenthe mouth becomes nearly empty, it is replenished by the lungs in aninstant, while the tongue is momentarily withdrawn from the roof ofthe mouth. The stream of air can be continued for a long time, withoutthe least fatigue or injury to the lungs. The easiest way for thestudent to accustom himself to the use of the blowpipe, is first tolearn to fill the mouth with air, and while the lips are kept firmlyclosed to breathe freely through the nostrils. Having effected thismuch, he may introduce the mouthpiece of the blowpipe between hislips. By inflating the cheeks, and breathing through the nostrils, hewill soon learn to use the instrument without the least fatigue. Theair is forced through the tube against the flame by the action of themuscles of the cheeks, while he continues to breathe withoutinterruption through the nostrils. Having become acquainted with thisprocess, it only requires some practice to produce a steady jet offlame. A defect in the nature of the combustible used, as bad oil, such as fish oil, or oil thickened by long standing or by dirt, dirtycotton wick, or an untrimmed one, or a dirty wickholder, or a want ofsteadiness of the hand that holds the blowpipe, will prevent a steadyjet of flame. But frequently the fault lies in the orifice of the jet, or too small a hole, or its partial stoppage by dirt, which willprevent a steady jet of air, and lead to difficulty. With a goodblowpipe the air projects the entire flame, forming a horizontal, bluecone of flame, which converges to a point at about an inch from thewick, with a larger, longer, and more luminous flame enveloping it, and terminating to a point beyond that of the blue flame. 

To produce an efficient flame of oxidation, put the point of theblowpipe into the flame about one third the diameter of the wick, andabout one twelfth of an inch above it. This, however, depends uponthe size of the flame used. Blow strong enough to keep the flamestraight and horizontal, using the largest orifice for the purpose. Upon examining the flame thus produced, we will observe a long, blueflame, _a b_, Fig. 3, which letters correspond with the same lettersin Fig. 2. But this flame has changed its form, and contains all thecombustible gases. It forms now a thin, blue cone, which converges toa point about an inch from the wick. This point of the flame possessesthe highest intensity of temperature, for there the combustion of thegases is the most complete. In the original flame, the hottest partforms the external envelope, but here it is compressed more into apoint, forming the cone of the blue flame, and likewise an envelope offlame surrounding the blue one, extending beyond it from _a_ to _c_, and presenting a light bluish or brownish color. The external flamehas the highest temperature at _d_, but this decreases from _d_ to_c_. 

[Illustration: Fig. 3]

If there is a very high temperature, the oxidation is not effected soreadily in many cases, unless the substance is removed a little fromthe flame; but if the heat be not too high, it is readily oxidized inthe flame, or near its cone. If the current of air is blown toofreely or violently into the flame, more air is forced there than issufficient to consume the gases. This superfluous air only actsdetrimentally, by cooling the flame. 

In general the operation proceeds best when the substance is kept at adull red heat. The blue cone must be kept free from straggling rays ofthe yellow or reduction flame. If the analysis be effected oncharcoal, the blast should not be too strong, as a part of the coalwould be converted into carbonic oxide, which would actantagonistically to the oxidation. The oxidation flame requires asteady current of air, for the purpose of keeping the blue coneconstantly of the same length. For the purpose of acquiring practice, the following may be done: Melt a little molybdenic acid with someborax, upon a platinum wire, about the sixteenth of an inch from thepoint of the blue cone. In the pure oxidation flame, a clear yellowishglass is formed; but as soon as the reduction flame reaches it, or thepoint of the blue cone touches it, the color of the bead changes to abrown, which, finally, after a little longer blowing, becomes quitedark, and loses its transparency. The cause of this is, that themolybdenic acid is very easily reduced to a lower degree of oxidation, or to the oxide of molybdenum. The flame of oxidation will againconvert this oxide into the acid, and this conversion is a good testof the progress of the student in the use of the blowpipe. In caseswhere we have to separate a more oxidizable substance from a less one, we use with success the blue cone, particularly if we wish todetermine whether a substance has the quality, when submitted to heatin the blue cone, of coloring the external flame. 

A good _reduction_ flame can be obtained by the use of a small orificeat the point of the blowpipe. In order to produce such a flame, holdthe point of the blowpipe higher above the wick, while the nozzle mustnot enter the flame so far as in the production of the oxidationflame. The point of the blowpipe should only touch the flame, whilethe current of air blown into it must be stronger than into theoxidation flame. If we project a stream, in the manner mentioned, intothe flame, from the smaller side of the wick to the middle, we shallperceive the flame changed to a long, narrow, luminous cone, _a b_, Fig. 4, the end _a_ of which is enveloped by the same dimly visibleblueish colored portion of the flame _a, c_, which we perceive in theoriginal flame, with its point at _c_. The portion close above thewick, presenting the dull appearance, is occasioned by the risinggases which have not supplied to them enough oxygen to consume thementirely. The hydrogen is consumed, while the carbon is separated in astate of bright ignition, and forms the internal flame. 

[Illustration: Fig. 4]

Directly above the wick, the combustion of the gases is leastcomplete, and forms there likewise, as is the case in the free flame, a dark blue nucleus _d_. 

If the oxide of a metal is brought into the luminous portion of theflame produced as above, so that the flame envelopes the substanceperfectly, the access of air is prevented. The partially consumedgases have now a strong affinity for oxygen, under the influence ofthe intense heat of that part of the flame. The substance is thusdeprived of a part, or the whole, of its oxygen, and becomes _reduced_according to the strength of the affinity which the substance itselfhas for oxygen. If the reduction of a substance is undertaken onplatinum, by fusion with a flux, and if the oxide is difficult toreduce, the reduction will be completely effected only in the luminouspart of the flame. But if a substance be reduced on charcoal, thereduction will take place in the blue part of the flame, as long asthe access of air is cut off; but it is the luminous part of the flamewhich really possesses the greatest reducing power. 

The following should be observed in order to procure a good reductionflame:

 The wick should not be too long, that it may make a smoke, nor too short, otherwise the flame will be too small to produce a heat strong enough for reduction. 

 The wick must be free from all loose threads, and from charcoal. 

 The blast should be continued for a considerable time without intermission, otherwise reduction cannot be effected. 

For the purpose of acquiring practice, the student may fuse the oxideof manganese with borax, upon a platinum wire, in the oxidation flame, when a violet-red glass will be obtained; or if too much of the oxidebe used, a glass of a dark color and opaque will be obtained. Bysubmitting this glass to the reduction flame, it will become colorlessin correspondence to the perfection with which the flame is produced. Or a piece of tin may be fused upon charcoal, and kept in that statefor a considerable time, while it presents the appearance of a brightmetal on the surface. This will require dexterity in the operator;for, if the oxidation flame should chance to touch the bright metalonly for a moment, it is coated with an infusible oxide. 

COMBUSTION. --Any flame of sufficient size can be used for blowpipeoperations. It may be either the flame of a candle of tallow or wax, or the flame of a lamp. The flame of a wax candle, or of an oil lampis most generally used. Sometimes a lamp is used filled with asolution of spirits of turpentine in strong alcohol. If a candle isused, it is well to cut the wick off short, and to bend the wick alittle toward the substance experimented upon. But candles are not thebest for blowpipe operations, as the radiant heat, reflecting from thesubstance upon the wax or tallow, will cause it to melt and run downthe side of the candle; while again, candles do not give heat enough. The lamp is much the most desirable. The subjoined figure, fromBerzelius, is perhaps the best form of lamp. It is made of japannedtin-plate, about four inches in length, and has the form andarrangement represented in Fig. 5. K is the lamp, fastened on thestand, S, by a screw, C, and is movable upwards or downwards, asrepresented in the figure. The posterior end of the lamp may be aboutone inch square, and at its anterior end, E, about three-quarters ofan inch square. The under side of this box may be round, as seen inthe figure. The oil is poured into the orifice, A, which has a capscrewed over it. C' is a wickholder for a flat lamp-wick. _a_ is asocket containing the wick, which, when not in use, is secured fromdirt by the cap. The figures B and _a'_ give the forms of the cap andsocket. The best combustible for this lamp is the refined rape-seedoil, or pure sweet oil. When this lamp is in use, there must be noloose threads, or no charcoal on the wick, or these will produce asmoky flame. The wick, likewise, should not be pulled up too high, asthe same smoky flame would be produced. 

[Illustration: Fig. 5]

THE SPIRIT-LAMP. --This is a short, strong glass lamp, with a cap, B, Fig. 6, fitted to it by grinding, to prevent the evaporation of thealcohol. The neck _a_ contains a tube C, made of silver, or of tinplate, and which contains the wick. Brass would not answer so wellfor this tube, as the spirits would oxidize it, and thus impart colorto the flame. The wickholder must cover the edge of the neck, but notfit tight within the tube, otherwise, by its expansion, it will breakthe glass. It is not necessary that alcohol, very highly rectified, should be burnt in this lamp, although if too much diluted with water, enough heat will not be given out. Alcohol of specific gravity 0. 84 to0. 86 is the best. 

[Illustration: Fig. 6]

This lamp is generally resorted to by blowpipe analysts, for thepurpose of experiments in glass apparatus, as the oily combustibleswill coat the glass with soot. Some substances, when exposed to thedark part of the flame, become reduced and, _in statu nascendi_, evaporated; but by passing through the external part of the flame, they become oxidized again, and impart a color to the flame. Thespirit flame is the most efficient one for the examination ofsubstances the nature of which we wish to ascertain through colorimparted to the flame, as that of the spirit-lamp being colorless, is, consequently, most easily and thoroughly recognized by the slightesttinge imparted to it. 

It is necessary that in operating with such minute quantities ofsubstances as are used in blowpipe analysis, that they should havesome appropriate support. In order that no false results may ensue, itis necessary that the supports should be of such a nature that theywill not form a chemical combination with the substance while it isexposed to fusion or ignition. Appropriate supports for the differentblowpipe experiments are charcoal, platinum instruments, and glasstubes. 

(_a. _) _Charcoal. _--The value of charcoal as a support may be statedas follows:

 1. The charcoal is infusible, and being a poor conductor of heat, a substance can be exposed to a higher degree of heat upon it than upon any other substance. 

 2. It is very porous, and therefore allows easily fusible substances (such as alkalies and fluxes) to pass into it, while other substances less fusible, such as metals, to remain unabsorbed. 

 3. It has likewise a great reducing power. 

The best kind of charcoal is that of pinewood, linden, willow, oralderwood, or any other soft wood. Coal from the firwood sparkles toofreely, while that of the hard woods contains too much iron in itsashes. Smooth pieces, free from bark and knots, should be selected. Itshould be thoroughly burnt, and the annual rings or growths should beas close together as possible. 

If the charcoal is in masses, it should be sawed into pieces about sixinches in length by about two inches broad, but so that theyear-growths run perpendicular to the broadest side, as the othersides, by their unequal structure, burn unevenly. 

That the substance under examination may not be carried off by theblast, small conical concavities should be cut in the broad side ofthe charcoal, between the year-growths, with a conical tube of tinplate about two or three inches long, and one quarter of an inch atone end, and half an inch at the other. These edges are made sharpwith a file. The widest end of this charcoal borer is used for thepurpose of making cavities for cupellation. 

In places where the proper kind of charcoal is difficult to procure, it is economical to cut common charcoal into pieces about an inchbroad, and the third of an inch thick. In each of these little piecessmall cavities should be cut with the small end of the borer. Whenthese pieces of charcoal are required for use, they must be fastenedto a narrow slip of tin plate, one end of which is bent into the formof a hook, under which the plate of charcoal is pushed. 

In general, we use the charcoal support where we wish to reducemetallic oxides, to prevent oxidation, or to test the fusibility of asubstance. There is another point to which we would direct thestudent. Those metals which are volatile in the reduction flame, appear as oxides in the oxidation flame. These oxides make sublimatesupon the charcoal close in the vicinity of the substance, or where itrested, and by their peculiar color indicate pretty correctly thespecies of minerals experimented upon. 

(_b. _) _Platinum Supports. _--The metal platinum is infusible in theblowpipe flame, and is such a poor conductor of heat that a strip ofit may be held close to that portion of it which is red hot withoutthe least inconvenience to the fingers. It is necessary that thestudent should be cognizant of those substances which would not beappropriate to experiment upon if placed on platinum. Metals shouldnot be treated upon platinum apparatus, nor should the easilyreducible oxides, sulphides, nor chlorides, as these substances willcombine with the platinum, and thus render it unfit for further use inanalysis. 

(_c. _) _Platinum Wire. _--As the color of the flame cannot be welldiscerned when the substance is supported upon charcoal, inconsequence of the latter furnishing false colors, by its ownreflection, to the substances under examination, we use platinum wirefor that purpose, when we wish to examine those substances which giveindications by the peculiar color which they impart to fluxes. Thewire should be about as thick as No. 16 or 18 wire, or about 0. 4millimetre, and cut into pieces about from two and a half to threeinches in length. The end of each piece is crooked. In order thatthese pieces should remain clear of dirt, and ready for use, theyshould be kept in a glass of water. To use them, we dip the wettedhooked end into the powdered flux (borax or microcosmic salt) some ofwhich will adhere, when we fuse it in the flame of the blowpipe to abead. This bead hanging in the hook, must be clear and colorless. Should there not adhere a sufficient quantity of the flux in the firsttrial to form a bead sufficiently large, the hook must be dipped asecond time in the flux and again submitted to the blowpipe flame. Tofix the substance to be examined to the bead, it is necessary, whilethe latter is hot, to dip it in the powdered substance. If the hook iscold, we moisten the powder a little, and then dip the hook into it, and then expose it to the oxidation flame, by keeping it exposed to aregular blast until the substance and the flux are fused together, andno further alteration is produced by the flame. 

The platinum wire can be used except where reduction to the metallicstate is required. Every reduction and oxidation experiment, if theresults are to be known by the color of the fluxes, should be effectedupon platinum wire. At the termination of the experiment orinvestigation, if it be one, to, clean the wire, place it in water, which will dissolve the bead. 

(_d. _) _Platinum Foil. _--For the heating or fusing of a substance, whereby its reduction would be avoided, we use platinum foil as asupport. This foil should be of the thickness of good writing paper, and from two and a half to three inches long, by about half an inchbroad, and as even and smooth as possible. If it should become injuredby long use, cut the injured end off, and if it should prove too shortto be held with the fingers, a pair of forceps may be used to graspit, or it may be placed on a piece of charcoal. 

(_e. _) _Platinum Spoon. _--When we require to fuse substances with theacid sulphate of potash, or to oxidize them by detonation with nitrateof potash, whereby we wish to preserve the oxide produced, wegenerally use a little spoon of platinum, about from nine to fifteenmillimetres[1] in diameter, and shaped as represented in Fig. 7. Thehandle of this spoon is likewise of platinum, and should fit into apiece of cork, or be held with the forceps. 

 [1] The French millimetre is about the twenty-fifth part of an English inch. 

[Illustration: Fig. 7. ]

(_f. _) _Platinum Forceps or Tongs. _--We frequently are necessitated toexamine small splinters of metals or minerals directly in the blowpipeflame. These pieces of metallic substances are held with the forcepsor tongs represented as in Fig. 8, where _ac_ is formed of steel, and_aa_ are platinum bars inserted between the steel plates. At _bb_ areknobs which by pressure so separate the platinum bars _aa_, that anysmall substance can be inserted between them. 

[Illustration: Fig. 8. ]

(_g. _) _Iron Spoons. _--For a preliminary examination iron spoons aredesirable. They may be made of sheet iron, about one-third of an inchin diameter, and are very useful in many examinations where the use ofplatinum would not be desirable. 

(_h. _) _Glass Tubes. _--For the separation and recognition of volatilesubstances before the blowpipe flame, we use glass tubes. These shouldbe about one-eighth of an inch in diameter, and cut into pieces aboutfive or six inches in length. These tubes should have both ends open. 

Tubes are of great value in the examination of volatile substanceswhich require oxidizing or roasting, and heating with free access ofair. Also to ascertain whether a substance under examination willsublimate volatile matter of a certain appearance. Such substances areselenium, sulphur, arsenic, antimony, and tellurium. These substancescondense on a cool part of the tube, and they present characteristicappearances, or they may be recognized by their peculiar smell. Thesetubes must be made of the best kind of glass, white and difficult offusion, and entirely free from lead. The substance to be examined mustbe put in the tube near one end, and exposed to the flame of theblowpipe. The end containing the substance must be held lower than theother end, and must be moved a little over the spirit-lamp before adraught of air is produced through the tube. It is a good plan to havea number of these tubes on hand. After having used a tube we cut offthat end of it which contained the substance, with a file, and cleanit from the sublimate, either by heating it over the spirit-lamp, orwith a piece of paper wound around a wire. It sometimes happens thatthe substance falls out of the tube before it becomes sufficientlymelted to adhere to the glass. To obviate this, we bend the tube notfar from the end, at an obtuse angle, and place the substance in theangle, whereby the tube may be lowered as much as necessary. Fig. 9will give the student a comprehension of the processes described, andof the manner of bending the tubes. 

[Illustration: Fig. 9. ]

(_i. _) _Glass Tubes closed at one End. _--If we wish to expose volatilesubstances to heat, with the exclusion of air as much as possible, orto ascertain the contents of water, or other volatile fluids, or forthe purpose of heating substances which will decrepitate, we use glasstubes closed at one end. These tubes must be about one-eighth of aninch wide, and from two to three inches in length. They should be madeof white glass, difficult of fusion, and free from lead. They shouldbe closed at one end, as figured in the margin, Fig. 10. 

[Illustration: Fig. 10. ]

When a substance is to be examined for the purpose of ascertainingwhether it contains combustible matter, as sulphur or arsenic, andwhere we wish to avoid oxidation, we use these tubes without extendingthe closed end, in order that there may be as little air admitted aspossible, as is represented in tube B. But when a substance to beexamined is to be tested for water, or other incombustible volatilematters, we employ tubes with little bulbs blown at one end, such asrepresented at tube A. Here there is room for a circulation of air atthe bottom of the tube, by which the volatile matter rises moreeasily. In some cases, it is necessary to draw the closed end out to afine point, as in the tubes C and D. Either one or the other of thesetubes is employed, depending upon the nature of the substance used. The sublimates condense at the upper part of the tube _a_, and can bethere examined and recognized. These tubes, before being used, must bethoroughly dried and cleaned. In experimenting with them, they shouldnot be exposed at once to the hottest part of the flame, but should besubmitted to the heat gradually. If the substance is of such a naturethat it will sublime at a low heat, the tube should be held morehorizontal, while a higher heat is attained by bringing the tube to amore vertical position. 

VARIOUS APPARATUS NECESSARY. 

_Edulcorator or Washing Bottle. _--Take a glass bottle of the capacityof about twelve ounces, and close the mouth of it very tight with acork, through which a short glass tube is fitted airtight. Theexternal end of this tube is drawn out to a point, with a very fineorifice. The bottle should be filled about half full of water. Byblowing air into the bottle through the tube, and then turning itdownwards, the compressed air will expel a fine stream of waterthrough the fine orifice with considerable force. We use this washingbottle, Fig. 11, for the purpose of rinsing the small particles ofcoal from the reduced metals. 

[Illustration: Fig. 11. ]

_Agate Mortar and Pestle. _--This mortar is used for the purpose ofpulverizing hard substances, and for mixing fluxes. As this mortarwill not yield to abrasion, there is no danger of any foreign matterbecoming mixed with the substance pulverized in it. It should becleaned after use with pumice stone. Steel mortars are very useful forthe pulverization of hard bodies; but for all those substances whichrequire great care in their analysis, and which can be obtained invery minute quantity, the agate mortar alone should be used. 

A _hammer_ made of steel is necessary. This should have the edgesquare. 

A small _anvil_, polished on the surface, is also required. It isfrequently used to test the malleability of metals. 

A _knife_, for the purpose of ascertaining the hardness of minerals. 

The student should also be provided with several three-edged files, and likewise with some flat ones. 

A _microscope_, an instrument with two lenses, or with such acombination of lenses, that they may be used double or single, isfrequently necessary for the examination of blowpipe experiments, orthe reaction of the fluxes. Common lenses, howsoever cheap they maybe, are certainly not recommended. A microscope with achromatic lensescan now be purchased so cheap that there is no longer any necessity ofprocuring one with the common lens. Besides, there is no reliabilitywhatever to be placed in the revelations of the common lens; while onthe contrary, the deceptive appearances which minute objects assumebeneath such lenses are more injurious than otherwise. A small cheapset of magnifying glasses are all that is required for the purpose ofblowpipe analysis, Fig. 12. 

[Illustration: Fig. 12. ]

A small _magnet_ should be kept on hand, for the purpose of testingreduced metals. 

_Nippers_, for the purpose of breaking off pieces of minerals foranalysis, without injuring the entire piece, are indispensable, Fig13. 

[Illustration: Fig. 13. ]

A pair of _scissors_ is required to trim the wick of the and for thetrimming of the edge of platinum foil. 

A small _spatula_ should be kept for the purpose of mixing substanceswith fluxes. 

THE REAGENTS. 

Those substances which possess the property of acting upon othersubstances, in such a characteristic manner that they can berecognized, either by their color, or by their effervescence, or bythe peculiar precipitation produced, are termed _reagents_. Thephenomena thus produced is termed _reaction_. We use those reagents, or _tests_, for the purpose of ascertaining the presence or theabsence of certain substances, through the peculiar phenomena producedwhen brought in contact with them. 

The number of reagents employed in blowpipe analysis is not great, andtherefore we shall here give a brief description of their preparationand use. It is indispensably necessary that they should be chemicallypure, as every admixture of a foreign substance would only produce afalse result. Some of them have a strong affinity for water, or aredeliquescent, and consequently absorb it greedily from the air. Thesemust be kept in glass bottles, with glass stoppers, fitted air-tightby grinding. 

A. REAGENTS OF GENERAL USE. 

1. _Carbonate of Soda. _--(NaO, CO^{2}) Wash the bicarbonate of soda(NaO, 2CO^{2}) upon a filter, with cold water, until the filtrateceases to give, after neutralization with diluted nitric acid(NO^{5}), a precipitate with nitrate of baryta, (BaO, NO^{5}), ornitrate of silver, (AgO, NO^{5}). That left upon the filter we makered hot in a platinum, silver, or porcelain dish. One atom of carbonicacid is expelled, and the residue is carbonate of soda. 

A solution of soda must not be changed by the addition of sulphide ofammonium. And when neutralized with hydrochloric acid, and evaporatedto dryness, and again dissolved in water, there must be no residueleft. 

Carbonate of soda is an excellent agent in reduction, in consequenceof its easy fusibility, whereby it causes the close contact of theoxides with the charcoal support, so that the blowpipe flame can reachevery part of the substance under examination. 

For the decomposition and determination of insoluble substances, particularly the silicates, carbonate of soda is indispensable. Butfor the latter purpose, we use with advantage a mixture of ten partsof soda and thirteen parts of dry carbonate of potash, which mixturefuses more easily than the carbonate of soda alone. 

2. _Hydrate of Baryta_ (BaO, HO). --This salt is used sometimes for thedetection of alkalies in silicates. Mix one part of the substance withabout four parts of the hydrate of baryta, and expose it to theblowpipe flame. The hydrate of baryta combines with the silicic acid, and forms the super-basic silicate of baryta, while the oxides becomefree. The fused mass must be dissolved in hydrochloric acid, whichconverts the oxides into chlorides. Evaporate to dryness, and dissolvethe residue in water. The silicic acid remains insoluble. 

The hydrate of baryta is prepared by mixing six parts of finelypowdered heavy-spar (BaO, SO_{3}) with one part of charcoal and oneand a half parts of wheat flour, and exposing this mixture in aHessian crucible with a cover to a strong and continuous red heat. Thecooled chocolate-brown mass must be boiled with twenty parts of water, and, while boiling, there must be added the oxide of copper insufficient quantity, or until the liquid will not impart a black colorto a solution of acetate of lead (PbO, [=]A). The liquid must befiltered while hot, and as it cools the hydrate of baryta appears incrystals. These crystals must be washed with a little cold water, andthen heated at a low temperature in a porcelain dish until the crystalwater is expelled. The hydrate of baryta melts by a low red heatwithout losing its water of hydration. 

3. _Bisulphate of Potassa_ (KO, 2SO^{3}). --At a red heat the half ofthe sulphuric acid of this salt becomes free, and thus separates andexpels volatile substances, by which we can recognize lithium, boracicacid, nitric acid, fluoric acid, bromine, iodine, chlorine; or itdecomposes and reveals some other compounds, as, for instance, thesalts of the titanic, tantalic and tungstic acids. The bisulphate ofpotash is also used for the purpose of converting a substance intosulphate, or to free it at once from certain constituents. Thesesulphates are dissolved in water, by which we are enabled to effectthe separation of its various constituents. 

PREPARATION. --Two parts of coarsely powdered sulphate of potash areplaced in a porcelain crucible, and one part of pure sulphuric acid ispoured over it. Expose this to heat over the spirit-lamp, until thewhole becomes a clear liquid. The cooled mass must be of a pure whitecolor, and may be got out of the crucible by inverting it. It must bekept in a fine powder. 

4. _Oxalate of Potassa_ (KO, [=]O). --Dissolve bioxalate of potash inwater, and neutralize with carbonate of potash. Evaporate the solutionat a low heat to dryness, stirring constantly towards the close of theoperation. The dry residue is to be kept in the form of a powder. 

The oxalate of potash, at a low red heat, eliminates a considerablequantity of carbonic oxide, which, having a strong affinity foroxygen, with which it forms carbonic acid, it is therefore a powerfulagent of reduction. It is in many cases preferable to carbonate ofsoda. 

5. _Cyanide of Potassium_ (Cy, K). --In the dry method of analysis, this salt is one of the most efficient agents for the reduction ofmetallic oxides. It separates not only the metals from their oxygencompounds, but likewise from their sulphur compounds, while it isconverted through the action of the oxygen into carbonate of potash, or, in the latter case, combines with the sulphur and forms thesulphureted cyanide of potassium. This separation is facilitated byits easy fusibility. But in many cases it melts too freely, andtherefore it is better to mix it, for blowpipe analysis, with an equalquantity of soda. This mixture has great powers of reduction, and itis easily absorbed by the charcoal, while the globules of reducedmetal are visible in the greatest purity. 

PREPARATION. --Deprive the ferrocyanide of potassium (2KCy + FeCy) ofits water by heating it over the spirit-lamp in a porcelain dish. Mixeight parts of this anhydrous salt with three parts of dry carbonateof potash, and fuse the mixture by a low red heat in a Hessian, orstill better, in an iron crucible with a cover, until the mass flowsquiet and clear, and a sample taken up with an iron spatula appearsperfectly white. Pour the clear mass out into a china or porcelaindish or an iron plate, but with caution that the fine iron particleswhich have settled to the bottom, do not mix with it. The white fusedmass must be powdered, and kept from the air. The cyanide of potassiumthus prepared, contains some of the cyanate of potassa, but theadmixture does not deteriorate it for blowpipe use. It must beperfectly white, free from iron, charcoal, and sulphide of potassium. The solution of it in water must give a white precipitate with asolution of lead, and when neutralized with hydrochloric acid, andevaporated to dryness, it must not give an insoluble residue bydissolving it again in water. 

6. _Nitrate of Potassa, Saltpetre_ (KO, NO^{5}). --Saturate boilingwater with commercial saltpetre, filter while hot in a beaker glass, which is to be placed in cold water, and stir while the solution iscooling. The greater part of the saltpetre will crystallize in veryfine crystals. Place these crystals upon a filter, and wash them witha little cold water, until a solution of nitrate of silver ceases toexhibit any reaction upon the filtrate. These crystals must be driedand powdered. 

Saltpetre, when heated with substances easy of oxidation, yields itsoxygen quite readily, and is, therefore, a powerful means ofoxidation. In blowpipe analysis, we use it particularly to convertsulphides (as those of arsenic, antimony, &c. ) into oxides and acids. We furthermore use saltpetre for the purpose of producing a completeoxidation of small quantities of metallic oxides, which oxidize withdifficulty in the oxidation flame, so that the color of the bead, inits highest state of oxidation, shall be visible, as for instance, manganese dissolved in the microcosmic salt. 

7. _Biborate of soda, borax_--(NaO + 2BO^{3}). --Commercial borax isseldom pure enough for a reagent. A solution of borax must not give aprecipitate with carbonate of potassa; or, after the addition ofdilute nitric acid, it must remain clear upon the addition of nitrateof silver, or nitrate of baryta. Or a small piece of the dry salt, fused upon a platinum wire, must give a clear and uncolored glass, aswell in the oxidation flame as in the reduction flame. If these testsindicate a foreign admixture, the borax must be purified byre-crystallization. These crystals are washed upon a filter, dried, and heated, to expel the crystal water, or until the mass ceases toswell up, and it is reduced to powder. 

Boracic acid is incombustible, and has a strong affinity for oxideswhen fused with them; therefore, it not only directly combines withoxides, but it expels, by fusion, all other volatile acids from theirsalts. Furthermore, boracic acid promotes the oxidation of metals andsulphur, and induces haloid compounds, in the oxidation flame, tocombine with the rising oxides. Borates thus made, melt generally bythemselves; but admixed with borate of soda, they fuse much morereadily, give a clear bead. Borax acts either as a flux, or throughthe formation of double salts. 

In borax, we have the action of free boracic acid, as well as borateof soda, and for that reason it is an excellent reagent for blowpipeanalysis. 

All experiments in which borax is employed should be effected uponplatinum wire. The hook of the wire should be heated red hot, and thendipped into the powdered borax. This should be exposed to theoxidation flame, when it will be fused to a bead, which adheres to thehook. This should be then dipped into the powdered substance, whichwill adhere to it if it is hot; but if the bead is cool, it must bepreviously moistened. Expose this bead to the oxidation flame until itceases to change, then allow it to cool, when it should be exposed tothe reduction flame. Look for the following in the oxidation flame:

 (1. ) Whether the heated substance is fused to a clear bead or not, and whether the bead remains transparent after cooling. The beads of some substances, for instance those of the alkaline earths, are clear while hot; but upon cooling, are milk-white and enamelled. Some substances give a clear bead when heated and when cold, but appear enamelled when heated intermittingly or with a flame which changes often from oxidation to reduction, or with an unsteady flame produced by too strong a blast. The reason is an incomplete fusion, while from the basic borate compound a part of the base is separated. As the boracic acid is capable of dissolving more in the heat, a bead will be clear while hot, enamelled when cold, as a part in the latter instance will become separated. 

 (2. ) Whether the substance dissolves easily or not, and whether it intumesces from arising gases. 

 (3. ) Whether the bead, when exposed to the oxidation flame, exhibits any color, and whether the color remains after the bead shall have cooled, or whether the color fades. 

 (4. ) Whether the bead exhibits any other reaction in the reduction flame. 

The bead should not be overcharged with the substance underexamination, or it will become colored so deeply as not to present anytransparency, or the color light enough to discern its hue. 

8. _Microcosmic Salt--Phosphate of Soda and Ammonia_--(NaO, NH^{4}O +PO^{5}). --Dissolve six parts of phosphate of soda (2NaO, HO, PO^{5}), and one part of pure chloride of Ammonium (NH^{4}Cl. ), in two parts ofboiling water, and allow it to cool. The greatest part of the formeddouble salt crystallizes, while the mother-liquid contains chloride ofsodium, and some of the double salt. The crystals must be dissolved inas little boiling water as possible, and re-crystallized. Thesecrystals must be dried and powdered. 

When this double salt is heated, the water and the ammonia escape, while the incombustible residue has a composition similar to borax, viz. , a free acid and an easily fusible salt. The effect of it is, therefore, similar to the borax. The free phosphoric acid expels, likewise, most other acids from their combinations, and combines withmetallic oxides. 

For supports, the platinum wire may be used, but the hook must besmaller than when borax is used, or the bead will not adhere. As forall the other experiments with this salt, the microscosmic salt isused the same as borax. 

9. _Nitrate of Cobalt. _--(CoO, NO^{5}). --This salt can be prepared bydissolving pure oxide of cobalt in diluted nitric acid, andevaporating to dryness with a low heat. The dry residue should bedissolved in ten parts of water, and filtered. The filtrate is nowready for use, and should be kept in a bottle with a glass stopper. Ifthe pure oxide of cobalt cannot be procured, then it may be preparedby mixing two parts of finely powdered _glance of cobalt_ with fourparts of saltpetre, and one part of dry carbonate of potassa with onepart of water free from carbonate of soda. This mixture should beadded in successive portions into a red-hot Hessian crucible, and theheat continued until the mass is fused, or at least greatly diminishedin volume. The cooled mass must be triturated with hot water, and thenheated with hydrochloric acid until it is dissolved and forms a darkgreen solution, which generally presents a gelatinous appearance, occasioned by separated silica. The solution is to be evaporated todryness, the dry residue moistened with hydrochloric acid, boiled withwater, filtered and neutralized while hot with carbonate of ammonia, until it ceases to give an acid reaction with test-paper. This mustnow be filtered again, and carbonate of potassa added to the filtrateas long as a precipitate is produced. This precipitate is brought upona filter and washed thoroughly, and then dissolved in diluted nitricacid. This is evaporated to dryness, and one part of it is dissolvedin ten parts of water for use. 

The oxide of cobalt combines, with strong heat in the oxidation flame, with various earths and infusible metallic oxides, and thus producespeculiarly colored compounds, and is therefore used for theirdetection; (alumina, magnesia, oxide of zinc, oxide of tin, etc. ) Someof the powdered substance is heated upon charcoal in the flame ofoxidation, and moistened with a drop of the solution of the nitrate ofcobalt, when the oxidation flame is thrown upon it. Alumina gives apure blue color, the oxide of zinc a bright green, magnesia a lightred, and the oxide of tin a bluish-green color; but the latter is onlydistinctly visible after cooling. 

The dropping bottle, is the most useful apparatus for the purpose ofgetting small quantities of fluid. It is composed of a glass tube, drawn out to a point, with a small orifice. This tube passes throughthe cork of the bottle. By pressing in the cork into the neck of thebottle, the air within will be compressed, and the liquid will rise inthe tube. If now we draw the cork out, with the tube filled with thefluid, and pressing the finger upon the upper orifice, the fluid canbe forced out in the smallest quantity, even to a fraction of a drop. 

10. _Tin. _--This metal is used in the form of foil, cut into stripsabout half an inch wide. Tin is very susceptible of oxidation, andtherefore deprives oxidized substances of their oxygen very quickly, when heated in contact with them. It is employed in blowpipe analysis, for the purpose of producing in glass beads a lower degree ofoxidation, particularly if the substance under examination containsonly a small portion of such oxide. These oxides give a characteristiccolor to the bead, and thus are detected. The bead is heated uponcharcoal in the reduction flame, with a small portion of the tin, whereby some of the tin is melted and mixes with the bead. The beadshould be reduced quickly in the reduction flame, for by continuingthe blast too great a while, the oxide of tin separates the otheroxides in the reduced or metallic state, while we only require thatthey shall only be converted into a sub-oxide, in order that itspeculiar color may be recognized in the bead. The addition of too muchtin causes the bead to present an unclean appearance, and preventsthe required reaction. 

11. _Silica_ (SiO^{3}). --This acid does not even expel carbonic acidin the wet way, but in a glowing heat it expels the strongest volatileacids. In blowpipe analysis, we use it fused with carbonate of soda toa bead, as a test for sulphuric acid, and in some cases for phosphoricacid. Also with carbonate of soda and borax, for the purpose ofseparating tin from copper. 

Finely powdered quartz will answer these purposes. If it cannot beprocured, take well washed white sand and mix it with two parts ofcarbonate of soda and two parts of carbonate of potassa. Melt thematerials together, pound up the cooled mass, dissolve in hot water, filter, add to the filtrate hydrochloric acid, and evaporate todryness. Moisten the dry residue with hydrochloric acid, and boil inwater. The silica remains insoluble. It should be washed well, dried, and heated, and then reduced to powder. 

12. TEST-PAPERS. --(_a. _) _Blue, Litmus Paper. _--Dissolve one part oflitmus in six or eight parts of water, and filter. Divide the filtrateinto two parts. In one of the parts neutralize the free alkali bystirring it with a glass rod dipped in diluted sulphuric acid, untilthe fluid appears slightly red. Then mix the two parts together, anddraw slips of unsized paper, free from alkali, such as fine filteringpaper. Hang these strips on a line to dry, in the shade and free fromfloating dust. If the litmus solution is too light, it will not givesufficient characteristic indications, and if too dark it is notsensitive enough. The blue color of the paper should be changed tored, when brought in contact with a solution containing the minutesttrace of free acid; but it should be recollected that the neutralsalts of the heavy metals produce the same change. 

(_b. _) _Red Litmus Paper. _--The preparation of the red litmus paper issimilar to the above, the acid being added until a red color isobtained. Reddened litmus paper is a very sensitive reagent for freealkalies, the carbonates of the alkalies, alkaline earths, sulphidesof the alkalies and of the alkaline earths, and alkaline salts withweak acids, such as boracic acid. These substances restore theoriginal blue color of the litmus. 

(_c. _) _Logwood Paper. _--Take bruised logwood, boil it in water, filter, and proceed as above. Logwood paper is a very delicate testfor free alkalies, which impart a violet tint to it. It is sometimesused to detect hydrofluoric acid, which changes its color to yellow. 

All the test-papers are to be cut into narrow strips, and preserved inclosely stopped vials. The especial employment of the test-papers weshall allude to in another place. 

B. ESPECIAL REAGENTS. 

13. _Fused Boracic Acid_ (BO^{3}). --The commercial article issufficiently pure for blowpipe analysis. It is employed in some casesto detect phosphoric acid, and also minute traces of copper in leadcompounds. 

14. _Fluorspar_ (CaFl^{2}). --This substance should be pounded fine andstrongly heated. Fluorspar is often mixed with boracic acid, whichrenders it unfit for analytical purposes. Such an admixture can bedetected if it be mixed with bisulphate of potassa, and exposed uponplatinum wire to the interior or blue flame. It is soon fused, theboracic acid is reduced and evaporated, and by passing through theexternal flame it is reoxidized, and colors the flame green. We usefluorspar mixed with bisulphate of potassa as a test for lithia andboracic acid in complicated compounds. 

15. _Oxalate of Nickel_ (NiO, [=]O). --It is prepared by dissolving thepure oxide of nickel in diluted hydrochloric acid. Evaporate todryness, dissolve in water, and precipitate with oxalate of ammonia. The precipitate must be washed with caution upon a filter, and thendried. It is employed in blowpipe analysis to detect salts of potassain the presence of sodium and lithium. 

16. _Oxide of Copper_ (CuO). --Pure metallic copper is dissolved innitric acid. The solution is evaporated in a porcelain dish todryness, and gradually heated over a spirit-lamp, until the blue colorof the salt has disappeared and the mass presents a uniform blackcolor. The oxide of copper so prepared must be powdered, and preservedin a vial. It serves to detect, in complicated compounds, minutetraces of chlorine. 

17. _Antimoniate of Potassa_ (KO, SbO^{6}). --Mix four parts of thebruised metal of antimony, with nine parts of saltpetre. Throw thismixture, in small portions, into a red-hot Hessian crucible, and keepit at a glowing heat for awhile after all the mixture is added. Boilthe cooled mass with water, and dry the residue. Take two parts ofthis, and mix it with one part of dry carbonate of potassa, and exposethis to a red heat for about half an hour. Then wash the mass in coldwater, and boil the residue in water; filter, evaporate the filtrateto dryness, and then, with a strong heat, render it free of water. Powder it while it is warm, and preserve it in closed vials. It isused for the detection of small quantities of charcoal in compoundsubstances, as it shares its oxygen with the carbonaceous matter, theantimony becomes separated, and carbonate of potassa is produced, which restores red litmus paper to blue, and effervesces with acids. 

18. _Silver Foil. _--A small piece of silver foil is used for thepurpose of detecting sulphur and the sulphides of the metals, whichimpart a dark stain to it. If no silver foil is at hand, strips offiltering paper, impregnated with acetate of lead, will answer in manycases. 

19. _Nitroprusside of Sodium_ (Fe^{2}Cy^{5}, NO^{5}, 2Na). --This is avery delicate test for sulphur, and was discovered by Dr. Playfair. This test has lately been examined with considerable ability by Prof. J. W. Bailey, of West Point. If any sulphate or sulphide is heated bythe blowpipe upon charcoal with the carbonate of soda, and the fusedmass is placed on a watch-glass, with a little water, and a smallpiece of the nitroprusside of sodium is added, there will be produceda splendid purple color. This color, or reaction, will be producedfrom any substance containing sulphur, such as the parings of thenails, hair, albumen, etc. In regard to these latter substances, thecarbonate of soda should be mixed with a little starch, which willprevent the loss of any of the sulphur by oxidation. Coil a piece ofhair around a platinum wire, moisten it, and dip it into a mixture ofcarbonate of soda, to which a little starch has been added, and thenheat it with the blowpipe, when the fused mass will give with thenitroprusside of sodium the characteristic purple reaction, indicativeof the presence of sulphur. With the proper delicacy of manipulation, a piece of hair, half an inch in length, will give distinctindications of sulphur. 

_Preparation. _--The nitroprussides of sodium and potassium (for eithersalt will give the above reactions), are prepared as follows: One atom(422 grains) of pulverized ferrocyanide of potassium is mixed withfive atoms of commercial nitric acid, diluted with an equal quantityof water. One-fifth of this quantity (one atom) of the acid issufficient to transfer the ferrocyanide into nitroprusside; but theuse of a larger quantity is found to give the best results. The acidis poured all at once upon the ferrocyanide, the cold produced by themixing being sufficient to moderate the action. The mixture firstassumes a milky appearance, but after a little while, the saltdissolves, forming a coffee-colored solution, and gases are disengagedin abundance. When the salt is completely dissolved, the solution isfound to contain ferrocyanide (red prussiate) of potassium, mixed withnitroprusside and nitrate of the same base. It is then immediatelydecanted into a large flask, and heated over the water-bath. Itcontinues to evolve gas, and after awhile, no longer yields a darkblue precipitate with ferrous salts, but a dark green or slate-coloredprecipitate. It is then removed from the fire, and left tocrystallize, whereupon it yields a large quantity of crystals ofnitre, and more or less oxamide. The strongly-colored mother liquid isthen neutralized with carbonate of potash or soda, according to thesalt to be prepared, and the solution is boiled, whereupon itgenerally deposits a green or brown precipitate, which must beseparated by filtration. The liquid then contains nothing butnitroprusside and nitrate of potash or soda. The nitrates being theleast soluble, are first crystallized, and the remaining liquid, onfarther evaporation, yields crystals of the nitroprusside. The sodiumsalt crystallizes most easily. --(PLAYFAIR. )

As some substances, particularly in complicated compounds, are notdetected with sufficient nicety in the dry way of analysis, it willoften be necessary to resort to the wet way. It is therefore necessaryto have prepared the reagents required for such testing, as everyperson, before he can become an expert blowpipe analyst, must beacquainted with the characteristic tests as applied in the wet way. 

 * * * * *

Part II. 

INITIATORY ANALYSIS. 

Qualitative analysis refers to those examinations which relate simplyto the presence or the absence of certain substances, irrespective oftheir quantities. But before we take cognizance of specialexaminations, it would facilitate the progress of the student to passthrough a course of Initiatory Exercises. These at once lead into thespecial analysis of all those substances susceptible of examination bythe blowpipe. The Initiatory Analysis is best studied by adopting thefollowing arrangement:

1. EXAMINATIONS WITH THE GLASS BULB. 

The glass of which the bulb is made should be entirely free from lead, otherwise fictitious results will ensue. If the bulb be of flintglass, then by heating it, there is a slightly iridescent film causedupon the surface of the glass, which may easily be mistaken forarsenic. Besides, this kind of glass is easily fusible in theoxidating flame of the blowpipe, while, in the reducing flame, itsready decomposition would preclude its use entirely. The tube shouldbe composed of the potash or hard Bohemian glass, should be perfectlywhite, and very thin, or the heat will crack it. 

The tube should be perfectly clean, which can be easily attained bywrapping a clean cotton rag around a small stick, and inserting it inthe tube. Before using the tube, see also that it is perfectly dry. 

The quantity of the substance put into the tube for examination shouldbe small. From one to three grains is quite sufficient, as a generalrule, but circumstances vary the quantity. The sides of the tubeshould not catch any of the substance as it is being placed at thebottom of the tube, or into the bulb. If any of the powder, however, should adhere, it should be pushed down with a roll of clean paper, orthe clean cotton rag referred to above. 

In submitting the tube to the flame, it should be heated at first verygently, the heat being increased until the glass begins to soften, when the observations of what is ensuing within it may be made. 

If the substance be of an organic nature, a peculiar empyreumatic odorwill be given off. If the substance chars, then it may be inferredthat it is of an organic nature. The matters which are given off andcause the empyreumatic odor, are a peculiar oil, ammonia, carbonicacid, acetic acid, water, cyanogen, and frequently other compounds. Ifa piece of paper is heated in the bulb, a dark colored oil condensesupon the sides of the tube, which has a strong empyreumatic odor. Apiece of litmus paper indicates that this oil is acid, as it isquickly changed to red by contact with it. A black residue is now leftin the tube, and upon examination we will find that it is charcoal. If, instead of the paper, a piece of animal substance is placed inthe bulb, the reddened litmus paper will be converted into itsoriginal blue color, while charcoal will be left at the bottom of thetube. 

A changing of the substance, however, to a dark color, should not beaccepted as an invariable indication of charcoal, as some inorganicbodies thus change color, but the dark substance will not be likely tobe mistaken for charcoal. By igniting the suspected substance withnitrate of potassa, it can quickly be ascertained whether it isorganic or not, for if the latter, the vivid deflagration willindicate it. 

If the substance contains water, it will condense upon the coldportion of the tube, and may be there examined as to whether it isacid or alkaline. If the former, the matter under examination is, perhaps, vegetable; if the latter, it is of an animal nature. Thewater may be that fluid absorbed, or it may form a portion of itsconstitution, If the substance contain _sulphur_, the sublimate upon the cold partof the tube may be recognized by its characteristic appearance, especially if the substance should be a sulphide of tin, copper, antimony, or iron. The hyposulphites, and several other sulphides, also give off sulphur when heated. The volatile metals, mercury andarsenic, will, however, sublime without undergoing decomposition. Asthe sulphide of arsenic may be mistaken, from its color andappearance, for sulphur, it must be examined especially for thepurpose of determining that point. 

_Selenium_ will likewise sublime by heat as does sulphur. This is thecase if selenides are present. Selenium gives off the smell of decayedhorse-radish. 

When the persalts are heated they are reduced to protosalts, with theelimination of a part of their acid. This will be indicated by theblue litmus paper. 

If some of the neutral salts containing a volatile acid be present, they will become decomposed. For instance, the red nitrous acid waterof the nitrates will indicate the decomposition of the salt, especially if it be the nitrate of a metallic oxide. 

If there is an odor of sulphur, then it is quite probable, if no freesulphur be present, that a hyposulphite is decomposed. 

If an oxalate be present, it is decomposed with the evolution ofcarbonic oxide, which may be inflamed at the mouth of the tube; butthere are oxalates that give off carbonic acid gas, which, of course, will not burn. A cyanide will become decomposed and eliminate nitrogengas, while the residue is charred. Some cyanides are, however, notthus decomposed, as the dry cyanides of the earths and alkalies. 

There are several oxides of metals which will sublime, and may be thusexamined in the tube. _Arsenious acid_ sublimes with great ease inminute octohedral crystals. The oxides of tellurium and antimony willsublime, the latter in minute glittering needles. 

There are several metals which will sublime, and may be examined inthe cold portion of the tube. _Mercury_ condenses upon the tube inminute globules. These often do not present the metallic appearanceuntil they are disturbed with a glass rod, when they attract eachother, and adhere as small globules. Place in the tube about a grainof red precipitate of the drug stores and apply heat, when the oxidewill become decomposed, its oxygen will escape while the vaporizedmercury will condense upon the cold portion of the tube, and may therebe examined with a magnifying glass. 

_Arsenic_, when vaporized, may be known by its peculiar alliaceousodor. Arsenic is vaporized from its metallic state, and likewise fromits alloys. Several compounds which contain arsenic will also sublime, such as the arsenical cobalt. Place in the bulb a small piece ofarsenical cobalt or "fly-stone, " and apply heat. The sulphide ofarsenic will first rise, but soon the arsenic will adhere to the sidesof the tube. 

The metals tellurium and cadmium are susceptible of solution, but theheat required is a high one. This is best done upon charcoal. 

The _perchloride of mercury_ sublimes undecomposed in the bulb, previously undergoing fusion. 

The _protochloride of mercury_ likewise sublimes, but it does notundergo fusion first, as is the case with the corrosive sublimate. 

The _ammoniacal salts_ all are susceptible of sublimation, which theydo without leaving a residue. There are, however, several whichcontain fixed acids, which latter are left in the bulb. This isparticularly the case with the phosphates and borates. A piece of redlitmus paper will readily detect the escaping ammonia, while its odorwill indicate its presence with great certainty. The halogen compoundsof mercury, we should have mentioned, also sublime, the red iodidegiving a yellow sublimate. 

The bulb is also a convenient little instrument for the purpose ofheating those substances which phosphoresce, and likewise those saltsthat decrepitate. 

Should the above reactions not be readily discerned, it should not beconsidered as an indication that the substances are not present, forthey are frequently expelled in such combinations that the abovereactions will not take place. This is often the case with sulphur, selenium, arsenic, and tellurium. It frequently happens, likewise, that these substances are in such combinations that heat alone willnot sublime them; or else two or more of them may arise together, andthus complicate the sublimate, so that the eye cannot readily detecteither substance. Sometimes sulphur and arsenic will coat the tubewith a metal-like appearance, which is deceptive. This coatingpresents a metallic lustre at its lower portion, but changing, as itprogresses upward, to a dark brown, light brown, orange or yellow;this sublimate being due to combinations of arsenic and sulphur, whichcompounds are volatilized at a lower temperature than metallicarsenic. 

If certain reagents are mixed with many substances, changes areeffected which would not ensue with heat alone. _Formiate of soda_possesses the property of readily reducing metallic oxides. When thissalt is heated, it gives off a quantity of carbonic oxide gas. Thisgas, when in the presence of a metallic oxide, easily reduces themetal, by withdrawing its oxygen from it, and being changed intocarbonic oxide. If a little fly-stone is mixed with some formiate ofsoda, and heated in the bulb, the arsenic is reduced, volatilized, andcondenses in the cool portion of the tube. By this method, thesmallest portion of a grain of the arsenical compound may be thusexamined with the greatest readiness. If the residue is now washed, bywhich the soda is got rid of, the metallic arsenic may be obtained insmall spangles. If the compound examined be the sulphide of antimony, the one-thousandth part can be readily detected, and hence this methodis admirably adapted to the examination of medicinal antimonialcompounds. The arsenites of silver and copper are reduced by theformiate of soda to their metals, mixed with metallic arsenic. Themercurial salts are all reduced with the metal plainly visible as abright silvery ring on the cool portion of the tube. The chloride andnitrate of silver are completely reduced, and may be obtained afterworking out the soda, as bright metallic spangles. The salts ofantimony and zinc are thus reduced; also the sulphate of cadmium. Thesublimate of the latter, although in appearance not unlike that ofarsenic, can easily be distinguished by its brighter color. It is, infact, the rich yellow of this sublimate which has led artists to adoptit as one of their most valued pigments. 

2. EXAMINATIONS IN THE OPEN TUBE. 

The substance to be operated upon should be placed in the tube, abouthalf an inch from the end, and the flame applied at first verycautiously, increasing gradually to the required temperature. Thetube, in all these _roasting_ operations, as they are termed, shouldbe held in an inclined position. The nearer perpendicular the tube isheld, the stronger is the draught of air that passes through it. Ifbut little heat is required in the open tube operation, thespirit-lamp is the best method of applying the heat. But if a greatertemperature is required, then recourse must be had to the blowpipe. Upon the angle of inclination of the tube depends the amount of airthat passes through it, and therefore, the rapidity of the draughtmay be easily regulated at the will of the operator. The inclinationof the tube may, as a general rule, be about the angle represented inFig. 14. 

[Illustration Fig. 14. ]

The length of the tube must be about six inches, so that the portionupon which the substance rested in a previous examination may be cutoff. The portion of the tube left will answer for several similaroperations. 

When the substance is under examination, we should devote ourattention to the nature of the sublimates, and to that of the _odors_of the gases. If sulphur be in the substance experimented upon, thecharacteristic odor of sulphurous acid gas will readily indicate thesulphur. If metallic sulphides, for instance, are experimented upon, the sulphurous acid gas eliminated will readily reveal their presence. As it is a property of this gas to bleach, a piece of Brazil-wood testpaper should be held in the mouth of the tube, when its loss of colorwill indicate the presence of the sulphurous acid. It often happens, too, that a slight deposition of sulphur will be observed upon thecool portion of the tube. This is particularly the case with thosesulphides, which yield sublimates of sulphur when heated in the bulb. 

_Selenium_ undergoes but slight oxidation, but it becomes readilyvolatilized, and may be observed on the cool portion of the tube. Atthe same time the nose, if applied close to the end of the tube, willdetect the characteristic odor of rotten horse-radish. Arsenic alsogives its peculiar alliaceous odor, which is so characteristic that itcan be easily detected. A few of the arsenides produce this odor. The_sublimates_ should be carefully observed, as they indicate often withgreat certainty the presence of certain substances; for instance, thatof arsenic. The sublimate, in this case, presents itself as thearsenious acid, or the metallic arsenic itself. If it be the former, it may be discerned by aid of the magnifying glass as beautifulglittering octohedral crystals. If the latter, the metallic lustrewill reveal it. 

But it will be observed that while some of the arsenides are sublimedat a comparatively low temperature, others require a very high one. 

_Antimony_ gives a white sublimate when its salts are roasted, as thesulphide, or the antimonides themselves, or the oxide of this metal. This white sublimate is not antimonious acid, but there is mixed withit the oxide of antimony with which the acid is sublimed. As is thecase with arsenious acid, the antimonious acid may, by dexterousheating, be driven from one portion of the tube to another. 

_Tellurium_, or its acid and oxide, may be got as a sublimate in thetube. The tellurious acid, unlike the arsenious and antimonious acids, cannot be driven from one portion of the tube to another, but, on thecontrary, it fuses into small clear globules, visible to the naked eyesometimes, but quite so with the aid of the magnifying glass. 

_Lead_, or its chloride, sublimes like tellurium, and, like thatsubstance, fuses into globules or drops. 

_Bismuth_, or its sulphide, sublimes into an orange or brownishglobules, when it is melted, as directed above, for tellurium. Thecolor of the bismuth and lead oxides are somewhat similar, althoughthat of the latter is paler. 

If any mineral containing _fluorine_, is fused, first with themicrocosmic salt bead, then put into the tube, and the flame of theblowpipe be directed _into_ the tube upon the bead, hydrofluoric acidis disengaged and attacks the inside of the tube. The fluoride ofcalcium, or fluorspar, may be used for this experiment. 

During the roasting, a brisk current of air should be allowed to passthrough the tube, whereby unoxidized matter may be prevented fromvolatilization, and the clogging up of the substance under examinationbe prevented. 

3. EXAMINATIONS UPON CHARCOAL. 

In making examinations upon charcoal, it is quite necessary that thestudent should make himself familiar with the different andcharacteristic appearances of the deposits upon the charcoal. In thiscase I have found the advice given by Dr. Sherer to be the best; thatis, to begin with the examination of the pure materials first, untilthe eye becomes familiarized with the appearances of theirincrustations upon charcoal. 

The greater part of the metals fuse when submitted to the heat of theblowpipe, and if exposed to the outer flame, they oxidize. Thesemetals, termed the noble metals, do not oxidize, but they fuse. Themetals platinum, iridium, rhodium, osmium and palladium do not fuse. The metal osmium, if exposed to the flame of oxidation, fuses and isfinally dissipated as osmic acid. In the latter flame, the salts ofthe noble metals are reduced to the metallic state, and the charcoalis covered with the bright metal. 

We shall give a brief description of the appearance of the principalelementary bodies upon being fused with charcoal. This plan is thatdeemed the most conducive to the progress of the student, byBerzelius, Plattner, and Sherer. Experience has taught us that thismethod is the most efficient that could have been devised as aninitiatory exercise for the student, ere he commences a more conciseand methodical method of analysis. In these reactions upon charcoal, we shall follow nearly the language of Plattner and Sherer. 

SELENIUM is not difficult of fusion, and gives off brown fumes ineither the oxidation or reduction flame. The deposit upon the charcoalis of a steel-grey color, with a slightly metallic lustre. The deposithowever that fuses outside of this steel-grey one is of a dull violetcolor, shading off to a light brown. Under the flame of oxidation thisdeposit is easily driven from one portion of the charcoal to another, while the application of the reducing flame volatilizes it with theevolution of a beautiful blue light. The characteristic odor ofdecayed horse-radish distinguishes the volatilization of this metal. 

TELLURIUM. --This metal fuses with the greatest readiness, and isreduced to vapor under both flames with fumes, and coats the charcoalwith a deposit of tellurous acid. This deposit is white near thecentre, and is of a dark yellow near the edges. It may be driven fromplace to place by the flame of oxidation, while that of reductionvolatilizes it with a green flame. If there be a mixture of seleniumpresent, then the color of the flame is bluish-green. 

ARSENIC. --This metal is volatilized without fusing, and covers thecharcoal both in the oxidizing and reducing flames with a deposit ofarsenious acid. This coating is white in the centre, and grey towardsthe edges, and is found some distance from the assay. By the mostgentle application of the flame, it is immediately volatilized, and iftouched for a moment with the reducing flame, it disappears, tingingthe flame pale blue. During volatilization a strong garlic odor isdistinctly perceptible, very characteristic of arsenic, and by whichits presence in any compound may be immediately recognized. 

ANTIMONY. --This metal fuses readily, and coats the charcoal under bothflames with antimonious acid. This incrustation is of a white colorwhere thick, but of a bluish tint where it is thin, and is foundnearer to the assay than that of arsenic. When greatly heated by theflame of oxidation, it is driven from place to place without coloringthe flame, but when volatilized by the flame of reduction, it tingesthe flame blue. As antimonious acid is not so volatile as arseniousacid, they may thus be easily distinguished from one another. 

When metallic antimony is fused upon charcoal, and the metallic beadraised to a red heat, if the blast be suspended, the fluid beadremains for some time at this temperature, giving off opaque whitefumes, which are at first deposited on the surrounding charcoal, andthen upon the bead itself, covering it with white, pearly crystals. The phenomenon is dependent upon the fact, that the heated button ofantimony, in absorbing oxygen from the air, developes sufficient heatto maintain the metal in a fluid state, until it becomes entirelycovered with crystals of antimonious acid so formed. 

BISMUTH. --This metal fuses with ease, and under both flames covers thecharcoal with a coating of oxide, which, while hot, is of anorange-yellow color, and after cooling, of a lemon-yellow color, passing, at the edges, into a bluish white. This white coatingconsists of the carbonate of bismuth. The sublimate from bismuth isformed at a less distance from the assay than is the case withantimony. It may be driven from place to place by the application ofeither flame; but in so doing, the oxide is first reduced by theheated charcoal, and the metallic bismuth so formed is volatilized andreoxidized. The flame is uncolored. 

LEAD. --This metal readily fuses under either flame, and incrusts thecharcoal with oxide at about the same distance from the assay as isthe case with bismuth. The oxide is, while hot, of a dark lemon-yellowcolor, but upon cooling, becomes of a sulphur yellow. The carbonatewhich is formed upon the charcoal, beyond the oxide, is of abluish-white color. If the yellow incrustation of the oxide be heatedwith the flame of oxidation, it disappears, undergoing changes similarto those of bismuth above mentioned. Under the flame of reduction, it, however, disappears, tinging the flame blue. 

CADMIUM. --This metal fuses with ease, and, in the flame of oxidation, takes fire, and burns with a deep yellow color, giving off brownfumes, which coat the charcoal, to within a small distance of theassay, with oxide of cadmium. This coating exhibits its characteristicreddish-brown color most clearly when cold. Where the coating is verythin, it passes to an orange color. As oxide of cadmium is easilyreduced, and the metal very volatile, the coating of oxide may bedriven from place to place by the application of either flame, toneither of which does it impart any color. Around the deposit ofoxide, the charcoal has occasionally a variegated tarnish. 

ZINC. --This metal fuses with ease, and takes fire in the flame ofoxidation, burning with a brilliant greenish-white light, and formingthick white fumes of oxide of zinc, which coat the charcoal round theassay. This coating is yellow while hot, but when perfectly cooled, becomes white. If heated with the flame of oxidation, it shinesbrilliantly, but is not volatilized, since the heated charcoal is, under these circumstances, insufficient to effect its reduction. Evenunder the reducing flame, it disappears very slowly. 

TIN. --This metal fuses readily, and, in the flame of oxidation, becomes covered with oxide, which, by a strong blast, may be easilyblown off. In the reducing flame, the fused metal assumes a whitesurface, and the charcoal becomes covered with oxide. This oxide is ofa pale yellow color while hot, and is quite brilliant when the flameof oxidation is directed upon it. After cooling, it becomes white. Itis found immediately around the assay, and cannot be volatilized bythe application of either flame. 

MOLYBDENUM. --This metal, in powder, is infusible before the blowpipe. If heated in the outer flame, it becomes gradually oxidized, andincrusts the charcoal, at a small distance from the assay, withmolybdic acid, which, near the assay, forms transparent crystallinescales, and is elsewhere deposited as a fine powder. The incrustation, while hot, is of a yellow color, but becomes white after cooling. Itmay be volatilized by heating with either flame, and leaves thesurface of the charcoal, when perfectly cooled, of a dark-red coppercolor, with a metallic lustre, due to the oxide of molybdenum, whichhas been formed by the reducing action of the charcoal upon themolybdic acid. In the reducing flame, metallic molybdenum remainsunchanged. 

SILVER. --This metal, when fused alone, and kept in this state for sometime, under a strong oxidizing flame, covers the charcoal with a thinfilm of dark reddish-brown oxide. If the silver be alloyed with lead, a yellow incrustation of the oxide of that metal is first formed, andafterwards, as the silver becomes more pure, a dark red deposit isformed on the charcoal beyond. If the silver contains a small quantityof antimony, a white incrustation of antimonious acid is formed, whichbecomes red on the surface if the blast be continued. And if lead andantimony are both present in the silver, after the greater part ofthese metals have been volatilized, a beautiful crimson incrustationis produced upon the charcoal. This result is sometimes obtained infusing rich silver ores on charcoal. 

SULPHIDES, CHLORIDES, IODIDES, AND BROMIDES. 

In blowpipe experiments, it rarely occurs that we have to deal withpure metals, which, if not absolutely non-volatile, are recognized bythe incrustation they form upon charcoal. Some compound substances, when heated upon charcoal, form white incrustations, resembling thatformed by antimony, and which, when heated, may, in like manner, bedriven from place to place. Among these are certain sulphides, assulphide of potassium, and sulphide of sodium, which are formed by theaction of the reducing flame upon the sulphates of potassa and soda, and are, when volatilized, reconverted into those sulphates, and assuch deposited on the charcoal. No incrustation is, however, formed, until the whole of the alkaline sulphate has been absorbed into thecharcoal, and has parted with its oxygen. As sulphide of potassium ismore volatile than sulphide of sodium, an incrustation is formed fromthe former sooner than from the latter of these salts, and isconsiderably thicker in the former case. If the potash incrustation betouched with the reducing flame, it disappears with a violet-coloredflame; and if a soda incrustation be treated in like manner, anorange-yellow flame is produced. 

Sulphide of lithium, formed by heating the sulphate in the reducingflame, is volatilized in similar manner by a strong blast, althoughless readily than the sulphide of sodium. It affords a greyish whitefilm, which disappears with a crimson flame when submitted to thereducing flame. 

Besides the above, the sulphides of bismuth and lead give, when heatedin either flame, two different incrustations, of which the morevolatile is of a white color, and consists in the one case of sulphateof lead, and in the other of sulphate of bismuth. If either of thesebe heated under the reducing flame, it disappears in the former casewith a bluish flame, in the latter unaccompanied by any visible flame. The incrustation formed nearest to the assay consists of the oxide oflead or bismuth, and is easily recognized by its color when hot andafter cooling. There are many other metallic sulphides, which, whenheated by the blowpipe flame, cover the charcoal with a whiteincrustation, as sulphide of antimony, sulphide of zinc, and sulphideof tin. In all these cases, however, the incrustation consists of themetallic oxide alone, and either volatilizes or remains unchanged, when submitted to the oxidizing flame. 

Of the metallic chlorides there are many which, when heated oncharcoal with the blowpipe flame, are volatilized and redeposited as awhite incrustation. Among these are the chlorides of potassium, sodium, and lithium, which volatilize and cover the charcoalimmediately around the assay with a thin white film, after they havebeen fused and absorbed into the charcoal, chloride of potassium formsthe thickest deposit, and chloride of lithium the thinnest, thelatter being moreover of a greyish-white color. The chlorides ofammonium, mercury, and antimony volatilize without fusing. 

The chlorides of zinc, cadmium, lead, bismuth, and tin first fuse andthen cover the charcoal with two different incrustations, one of whichis a white volatile chloride, and the other a less volatile oxide ofthe metal. 

Some of the incrustations formed by metallic chlorides disappear witha colored flame when heated with the reducing flame; thus chloride ofpotassium affords a violet flame, chloride of sodium an orange one, chloride of lithium a crimson flame, and chloride of lead a blue one. The other metals mentioned above volatilize without coloring theflame. 

The chloride of copper fuses and colors the flame of a beautiful blue. Moreover, if a continuous blast be directed upon the salt, a part ofit is driven off in the form of white fumes which smell strongly ofchlorine, and the charcoal is covered with incrustations of threedifferent colors. That which is formed nearest to the assay is of adark grey color, the next, a dark yellow passing into brown, and themost distant of a bluish white color. If this incrustation be heatedunder the reducing flame, it disappears with a blue flame. 

Metallic iodides and bromides behave upon charcoal in a similar mannerto the chlorides. Those principally deserving of mention are thebromides and iodides of potassium and sodium. These fuse uponcharcoal, are absorbed into its pores, and volatilize in the form ofwhite fumes, which are deposited upon the charcoal at some distancefrom the assay. When the saline films so formed are submitted to thereducing flame, they disappear, coloring the flame in the same manneras the corresponding chlorides. 

4. EXAMINATIONS IN THE PLATINUM FORCEPS. 

Before the student attempts to make an examination in the platinumforceps or tongs, he should first ascertain whether or not it willact upon the platinum. If the substance to be examined shall actchemically upon the platinum, then it should be examined on thecharcoal, and the color of the flame ascertained as rigidly aspossible. The following list of substances produce the color attachedto them. 

A. VIOLET. 

 Potash, and all its compounds, with the exception of the phosphate and the borate, tinge the color of the flame violet. 

B. BLUE. 

 Chloride of copper, Intense blue. Lead, Pale clear blue. Bromide of copper, Bluish green. Antimony, Bluish green. Selenium, Blue. Arsenic, English green. 

C. GREEN. 

 Ammonia, Dark green. Boracic acid, Dark green. Copper, Dark green. Tellurium, Dark green. Zinc, Light green. Baryta Apple green. Phosphoric acid, Pale green. Molybdic acid, Apple green. Telluric acid, Light green. 

D. YELLOW. 

 Soda, Intense yellow. Water, Feeble yellow. 

E. RED. 

 Strontia, Intense crimson. Lithia, Purplish red. Potash, Violet red. Lime, Purplish red. 

The student may often be deceived in regard to the colors: forinstance, if a small splinter of almost any mineral be held at thepoint of the flame of oxidation, it will impart a very slight yellowto the flame. This is caused, doubtless, by the water contained in themineral. If the piece of platinum wire is used, and it should be wetwith the saliva, as is frequently done by the student, then the smallquantity of soda existing in that fluid will color the flame of alight yellow hue. 

A. THE VIOLET COLOR. 

The salts of potash, with the exception of the borate and thephosphate, color the flame of a rich violet hue. This color is bestdiscovered in the outer flame of the blowpipe, as is the case with allthe other colors. The flame should be a small one, with a lamp havinga small wick, while the orifice of the blowpipe must be quite small. These experiments should likewise be made in a dark room, so that thecolors may be discerned with the greatest ease. In investigating withpotash for the discernment of color, it should be borne in mind thatthe least quantity of soda will entirely destroy the violet color ofthe potash, by the substitution of its own strong yellow color. Ifthere be not more than the two hundredth part of soda, the violetreaction of the potash will be destroyed. This is likewise the casewith the presence of lithia, for its peculiar red color will destroythe violet of the potash. Therefore in making investigations with thesilicates which contain potash, the violet color of the latter canonly be discerned when they are free from soda and lithia. 

B. THE BLUE COLOR. 

(_a. _) _The Chloride of Copper. _--Any of the chlorides produce a bluecolor in the blowpipe flame, or any salt which contains chlorine willshow the blue tint, as the color in this case is referable to thechlorine itself. There are, however, some chlorides which, inconsequence of the peculiar reactions of their bases, will not producethe blue color, although in these cases the blue of the chlorine willbe very likely to blend itself with the color produced by the base. The chloride of copper communicates an intense blue to the flame, whenfused on the platinum wire. If the heat be continued until thechlorine is driven off, then the greenish hue of the oxide of copperwill be discerned. 

(_b. _) _Lead. _--Metallic lead communicates to the flame a pale bluecolor. The oxide reacts in the same manner. The lead-salts, whoseacids do not interfere with the color, impart also a fine blue to theflame, either in the platina forceps, or the crooked wire. 

(_c. _) _Bromide of Copper. _--This salt colors the flame of abluish-green color, but when the bromine is driven off, then we havethe green of the oxide of copper. 

(_d. _) _Antimony. _--This metal imparts a blue color to the blowpipeflame, but if the metal is in too small a quantity, then the color isa brilliant white. If antimony is fused on charcoal, the fused metalgives a blue color. The white sublimate which surrounds the fusedmetal, being subjected to the flame of oxidation, disappears from thecharcoal with a bluish-green color. 

(_e. _) _Selenium. _--If fused in the flame of oxidation, it imparts tothe flame a deep blue color. The incrustation upon charcoal gives tothe flame the same rich color. 

(_f. _) _Arsenic. _--The arseniates and metallic arsenic itself impartto the blowpipe flame a fine blue color, provided that there is noother body present which may have a tendency to color the flame withits characteristic hue. The sublimate of arsenious acid whichsurrounds the assay, will give the same blue flame, when dissipated bythe oxidation flame. The platinum forceps will answer for theexhibition of the color of arsenic, even though the salts bearseniates, whose bases possess the property of imparting theirpeculiar color to the flame, such as the arseniate of lime. 

C. THE GREEN COLOR. 

(_a. _) _Ammonia. _--The salts of ammonia, when heated before theblowpipe, and just upon the point of disappearing, impart to the flamea feeble though dark green color. This color, however, can only bediscerned in a dark room. 

(_b. _) _Boracic Acid. _--If any one of the borates is mixed with twoparts of a flux composed of one part of pulverized fluorspar, and fourand a half parts of bisulphate of potash, and after being melted, isput upon the coil of a platinum wire, and held at the point of theblue flame, soon after fusion takes place a dark green color isdiscerned, but it is not of long duration. The above process is thatrecommended by Dr. Turner. The green color of the borates may bereadily seen by dipping them, previously moistened with sulphuricacid, into the upper part of the blue flame, when the color can bereadily discerned. If soda be present, then the rich green of theboracic acid is marred by the yellow of the soda. Borax, or thebiborate of soda (NaO, 2BO_{3}) may be used for this latter reaction, but if it be moistened with sulphuric acid, the green of the boracicacid can then be seen. If the borates, or minerals which containboracic acid, are fused on charcoal with carbonate of potash, thenmoistened with sulphuric acid and alcohol, then the bright green ofthe boracic acid is produced, even if the mineral contains but aminute portion of the boracic acid. 

(_c. _) _Copper_. Nearly all the ores of copper and its salts, give abright green color to the blowpipe flame. Metallic copper likewisecolors the flame green, being first oxidized. If iodine, chlorine, andbromine are present, the flame is considerably modified, but theformer at least intensifies the color. Many ores containing copperalso color the flame green, but the internal portion is of a brightblue color if the compound contains lead, the latter color being dueto the lead. The native sulphide and carbonate of copper should bemoistened with sulphuric acid, while the former should be previouslyroasted. If hydrochloric acid is used for moistening the salts, thenthe rich green given by that moistened with the sulphuric acid ischanged to a blue, being thus modified by the chlorine of the acid. Silicates containing copper, if heated in the flame in the platinumforceps, impart a rich green color to the outer flame. In fact, if anysubstance containing copper be submitted to the blowpipe flame, itwill tinge it green, provided there be no other substance present toimpart its own color to the flame, and thus modify or mar that of thecopper. 

(_d. _) _Tellurium. _--If the flame of reduction is directed upon theoxide of tellurium placed upon charcoal, a green color is imparted toit. If the telluric acid be placed upon platinum wire in the reductionflame, the oxidation flame is colored green. Or if the sublimate bedissipated by the flame of oxidation, it gives a green color. Ifselenium be present, the green color is changed to a blue. 

(_e. _) _Zinc. _--The oxide of zinc, when strongly heated, gives a blueflame. This is especially the case in the reducing flame. The flame isa small one, however, and not very characteristic, as with certainpreparations of zinc the blue color is changed to a bright white. Thesoluble salts of zinc give no blue color. 

(_f. _) _Baryta. _--The soluble salts of baryta, moistened, and thensubmitted to the reduction flame, produce a green color. The saltshould be moistened, when the color will be strongly marked in theouter flame. The insoluble salts do not produce so vivid a color asthe soluble salts, and they are brighter when they have previouslybeen moistened. The carbonate does not give a strong color, but theacetate does, so long as it is not allowed to turn to a carbonate. Thechloride, when fused on the platinum wire, in the point of thereduction flame, imparts a fine green color to the oxidation flame. This tint changes finally to a faint dirty green color. The sulphateof baryta colors the flame green when heated at the point of thereduction flame. But neither the sulphate, carbonate, nor, in fact, any other salt of baryta, gives such a fine green color as thechloride. The presence of lime does interfere with the reaction ofbaryta, but still does not destroy its color. 

(_g. _) _Phosphoric Acid. _--The phosphates give a green color to theoxidation flame, especially when they are moistened with sulphuricacid. This is best shown with the platinum forceps. The green ofphosphoric, or the phosphates, is much less intense than that of theborates or boracic acid, but yet the reaction is a certain one, and issusceptible of considerable delicacy, either with the forceps, orstill better upon platinum wire. Sulphuric acid is a great aid to thedevelopment of the color, especially if other salts be present whichwould be liable to hide the color of the phosphoric acid. In thisreaction with phosphates, the water should be expelled from themprevious to melting them with sulphuric acid. They should likewise bepulverized. Should soda be present it will only exhibit its peculiarcolor after the phosphoric acid shall have been expelled; therefore, the green color of the phosphoric acid should be looked forimmediately upon submitting the phosphate to heat. 

(_h. _) _Molybdic Acid. _--If this acid or the oxide of molybdenum beexposed upon a platinum wire to the point of the reduction flame, abright green color is communicated to the flame of oxidation. Take asmall piece of the native sulphide of molybdenum, and expose it in theplatinum tongs to the flame referred to above, when the green colorcharacteristic of this metal will be exhibited. 

(_i. _) _Telluric Acid. _--If the flame of reduction is directed upon asmall piece of the oxide of tellurium placed upon charcoal, a brightgreen color is produced. Or if telluric acid be submitted to thereduction flame upon the loop of a platinum wire, it communicates tothe outer flame the bright green of tellurium. If the sublimate foundupon the charcoal in the first experiment be submitted to the blowpipeflame, the green color of tellurium is produced while the sublimate isvolatilized. If selenium be present the green color is changed to adeep blue one. 

D. YELLOW. 

The salts of soda all give a bright yellow color when heated in theplatinum loop in the reduction flame. This color is very persistent, and will destroy the color of almost any other substance. Everymineral of which soda is a constituent, give this bright orange-yellowreaction. Even the silicate of soda itself imparts to the flame ofoxidation the characteristic yellow of soda. 

E. RED. 

(_a. _) _Strontia. _--Moisten a small piece of the chloride ofstrontium, put it in the platinum forceps and submit it to the flameof reduction, when the outer flame will become colored of an intensered. If the salt of strontia should be a soluble one, the reaction isof a deeper color than if an insoluble salt is used, while the coloris of a deeper crimson if the salt is moistened. If the salt be asoluble one, it should be moistened and dipped into the flame, whileif it be an insoluble salt, it should be kept dry and exposed beyondthe point of the flame. The carbonate of strontia should be moistenedwith hydrochloric acid instead of water, by which its color similatesthat of the chloride of strontium when moistened with water. Inconsequence of the decided red color which strontia communicates toflame, it is used by pyrotechnists for the purpose of making their"crimson fire. "

(_b. _) _Lithia. _--The color of the flame of lithia is slightlyinclined to purple. The chloride, when placed in the platinum loop, gives to the outer flame a bright red color, sometimes with a slighttinge of purple. Potash does not prevent this reaction, although itmay modify it to violet; but the decided color of soda changes the redof lithia to an orange color. If much soda be present, the color ofthe lithia is lost entirely. The color of the chloride of lithium maybe distinctly produced before the point of the blue flame, and itsdurability may be the means of determining it from that of lithium, as the latter, under the same conditions, is quite evanescent. Theminerals which contain lithia, frequently contain soda, and thus thelatter destroys the color of the former. 

(_c. _) _Potash. _--The salts of potash, if the acid does not interfere, give a purplish-red color before the blowpipe; but as the color ismore discernibly a purple, we have classed it under that color. 

(_d. _) _Lime. _--The color of the flame of lime does not greatly differfrom that of strontia, with the exception that it is not so decided. Arragonite and calcareous spar, moistened with hydrochloric acid, andtried as directed for strontia, produce a red light, not unlike thatof strontia. The chloride of calcium gives a red tinge, but not nearlyso decided as the chloride of strontium. The carbonate of lime willproduce a yellowish flame for a while, until the carbonic acid isdriven off, when the red color of the lime may be discerned. 

If the borate or phosphate of lime be used, the green color of theacids predominates over the red of the lime. Baryta also destroys thered color of the lime, by mixing its green color with it. There is butone silicate of lime which colors the flame red, it is the varietytermed tabular spar. 

5. EXAMINATIONS IN THE BORAX BEAD. 

In order to examine a substance in borax, the loop of the platinumwire should, after being thoroughly cleaned, and heated to redness, bequickly dipped into the powdered borax, and then quickly transferredto the flame of oxidation, and there fused. If the bead is not largeenough to fill the loop of the wire, it must be subjected again to thesame process. By examining the bead, both when hot and cold, byholding it up against the light, it can be soon ascertained whether itis free from dirt by the transparency, or the want of it, of the bead. 

In order to make the examination of a substance, the bead should bemelted and pressed against it, when enough will adhere to answer thepurpose. This powder should then be fused in the oxidation flame untilit mixes with, and is thoroughly dissolved by the borax bead. 

The principal objects to be determined now are: the color of the boraxbead, both when heated and when cooled; also the rapidity with whichthe substance dissolves in the bead, and if any gas is eliminated. 

If the color of the bead is the object desired, the quantity of thesubstance employed must be very small, else the bead will be so deeplycolored, as in some cases to appear almost opaque, as, for instance, in that of cobalt. Should this be the case, then, while the bead isstill red hot, it should be pressed flat with the forceps; or it may, while soft, be pulled out to a thin thread, whereby the color can bedistinctly discovered. 

Some bodies, when heated in the borax bead, present a clear bead bothwhile hot and cold; but if the bead be heated with the intermittentflame, or in the flame of reduction, it becomes opalescent, opaque ormilk-white. The alkaline earths are instances of this kind ofreaction, also glucina oxide of cerium, tantalic and titanic acids, yttria and zirconia. But if a small portion of silica should bepresent, then the bead becomes clear. This is likewise the case withsome silicates, provided there be not too large a quantity present, that is: over the quantity necessary to saturate the borax, for, inthat case, the bead will be opaque when cool. 

If the bead be heated on charcoal, a small tube or cavity must bescooped out of the charcoal, the bead placed in it, and the flame ofreduction played upon it. When the bead is perfectly fused, it istaken up between the platinum forceps and pressed flat, so that thecolor may be the more readily discerned. This quick cooling alsoprevents the protoxides, if there be any present, from passing into ahigher degree of oxidation. 

The bead should first be submitted to the oxidation flame, and anyreaction carefully observed. Then the bead should be submitted to theflame of reduction. It must be observed that the platinum forcepsshould not be used when there is danger of a metallic oxide beingreduced, as in this case the metal would alloy with the platinum andspoil the forceps. In this case charcoal should be used for thesupport. If, however, there be oxides present which are not reduced bythe borax, then the platinum loop may be used. Tin is frequently usedfor the purpose of enabling the bead to acquire a color for an oxidein the reducing flame, by its affinity for oxygen. The oxide, thusbeing reduced to a lower degree of oxidation, imparts its peculiartinge to the bead as it cools. 

The arsenides and sulphides, before being examined, should be roasted, and then heated with the borax bead. The arsenic of the former, itshould be observed, will act on the glass tube in which thesublimation is proceeding, if the glass should contain lead. 

It should be recollected that earths, metallic oxides, and metallicacids are soluble in borax, except those of the easily reduciblemetals, such as platinum or gold, or of mercury, which too readilyvaporize. Also the metallic sulphides, after the sulphur has beendriven off. Also the salts of metals, after their acids are driven offby heat. Also the nitrates and carbonates, after their acids aredriven off during the fusion. Also the salts of the halogens, such asthe chlorides, iodides, bromides, etc. , of the metals. Also thesilicates, but with great tardiness. Also the phosphates and boratesthat fuse in the bead without suffering decomposition. The metallicsulphides are insoluble in borax, and many of the metals in the purestate. 

There are many substances which give clear beads with borax both whilehot and cold, but which, upon being heated with the intermittentoxidation flame, become enamelled and opaque. The intermittent flamemay be readily attained, not by varying the force of the air from themouth, but by raising and depressing the bead before the point of thesteady oxidating flame. The addition of a little nitrate of potashwill often greatly facilitate the production of a color, as itoxidizes the metal. The hot bead should be pressed upon a smallcrystal of the nitrate, when the bead swells, intumesces, and thecolor is manifested in the surface of the bead, 6. EXAMINATIONS IN MICROCOSMIC SALT. 

Microcosmic salt is a better flux for many metallic oxides than borax, as the colors are exhibited in it with more strength and character. Microcosmic salt is the phosphate of soda and ammonia. When it isignited it passes into the biphosphate of soda, the ammonia beingdriven off. This biphosphate of soda possesses an excess of phosphoricacid, and thus has the property of dissolving a great number ofsubstances, in fact almost any one, with the exception of silica. Ifthe substances treated with this salt consist of sulphides orarsenides, the bead must be heated on charcoal. But if the substanceexperimented upon consists of earthly ingredients or metallic oxides, the platinum wire is the best. If the latter is used a few additionalturns should be given to the wire in consequence of the greaterfluidity of the bead over that of borax. The microcosmic salt beadpossesses the advantage over that of borax, that the colors of manysubstances are better discerned in it, and that it separates theacids, the more volatile ones being dissipated, while the fixed onescombine with a portion of the base equally with the phosphoric acid, or else do not combine at all, but float about in the bead, as is thecase particularly with silicic acid. Many of the silicates give withborax a clear bead, while they form with microcosmic salt anopalescent one. 

It frequently happens, that if a metallic oxide will not give itspeculiar color in one of the flames, that it will in the other, as thedifference in degree with which the metal is oxidized often determinesthe color. If the bead is heated in the reducing flame, it is wellthat it should be cooled rapidly to prevent a reoxidation. Reductionis much facilitated by the employment of metallic tin, whereby theprotoxide or the reduced metal may be obtained in a comparativelybrief time. 

The following tables, taken from Plattner and Sherer, will present thereactions of the metallic oxides, and some of the metallic acids, insuch a clear light, that the student cannot very easily be led astray, if he gives the least attention to them. It frequently happens that atabular statement of reactions will impress facts upon the memory whenlong detailed descriptions will fail to do so. It is for this purposethat we subjoin the following excellent tables. 

 * * * * *

TABLE I. 

 A. BORAX. 1. Oxydizing flame. 2. Reducing "

 B. MICROCOSMIC SALT. 1. Oxydizing flame. 2. Reducing "

A. BORAX

1. Oxydizing flame

--------------------------------------------------------------------------Color of Bead. --+----------------------------------------------------------------------- | Substances which produce this color +--------------------------------------+-------------------------------- | in the hot bead. | in the cold bead. --+--------------------------------------+--------------------------------Colorless-----------------------------------------+-------------------------------- | Silica \ | Silica | Alumina \ | Alumina _ | Oxide of Tin | | Oxide of Tin \ | Telluric Acid | | Telluric Acid \ | Baryta | | Baryta \ | Strontia | | Strontia | | Lime | | Lime | | Magnesia | | Magnesia | | Glucina | In all | Glucina | | Yttria } proportions. | Yttria | | Zirconia | | Zirconia | | Thoria | | Thoria |With | Oxide of Lanthanum | | Oxide of Lanthanum |intermittent | | | " " Silver }flame | Tantalic Acid | | Tantalic Acid |opaque | Niobic " | | Niobic " |white. | Pelopic " / | Pelopic " | | Titanic " _/ | Titanic " | | _ | | | Tungstic " \ In small | Tungstic " | | Molybdic " \ quantity | Molybdic " | | Oxide of Zinc | only. | Oxide of Zinc / | " " Cadmium } | " " Cadmium_/ | " " Lead | In large | " " Lead | " " Bismuth / quantity | " " Bismuth | " " Antimony / yellow. | " " Antimony--+-----------+--------------------------+--------------------------------Yellow, orange-red and reddish-brown. --+-----------+--------------------------+-------------------------------- | _ | | Titanic Acid, yellow \ | | Tungstic Acid, yellow \ | | Molybdic Acid, dark yellow|when in | | Oxide of Zinc, pale-yellow|large | | Oxide of Cadmium, }quantity. | | pale-yellow |Otherwise | | Oxide of Lead, yellow |colorless. | | Oxide of Bismuth, orange / | | Oxide of Antimony, yellow/ | | Oxide of Cerium, red | Oxide of Cerium with interm. | Oxide of Iron, dark red | flame opaque white. | Oxide of Uranium, red | Oxide of Iron, yellow | Oxide of Silver | Oxide of Uranium with interm. | | flame opaque yellow. | | Oxide of Silver in large | | proportion, with interm. | | flame yellow. | Vanadic Acid, yellow | Vanadic Acid, yellow. | Oxide of Chromium, dark-red | Oxide of Nickel, | | reddish-brown. | | Oxide of Manganese, red to | | violet. --+--------------------------------------+--------------------------------Violet or Amethyst. --+--------------------------------------+-------------------------------- | Oxide of Nickel | | " " Manganese | Oxide of Didymium. | " " Didymium |--+--------------------------------------+--------------------------------Blue. --+--------------------------------------+-------------------------------- | Oxide of Cobalt | Oxide of Cobalt. | | " Copper, blue to | | greenish-blue. --+--------------------------------------+--------------------------------Green. --+--------------------------------------+-------------------------------- | Oxide of Copper | Oxide of Chromium, with | | yellowish tinge. --+--------------------------------------+--------------------------------

A. BORAX

2. Reducing flame

--+--------------------------------------+--------------------------------Color of Bead. --+----------------------------------------------------------------------- | Substances which produce this color +--------------------------------------+-------------------------------- | in the hot bead. | in the cold bead. --+--------------------------------------+--------------------------------Colorless--+--------------------------------------+-------------------------------- | Silica | Silica | Alumina | Alumina | Oxide of Tin | Oxide of Tin _ | Baryta | Baryta \ | Strontia | Strontia \ | Lime | Lime | | Magnesia | Magnesia |With | Glucina | Glucina |intermittent | Yttria | Yttria }flame | Zirconia | Zirconia |opaque-white. | Thoria | Thoria only when | | | saturated | | Oxide of Lanthanum | Oxide of Lanthanum | | " " Cerium | " " Cerium / | Tantalic Acid | Tantalic Acid _/ | Oxide of Didymium | Oxide of Didymium | " " Manganese | " " Manganese | _ | _ | Niobic Acid \ In small | Niobic Acid \ In small | Pelopic " } proportions. | Pelopic " } proportions. | _/ | _/ | _ | _ | Oxide of Silver \ | Oxide of Silver \ After | " " Zinc \ After long | " " Zinc \ long | " " Cadmium | continued | " " Cadmium | continued | " " Lead } blowing. | " " Lead } blowing. | " " Bismuth | Otherwise | " " Bismuth | Otherwise | " " Antimony| grey. | " " Antimony | grey. | " " Nickel / | " " Nickel / | Telluric Acid _/ | Telluric Acid _/--+--------------------------------------+--------------------------------Yellow to brown. --+--------------------------------------+-------------------------------- | Titanic Acid | Titanic Acid. | Tungstic " | Tungstic " | Molybdic " | Molybdic " | Vanadic " |--+--------------------------------------+--------------------------------Blue. --+--------------------------------------+-------------------------------- | Oxide of Cobalt. | Oxide of Cobalt. | | Titanic Acid with intermittent | | flame opaque-blue. --+--------------------------------------+--------------------------------Green. --+--------------------------------------+-------------------------------- | Oxide of Iron | Oxide of Iron, bottle-green. | " " Uranium | Oxide of Uranium, bottle- | " " Chromium | green. | | Oxide of Chromium, emerald- | | green. | | Vanadic Acid, emerald-green. --+--------------------------------------+--------------------------------Opaque-grey. (The opacity generally becomes distinct during cooling. )--+--------------------------------------+-------------------------------- | _ | | Oxide of Silver \ | Oxide of Silver. _ | " " Zinc \ After | " " Zinc \ After | " " Cadmium | short | " " Cadmium \short | " " Lead } blowing. | " " Lead |blowing. | " " Bismuth | Otherwise | " " Bismuth }Otherwise | " " Antimony| colorless. | " " Antimony |colorless. | " " Nickel / | " " Nickel / | Telluric Acid _/ | Telluric Acid _/ | _ | _ | Niobic Acid \ After long | Niobic Acid\ After long | Pelopic " | continued blowing | Pelopic " | continued | } and in | } blowing and | | considerable | | in considerable | _/ proportion. | _/ proportion. | |--+--------------------------------------+--------------------------------Opaque red and reddish-brown. --+--------------------------------------+-------------------------------- | Oxide of Copper | Oxide of Copper. --+--------------------------------------+--------------------------------

B. MICROCOSMIC SALT. 

1. Oxydizing flame. 

--+--------------------------------------+--------------------------------Color of Bead. --+----------------------------------------------------------------------- | Substances which produce this color +--------------------------------------+-------------------------------- | in the hot bead. | in the cold bead. --+--------------------------------------+--------------------------------Colorless--+--------------------------------------+-------------------------------- | _ | | Silica (only \ | Silica | slightly soluble)\ | | Alumina | | Alumina | Oxide of Tin | | Oxide of Tin _ | Telluric Acid | | Telluric Acid \ | Baryta | | Baryta \ | Strontia | | Strontia |With | Lime | In all | Lime |intermittent | Magnesia } proportions. | Magnesia }flame | Glucina | | Glucina |opaque | Yttria | | Yttria |white. | Zirconia | | Zirconia | | Thoria | | Thoria / | Oxide of Lanthanum | | Oxide of Lanthanum/ | | | " " Cerium | Niobic Acid / | Niobic Acid | Pelopic " _/ | Pelopic " | Tantalic " | Tantalic " | Titanic " | Titanic " | Tungstic " _ | Tungstic " | Oxide of Zinc \ In small | Oxide of Zinc | " " Cadmium \ quantity only. | " " Cadmium | " " Lead } In large | " " Lead | " " Bismuth | quantity | " " Bismuth | " " Antimony / yellow. | " " Antimony | _/ |--+--------------------------------------+--------------------------------Yellow, orange, red and brown. --+--------------------------------------+-------------------------------- | Tantalic Acid _ | | Titanic " \ | | Tungstic " | | | Oxide of Zinc | In large | | " " Cadmium } quantity. | | " " Lead | | | " " Bismuth | | | " " Antimony _/ | | " " Silver | Oxide of Silver. | " " Cerium | | " " Iron | Oxide of Iron. | " " Nickel | " " Nickel. | " " Uranium | " " Uranium, | | yellowish-green. | Vanadic Acid | Vanadic Acid. | Oxide of Chromium |--+--------------------------------------+--------------------------------Violet or Amethyst. --+--------------------------------------+-------------------------------- | Oxide of Manganese | Oxide of Manganese. | " " Didymium | " " Didymium. --+--------------------------------------+--------------------------------Blue. --+--------------------------------------+-------------------------------- | Oxide of Cobalt | Oxide of Cobalt | | Oxide of Copper, to | | greenish-blue. --+--------------------------------------+--------------------------------Green. --+--------------------------------------+-------------------------------- | Molybdic Acid, yellowish-green | Molybdic Acid, yellowish-green. | Oxide of Copper | Oxide of Uranium, | | yellowish-green. | | Oxide of Chromium, | | emerald-green. --+--------------------------------------+--------------------------------

B. MICROCOSMIC SALT. 

2. Reducing flame. 

--+--------------------------------------+--------------------------------Color of Bead. --+----------------------------------------------------------------------- | Substances which produce this color +--------------------------------------+--------------------------------- | in the hot bead. | in the cold bead. --+--------------------------------------+--------------------------------Colorless--+--------------------------------------+-------------------------------- | Silica (only slightly soluble) | Silica (only slightly soluble). | Alumina | Alumina. | Oxide of Tin | Oxide of Tin. _ | Baryta | Baryta \ | Strontia | Strontia \ | Lime | Lime | | Magnesia | Magnesia |With an | Glucina | Glucina }intermittent | Yttria | Yttria |flame | Zirconia | Zirconia |opaque- | Thoria | Thoria only when |white. | | saturated / | Oxide of Lanthanum | Oxide of Lanthanum/ | " " Cerium | " " Cerium. | " " Didymium | " " Didymium. | " " Manganese | " " Manganese. | Tantalic Acid _ | Tantalic Acid. | Oxide of Silver \ | Oxide of Silver _ | " " Zinc \ | " " Zinc \ After | " " Cadmium | After long | " " Cadmium \ long | " " Lead } continued | " " Lead | continued | " " Bismuth | blowing. | " " Bismuth } blowing. | " " Antimony | Otherwise grey. | " " Antimony | Otherwise | " " Nickel / | " " Nickel / grey. | Telluric Acid _/ | Telluric Acid _/--+--------------------------------------+--------------------------------Yellow, red, and brown. --+--------------------------------------+-------------------------------- | Oxide of Iron, red | Oxide of Iron. | Titanic Acid, yellow | | Pelopic Acid, brown | Pelopic Acid. | Ferruginous Titanic Acid, blood red | Ferruginous Titanic Acid. | " Niobic " " | " Niobic " | " Pelopic " " | " Pelopic " | " Tungstic " " | " Tungstic " | Vanadic Acid, brownish | | Oxide of Chromium, reddish |--+--------------------------------------+--------------------------------Violet or Amethyst. --+--------------------------------------+-------------------------------- | Niobic Acid in large proportion | Niobic Acid in large proportion. | | Titanic Acid. --+--------------------------------------+--------------------------------Blue. --+--------------------------------------+-------------------------------- | Oxide of Cobalt | Oxide of Cobalt. | Tungstic Acid | Tungstic Acid. | Niobic Acid in very large proportion. | Niobic Acid in very large | | proportion. --+--------------------------------------+--------------------------------Green. --+--------------------------------------+-------------------------------- | Oxide of Uranium | Oxide of Uranium. | Molybdic Acid | Molybdic Acid. | | Vanadic " | | Oxide of Chromium. --+--------------------------------------+--------------------------------Opaque-grey. (The opacity generally becomes distinct during cooling. )--+--------------------------------------+-------------------------------- | Oxide of Silver | Oxide of Silver. | " " Zinc | " " Zinc. | " " Cadmium | " " Cadmium. | " " Lead | " " Lead. | " " Bismuth | " " Bismuth. | " " Antimony | " " Antimony. | " " Nickel | " " Nickel. | Telluric Acid | Telluric Acid. --+--------------------------------------+--------------------------------Opaque-red and reddish brown. --+--------------------------------------+-------------------------------- | Oxide of Copper | Oxide of Copper. --+--------------------------------------+--------------------------------

 * * * * *

TABLE II. 

Metallic Oxides

1. Oxide of Cerium, C^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves into a red or dark yellow glass (similar to that produced by iron). During cooling, the color diminishes in the intensity and becomes finally yellow. If much oxide be dissolved, an opaque bead may be obtained with an intermittent flame, and a still larger quantity renders it opaque spontaneously. 

 in the reducing flame. 

 The color of the bead becomes paler, so that a bead, which is yellow in the oxidizing flame, is rendered colorless. With a large quantity of oxide the bead becomes white and crystalline on cooling. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. During the process of cooling the color entirely disappears. 

 in the reducing flame. 

 Both, when hot and cold, the bead is colorless, by which character oxide of cerium may be distinguished from oxide of iron. The glass remains clear even when containing a large quantity of the oxide. 

 * * * * *

2. Oxide of Lanthanum, LaO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves into a colorless glass, which, when sufficient oxide is present, may be rendered opaque with an intermittent flame, and becomes so spontaneously on cooling, when a still larger amount is dissolved. 

 in the reducing flame. 

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. 

 in the reducing flame. 

 No reaction. 

 * * * * *

3. Oxide of Didymium, DO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame:

 Dissolves to a clear dark amethystine glass. 

 in the reducing flame. 

 No reaction. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. 

 in the reducing flame. 

 No reaction. 

 * * * * *

4. Oxide of Manganese, Mn^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Affords an intense amethyst color, which on cooling becomes violet. A large quantity of the oxide produces an apparently black bead, which however, if pressed flat, is seen to be transparent. 

 in the reducing flame. 

 The colored bead becomes colorless. With a large amount of the oxide, this reaction is best obtained upon charcoal, and is facilitated by the addition of tin foil. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 With a considerable quantity of oxide an amethyst color is obtained, but never so dark as in borax. With but little oxide a colorless bead is obtained, in which, however, the amethyst-color may be brought out by adding a little nitre. While the bead is kept fused, it froths and gives off bubbles of gas. 

 in the reducing flame. 

 The colored bead immediately loses its color, either on platinum wire or on charcoal. After the reduction the fluid bead remains still. 

 * * * * *

5. Oxide of Iron, Fe^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 With a small proportion of oxide, the glass is of a yellow color, while warm, and colorless when cold; with a larger proportion, red, while warm, and yellow, when cold; and with a still larger amount, dark-red, while warm, and dark-yellow, when cold. 

 in the reducing flame. 

 Treated alone on platinum wire, the glass becomes of a bottle-green color (F^{3}O^{4}), and if touched with tin, it becomes of a pale sea-green. On charcoal with tin, it assumes at first a bottle-green color, which by continued blowing changes to a sea-green (FeO). 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 With a certain amount of oxide, the glass is of a yellowish-red color, which on cooling changes to yellow, then green, and finally becomes colorless. With a large addition of oxide, the color is, when warm, dark red, and passes, while cooling, into brownish-red, dark green, and finally brownish-red. During the cooling process, the colors change more rapidly than with borax. 

 in the reducing flame. 

 With a small proportion of oxide there is no reaction. With a larger amount the bead is red, while warm, and becomes on cooling successively yellow, green, and russet. With the addition of tin the glass becomes, during cooling, first green and then colorless. 

 * * * * *

6. Oxide of Cobalt, CoO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame:

 Colors the glass of an intense smalt blue both whilst hot and when cold. When much oxide is present, the color is so deep as to appear black. 

 in the reducing flame:

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax, but less intensively colored. During cooling the color becomes somewhat paler. 

 in the reducing flame. 

 As in the oxidizing flames. 

 * * * * *

7. Oxide of Nickel, NiO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Colors intensely. A small amount of oxide affords a glass which, while warm, is violet, and becomes of a pale reddish-brown on cooling. A larger addition produces a dark violet color in the warm and reddish-brown in the cold bead. 

 in the reducing flame. 

 The oxide is reduced and the metallic particles give the bead a turbid grey appearance. If the blast be continued the metallic particles fall together without fusing, and the glass becomes colorless. This reaction is readily obtained with tin upon charcoal, and the reduced nickel fuses to a bead with the tin. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves into a reddish glass which becomes yellow on cooling. With a large addition of the oxide, the glass is brownish while hot, and orange when cold. 

 in the reducing flame. 

 On platinum wire the nickeliferous bead undergoes no change. Treated with tin upon charcoal, it becomes at first opaque and grey, and after long continued blowing the reduced nickel forms a bead, and the glass remains colorless. 

 * * * * *

8. Oxide of Zinc, ZnO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves easily into a clear colorless glass, which, when much oxide is present, may be rendered opaque and flocculent by an intermittent flame, and becomes so spontaneously with a still larger addition. When a considerable quantity is dissolved, a glass is obtained which is pale yellow, while hot, and colorless when cold. 

 in the reducing flame. 

 On platinum wire the saturated glass becomes at first opaque and grey, but by a sustained blast is again rendered clear. On charcoal the oxide is gradually reduced; the metal is volatilized and in crusts the charcoal with oxide. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. 

 in the reducing flame. 

 As with borax. 

 * * * * *

9. Oxide of Cadmium, CdO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 When in very large proportion, dissolves to a clear yellow glass, which becomes nearly colorless on cooling. When the oxide is present in any considerable quantity, the glass can be rendered opaque with an intermittent flame, and, with a larger addition, it becomes so spontaneously on cooling. 

 in the reducing flame. 

 Upon charcoal ebullition takes place and the oxide is reduced. The metallic cadmium is volatilized and incrusts the charcoal with its characteristic deep yellow oxide. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 When in very large proportion dissolves to a clear glass, having a yellow tinge, while hot, which disappears on cooling, and when perfectly saturated, becomes milk-white. 

 in the reducing flame. 

 On charcoal the oxide is slowly and imperfectly reduced. The reduced metal forms the characteristic incrustation on the charcoal, but the is thin and does not exhibit its color clearly until quite cold. The addition of tin hastens the reaction. 

 * * * * *

10. Oxide of Lead, PbO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear yellow glass, which loses its color upon cooling, and when containing much oxide can be rendered dull under an intermittent flame. With a still larger addition of oxide it becomes opaline yellow on cooling. 

 in the reducing flame. 

 The plumbiferous glass spreads out on charcoal, becomes turbid, bubbles up, until the whole of the oxide is reduced, when it again becomes clear. It is, however, difficult to bring the lead together into a bead. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax, but a larger addition of oxide, required to produce a yellow color in the warm bead. 

 in the reducing flame. 

 On charcoal the plumbiferous glass becomes grey and dull. With an over dose of oxide a part is volatilized and forms an incrustation on the charcoal beyond the bead. The addition of tin does not render the glass opaque, but somewhat more dull and grey than in its absence. 

 * * * * *

11. Oxide of Tin, SnO^{2}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 In small quantity dissolves slowly into a clear colorless glass, which, when cold, remains clear, and cannot be rendered opaque with an intermittent flame. If a saturated bead, which has been allowed to cool, be reheated to incipient redness, it loses its rounded form and exhibits imperfect crystallization. 

 in the reducing flame. 

 A glass containing but little oxide undergoes no change. If much of the latter be present, a part may be reduced upon charcoal. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 In small quantity dissolves very slowly to a colorless glass, which remains clear on cooling. 

 in the reducing flame. 

 The glass undergoes no change, either on charcoal or platinum wire. 

 * * * * *

12. Oxide of Bismuth, BiO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear glass which with a small amount of the oxide is yellow, while warm, and becomes colorless on cooling. With a larger addition, the glass is, in the hot state, of a deep orange color, which changes to yellow and finally becomes opaline in process of cooling. 

 in the reducing flame. 

 A glass becomes at first grey and turbid, then begins to effervesce, which action continues during the reduction of the oxide, and it finally becomes perfectly clear. If tin be added, the glass becomes at first grey from the reduced bismuth, but, when the metal is collected into a bead, the glass is again clear and colorless. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves in small quantity to a clear colorless glass. A larger addition affords a glass which, while warm, is yellow, and becomes colorless on cooling. When in sufficient proportion the glass may be rendered opaque under an intermittent flame, and a still larger addition of oxide renders the bead spontaneously opaque on cooling. 

 in the reducing flame. 

 On charcoal, and especially with the addition of tin, the glass remains colorless and clear, while warm, but becomes on cooling of a dark grey color and opaque. 

 * * * * *

13. Oxide of Uranium, U^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Behaves similarly to oxide of iron, with the exception that the color of the former is somewhat paler. When sufficiently saturated, the glass may be rendered of an opaque yellow by an intermittent flame. 

 in the reducing flame. 

 Affords the same color as the oxide of iron. The green glass obtained in this flame, if sufficiently saturated, can be rendered black by an intermittent flame, but it has under these circumstances no enameline appearance. On charcoal, with the addition of tin, the glass takes a dark green color. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear yellow glass, which assumes a yellowish-green color on cooling. 

 in the reducing flame. 

 The glass assumes a beautiful green color, which becomes more brilliant as the bead cools. The addition of tin upon charcoal produces no further change. 

 * * * * *

14. Oxide of Copper, CuO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Produces an intense coloration. If in small quantity, the glass is green, while warm, and becomes blue on cooling. If in large proportion, the green color is so intense as to appear black. When cool, this becomes paler, and changes to a greenish blue. 

 in the reducing flame. 

 If not too saturated, the cupriferous glass soon becomes nearly colorless, but immediately on solidifying assumes a red color and becomes opaque. By long continued blowing on charcoal, the copper in the bead is reduced and separates out as a small metallic bead, leaving the glass colorless. With the addition of tin, the glass becomes of an opaque dull-red on cooling. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 With an equal proportion of oxide, this salt is not so strongly colored as borax. A small amount imparts a green color in the warm and a blue in the cold. With a very large addition of oxide, the glass is opaque in the hot state, and after cooling of a greenish-blue. 

 in the reducing flame. 

 A tolerably saturated glass assumes a dark green color under a good flame, and on cooling becomes of an opaque brick-red, the moment it solidifies. A glass containing but a small proportion of the oxide becomes equally red and opaque on cooling, if treated with tin upon charcoal. 

 * * * * *

15. Oxide of Mercury, HgO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 No reaction. 

 in the reducing flame. 

 No reaction. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 No reaction. 

 in the reducing flame. 

 No reaction. 

 * * * * *

16. Oxide of Silver, AgO. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 The oxide is partly dissolved and partly reduced. In small quantity, it colors the glass yellow while warm, the color disappearing on cooling. In larger quantity, the glass is yellow while warm, but during cooling becomes paler to a certain point, and then again deeper. If reheated slightly, the glass becomes opalescent. 

 in the reducing flame. 

 On charcoal the argentiferous glass becomes at first grey from the reduced metal, but afterwards, when the silver is collected into a bead, it becomes clear and colorless. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Both the oxide and the metal afford a yellowish glass, which, when containing much oxide becomes opaline, exhibiting a yellow color by daylight and a red one by artificial light. 

 in the reducing flame. 

 As in borax. 

 * * * * *

17. Oxide of Platinum, PtO^{2}. 18. Oxide of Palladium, PdO^{2}. 19. Oxide of Rhodium, R^{2}O^{3}. 20. Oxide of Iridium, Ir^{2}O^{3}. 21. Oxide of Ruthenium, Ru^{2}O^{9}. 22. Oxide of Osmium OsO^{2}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Are reduced without being dissolved. The reduced metal, being infusible, cannot however be collected into a bead. 

 in the reducing flame. 

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As in borax. 

 in the reducing flame. 

 As in borax. 

 * * * * *

23. Oxide of Gold, Au^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Is reduced without being dissolved and can be collected into a bead on charcoal. 

 in the reducing flame. 

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As in borax. 

 in the reducing flame. 

 As in borax. 

 * * * * *

24. Titanic Acid, TiO^{2}

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear glass which, when but little acid is present, is colorless, but when in larger proportion, yellow, and, on cooling, colorless. When sufficiently saturated, it may be rendered opaque with an intermittent flame, and with a still larger addition of the acid becomes so spontaneously on cooling. 

 in the reducing flame. 

 In small proportion, it renders the glass yellow in larger quantity dark-yellow or brown. A saturated bead assumes a blue enamel-like appearance under an intermittent flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear glass, which, when sufficiently saturated, is yellow white hot, and becomes colorless on cooling. 

 in the reducing flame. 

 The glass obtained in the oxidizing glame becomes yellow in the hot state, but on cooling assumes a beautiful violet color. If too saturated, this color is so deep as to appear opaque, but is not enameline. If the titanic acid contains iron, the glass becomes on cooling of a brownish-yellow or red color. The addition of tin neutralizes the iron, and the glass then becomes violet. 

 * * * * *

25. Tantalic Acid, TaO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear colorless glass, which, when sufficiently saturated, may be rendered opaque with an intermittent flame, and with a larger addition of the acid becomes spontaneously enameline on cooling. 

 in the reducing flame. 

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear glass, which, when it contains a large proportion of the acid, is yellow while warm, but becomes colorless on cooling. 

 in the reducing flame. 

 The glass obtained in the oxidizing flame undergoes no change, nor does it, according to _H. Rose_, alter by the addition of sulphate of iron. 

 * * * * *

26. Niobic Acid, Ni^{2}O{3}

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Behaves in a similar manner to tantalic acid, but the glass requires a very large dose of the acid to render it opaque under an intermittent flame. With an increased amount of the acid, the glass is clear and yellow, while warm, but becomes on cooling turbid, and when quite cold is white. 

 in the reducing flame. 

 The glass obtained in the oxidizing flame and which has become opalescent on cooling, is rendered clear in the reducing flame. With a larger addition of the acid, it becomes dull, and of a bluish-grey color on cooling, and a still larger amount of renders it opaque and bluish grey. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves in large quantities to a clear colorless glass. 

 in the reducing flame. 

 If the acid be not present in too large a proportion, the glass remains unchanged. An additional amount of the acid renders it violet, and a still larger quantity affords a beautiful pure blue color, similar to that produced by tungstic acid. If to such a bead some sulphate of iron be added, the glass becomes blood-red. The addition of peroxide of iron renders the glass deep yellow while warm, the color becomes paler on cooling. 

 * * * * *

27. Pelopic Acid, Pp^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Behaves similarly to the preceding. 

 in the reducing flame. 

 A bead containing sufficient of the acid to render it spontaneously opaque on cooling, has a greyish color. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves even in large quantity to a colorless glass. 

 in the reducing flame. 

 With sufficient dose of the acid, the bead becomes brown with a violet tinge. This reaction is readily obtained upon charcoal. Sulphate of iron renders the bead blood-red. 

 * * * * *

28. Oxide of Antimony, SbO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Even when in large proportion, dissolves to a clear glass, which is yellow when warm, but almost entirely loses its color on cooling. On charcoal, the antimonious acid may be almost expelled, so that tin produces no further change. 

 in the reducing flame. 

 A bead, that has only been treated for a short time in the oxidizing flame, when submitted to the reducing flame becomes grey and turbid from the reduced antimony. This soon volatizes and the glass again becomes clear. The addition of tin renders the glass ash-grey or black, according to the amount of oxide it contains. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves with ebullition to a glass of a pale yellow color while warm. 

 in the reducing flame. 

 On charcoal, the saturated glass becomes at first dull, but as soon as the reduced antimony is volatilized, it again becomes clear. With tin, the glass is at first rendered grey by the reduced antimony, but by continued blowing is restored to clearness. Even when the glass contains but little oxide, tin produces this reaction. 

 * * * * *

29. Tungstic Acid, WO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily to a clear colorless glass. In large proportion it renders the borax yellow, while warm, and with a still greater addition the bead may be made opaque with an intermittent flame. If more be then added, this reaction takes place spontaneously. 

 in the reducing flame. 

 When the oxide is present in small quantity, the glass undergoes no change. With a larger proportion, the glass is deep yellow while warm, and yellowish-brown when cold. This reaction takes place upon charcoal, with a small quantity of the acid. Tin produces a dark coloration, when the acid is not present in too great a quantity. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear glass, which, when saturated, is yellow in the hot state. 

 in the reducing flame. 

 The glass is of a pure blue. If the tungstic acid contain iron, the glass becomes blood-red on cooling, similar to titanic acid. In this case, tin restores the blue color, or, if iron be in considerable quantity, renders it green. 

 * * * * *

30. Molydbic Acid, MO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves readily and in large quantity. When but little is dissolved, the glass is yellow while hot and colorless when cold. When in larger quantity yellow while warm and opaline when cold, and a further addition of acid renders it yellow when warm, the color, on cooling, changing first to a pale enamel blue, and then to an enamel white. 

 in the reducing flame. 

 The glass, which has been treated in the oxidizing flame, becomes, when the acid is not present in too large a quantity, brown, and when in large quantity, perfectly opaque. In a strong flame, oxide of molybdenum is formed which is visible in the yellow glass in the form of black flakes. If the glass appear opaque, it should be flattened with the forceps. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear glass, which, when sufficient acid is present, is of a yellowish-green color when warm, and becomes nearly colorless on cooling. On charcoal, the glass becomes dark, and when cool has a beautiful green color. 

 in the reducing flame. 

 The glass becomes of a bottle-green color, which on cooling, changes to a brilliant green, similar to that produced by oxide of chromium. The reaction on charcoal is precisely similar. Tin renders the color somewhat darker. 

 * * * * *

31. Vanadic Acid, VaO^{8}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear glass, which is colorless when only a small quantity of acid is present, and yellow when containing a larger proportion. 

 in the reducing flame. 

 The yellow color of the glass changes to a brown when warm and a chrome-green on cooling. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. 

 in the reducing flame. 

 As with borax. 

 * * * * *

32. Oxide of Chromium, Cr^{2}O^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Affords an intense color, but dissolves slowly. A small proportion colors the glass yellow when warm, and yellowish green when cold; a larger addition produces a dark red color when warm, which, on cooling, becomes yellow and finally a brilliant green with a tinge of yellow. 

 in the reducing flame. 

 A small quantity of the oxide renders the glass beautifully green both when warm and when cold. A larger addition changes it to a darker emerald green. Tin produces no change in the color. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear glass which has a pink tinge while warm, but on cooling becomes dusky green, and finally brilliantly green. 

 in the reducing flame. 

 As in the oxidizing flame, except that the colors are somewhat darker. Tin produces no further change. 

 * * * * *

33. Arsenious Acid, AsO^{3}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 No reaction. 

 in the reducing flame. 

 No reaction. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 No reaction. 

 in the reducing flame. 

 No reaction. 

 * * * * *

34. Tellurous Acid, TeO^{2}. 

 Behavior with Borax on Platinum wire

 in the oxidizing flame. 

 Dissolves to a clear colorless glass which, when treated on charcoal, becomes grey and dull from particles of reduced tellurium. 

 in the reducing flame. 

 As in the oxidizing flame. 

 Behavior with Mic. Salt on Platinum wire

 in the oxidizing flame. 

 As with borax. 

 in the reducing flame. 

 As with borax. 

 * * * * *

7. EXAMINATIONS WITH CARBONATE OF SODA. 

The carbonate of soda is pulverized and then kneaded to a paste withwater; the substance to be examined, in fine powder, is also mixedwith it. A small portion of this paste is placed on the charcoal, andgradually heated until the moisture is expelled, when the heat isbrought to the fusion of the bead, or as high as it can be raised. Several phenomena will take place, which must be closely observed. Notice whether the substance fuses with the bead, and if so, whetherthere is intumescence or not. Or, whether the substance undergoesreduction; or, whether neither of these reactions takes place, and, onthe contrary, the soda sinks into the charcoal, leaving the substanceintact upon its surface. If intumescence takes place, the presence ofeither tartaric acid, molybdic acid, silicic, or tungstic acid, isindicated. The silicic acid will fuse into a bead, which becomes clearwhen it is cold. Titanic acid will fuse into the bead, but may beeasily distinguished from the silicic acid by the bead remainingopaque when cold. 

Strontia and baryta will flow into the charcoal, but lime will not. The molybdic and tungstic acids combine with the soda, forming therespective salts. These salts are absorbed by the charcoal. If toogreat a quantity of soda is used, the bead will be quite likely tobecome opaque upon cooling, while, if too small a quantity of soda isused, a portion of the substance will remain undissolved. These can beequally avoided by either the addition of soda, or the substanceexperimented upon, as may be required. 

As silica and titanic acid are the only two substances that produce aclear bead, the student, if he gets a clear bead, may almost concludethat he is experimenting with silica, titanic acid being a raresubstance. When soda is heated with silica, a slight effervescencewill be the first phenomenon noticed. This is the escape of thecarbonic acid of the carbonate of soda, while the silicic acid takesits place, forming a glass with the soda. As titanic acid will notact in the same manner as silica, it can be easily distinguished byits bead not being perfectly pellucid. If the bead with which silicais fused should be tinted of a hyacinth or yellow color, this may beattributed to the presence of a small quantity of sulphur or asulphate, and this sometimes happens from the fact of the fluxcontaining sulphate of soda. The following metals, when exposed withcarbonate of soda to the reducing flame, are wholly or partiallyreduced, viz. The oxides of all the noble metals, the oxides and acidsof tungsten, molybdenum, arsenic, antimony, mercury, copper, tellurium, zinc, lead, bismuth, tin, cadmium, iron, nickel, andcobalt. Mercury and arsenic, as soon as they are reduced, aredissipated, while tellurium, bismuth, lead, antimony, cadmium, andzinc, are only partially volatilized, and, therefore, form sublimateson the charcoal. Those metals which are difficult of reduction shouldbe fused with oxalate of potassa, instead of the carbonate of soda. The carbonic oxide formed from the combustion of the acid of this saltis very efficient in the reduction of these metals. Carbonate of sodais very efficient for the detection of minute quantities of manganese. The mixture of the carbonate of soda with a small addition of nitrateof potassa, and the mineral containing manganese, must be fused onplatinum foil. The fused mass, when cooled, presents a fine bluecolor. 

 * * * * *

1. The following minerals, according to Griffin, produce beads withsoda, but do not fuse when heated alone: quartz, agalmatolyte, dioptase, hisingerite, sideroschilosite, leucite, rutile, pyrophyllite, wolckonskoite. 

2. The following minerals produce only slags with soda: allophane, cymophane, polymignite, æschynite, oerstedtite, titaniferous iron, tantalite, oxides of iron, yttro-tantalite, oxides of manganese, peroxide of tin (is reduced), hydrate of alumina, hydrate of magnesia, spinel, gahnite, worthite, carbonate of zinc, pechuran, zircon, thorite, andalusite, staurolite, gehlenite, chlorite spar, chromeochre, uwarowite, chromate of iron, carbonates of the earths, carbonates of the metallic oxides, basic phosphate of yttria, do. Ofalumina, do. Of lime, persulphate of iron, sulphate of alumina, aluminite, alumstone, fluoride of cerium, yttrocerite, topaz, corundum, pleonaste, chondrodite. 

3. The following minerals produce beads with a small quantity of soda, but produce slags if too much soda is added: phenakite, pierosmine, olivine, cerite, cyanite, talc, gadolinite, lithium-tourmaline. 

 * * * * *

1. The following minerals, when fused alone, produce beads. Of theseminerals the following produce beads with soda: the zeolites, spodumene, soda-spodumene, labrador, scapolite, sodalite (Greenland), elæolite, mica from primitive lime-stone, black talc, acmite, krokidolite, lievrite, cronstedtite, garnet, cerine, helvine, gadolinite, boracic acid, hydroboracite, tincal, boracite, datholite, botryolite, axinite, lapis lazuli, eudialyte, pyrosmalite, cryolite. 

2. The following minerals produce beads with a small quantity of soda, but if too much is added they produce slags: okenite, pectolite, redsilicate of manganese, black hydro-silicate of manganese, idocrase, manganesian garnets, orthite, pyrorthite, sordawalite, sodalite, fluorspar. 

3. The following minerals produce a slag with soda: brevicite, amphodelite, chlorite, fahlunite, pyrope, soap-stone (Cornish) reddichroite, pyrargillite, black potash tourmaline, wolfram, pharmacolite, scorodite, arseniate of iron, tetraphyline, hetepozite, uranite, phosphate of iron, do. Of strontia, do. Of magnesia, polyhalite, hauyne. 

4. The following metals are reduced by soda: tungstate of lead, molybdate of lead, vanadate of lead, chromate of lead, vauquelinite, cobalt bloom, nickel ochre, phosphate of copper, sulphate of lead, chloride of lead, and chloride of silver. 

 * * * * *

The following minerals fuse on the edges alone, when heated in theblowpipe flame:

1. The following produce beads with soda: steatite, meerschaum, felspar, albite, petalite, nepheline, anorthite, emerald, euclase, turquois, sodalite (Vesuvius). 

2. The following minerals produce beads with a small quantity ofsoda, but with the addition of more produce slags: tabular spar, diallage, hypersthene, epidote, zoisite. 

3. The following minerals produce slags only with soda:stilpnosiderite, plombgomme, serpentine, silicate of manganese (fromPiedmont), mica from granite, pimelite, pinite, blue dichroite, sphenc, karpholite, pyrochlore, tungstate of lime, green sodatourmaline, lazulite, heavy spar, gypsum. 

 * * * * *

The reactions of substances, when fused with soda in the flame ofoxidation may be of use to the student. A few of them are thereforegiven. Silica gives a clear glass. 

The oxide of tellurium and telluric acid gives a clear bead when it ishot, but white after it is cooled. 

Titanic acid gives a yellow bead when hot. 

The oxide of chromium gives also a clear yellow glass when hot, but isopaque when cold. 

Molybdic acid gives a clear bead when hot, but is turbid and whiteafter cooling. 

The oxides and acids of antimony give a clear and colorless bead whilehot, and white after cooling. 

Vanadic acid is absorbed by the charcoal, although it is not reduced. 

Tungstic acid gives a dark yellow clear bead while hot, but is opaqueand yellow when cold. 

The oxides of manganese give to the soda bead a fine characteristicgreen color. This is the case with a very small quantity. Thisreaction is best exhibited on platinum foil. 

Oxide of cobalt gives to the bead while hot a red color, which, uponbeing cooled, becomes grey. 

The oxide of copper gives a clear green bead while hot. 

The oxide of lead gives a clear colorless bead while hot, whichbecomes, upon cooling, of a dirty yellow color and opaque. 

 * * * * *

The following metals, when they are fused with soda on charcoal, inthe flame of reduction, produce volatile oxides, and leave anincrustation around the assay, viz. Bismuth, zinc, lead, cadmium, antimony, selenium, tellurium, and arsenic. 

_Bismuth_, under the reduction flame, yields small particles of metal, which are brittle and easily crushed. The incrustation is of a fleshcolor, or orange, when hot, but gets lighter as it cools. Thesublimate may be driven about the charcoal from place to place, byeither flame, but is finally dissipated. While antimony and tellurium, in the act of dissipation, give color to the flame, bismuth does not, and may thus be distinguished from them. 

_Zinc_ deposits an incrustation about the assay, which is yellow whilehot, but fades to white when cold. The reduction flame dissipates thisdeposit, but not that of oxidation. All the zinc minerals deposit theoxide incrustation about the assay, which, when moistened with asolution of cobalt and heated, changes to green. 

_Lead_ is very easily reduced, in small particles, and may be easilydistinguished by its flattening under the hammer, unlike bismuth. Itleaves an incrustation around the assay resembling that of bismuth, inthe color of it, and in the peculiar manner in which it lies aroundthe assay. 

_Cadmium_ deposits a dull reddish incrustation around the assay. Either of the flames dissipate the sublimate with the greatestreadiness. 

_Antimony_ reduces with readiness. At the same time it yieldsconsiderable vapor, and deposits an incrustation around the assay. This deposit can be driven about on the charcoal by either of theflames. The flame of reduction, however, produces the light blue colorof the antimony. 

_Selenium_ is deposited on the charcoal as a grey metallic-lookingsublimate, but sometimes appearing purple or blue. If the reductionflame is directed on this deposit, it is dissipated with a blue light. 

_Tellurium_ is deposited on the charcoal as a white sublimate, sometimes changing at the margin to an orange or red color. Theoxidation flame drives the deposit over the charcoal, while thereduction-flame dissipates it with a greenish color. 

_Arsenic_ is vaporized rapidly, while there is deposited around theassay a white incrustation of arsenious acid. This deposit will extendto some distance from the assay, and is readily volatilized, thereducing flame producing the characteristic alliaceous color. 

 * * * * *

The following metals, or their compounds, are reduced when fused withsoda on charcoal, in the flame of reduction. They are reduced tometallic particles, but give no incrustation, viz. Nickel, cobalt, iron, tin, copper, gold, silver, platinum, tungsten, and molybdenum. 

The particles of iron, nickel, and cobalt, it should be borne in mind, are attracted by the magnet. 

The following substances are neither fused nor reduced in soda, viz. Alumina, magnesia, lime, baryta, strontia, the oxide of uranium, theoxides of cerium, zirconia, tantalic acid, thorina, glucina, andyttria. Neither are the alkalies, as they sink into the charcoal. Thecarbonates of the earths, strontia, and baryta fuse. 

 * * * * *

Part III

SPECIAL REACTIONS; OR, THE BEHAVIOR OF SUBSTANCES BEFORE THE BLOWPIPE. 

Analytical chemistry may be termed the art of converting the unknownconstituents of substances, by means of certain operations, into newcombinations which we recognize through the physical and chemicalproperties which they manifest. 

It is, therefore, indispensably necessary, not only to be cognizant ofthe peculiar conditions by which these operations can be effected, butit is absolutely necessary to be acquainted with the forms andcombinations of the resulting product, and with every modificationwhich may be produced by altering the conditions of the analysis. 

We shall first give the behavior of simple substances before theblowpipe; and the student should study this part thoroughly, byrepeating each reaction, so that he can acquire a knowledge of thecolor, form, and physical properties in general, of the resultingcombination. There is nothing, perhaps, which will contribute morereadily to the progress of the pupil, than thorough practice with thereactions recommended in this part of the work, for when once thestudent shall have acquired a practical eye in the discernment of thepeculiar appearances of substances after they have undergone thedecompositions produced by the strong heat of the blowpipe flame, together with the reactions incident to these changes, then he willhave greatly progressed in his study, and the rest will becomparatively simple. 

A. METALLIC OXIDES. 

GROUP FIRST. --THE ALKALIES: POTASSA, SODA, AMMONIA, AND LITHIA. 

The alkalies, in their pure, or carbonated state, render reddenedlitmus paper blue. This is likewise the case with the sulphides of thealkalies. The neutral salts of the alkalies, formed with the strongacids, do not change litmus paper, but the salts formed with the weakacids, render the red litmus paper blue; for instance, the alkalinesalts with boracic acid. Fused with borax, soda, or microcosmic salt, they give a clear bead. The alkalies and their salts melt at a low redheat. The alkalies cannot be reduced to the metallic state before theblowpipe. They are not volatile when red hot, except the alkaliammonia, but they are volatile at a white heat. 

(_a. _) _Potassa. _(KO). --It is not found free, but in combination withinorganic and organic acids, as well in the animal as in the vegetableorganism, as in the mineral kingdom. In the pure, or anhydrous state, or as the carbonate, potassa absorbs moisture, and becomes fluid, oris deliquescent, as it is termed. By exposing potassa, or its easilyfusible salts (except the phosphate or borate), upon platinum wire, tothe point of the blue flame, there is communicated to the externalflame a violet color, in consequence of a reduction and reoxidation. This color, though characteristic of all the potassa compounds, isscarcely visible with the phosphate or borate salts of that alkali. The admixture of a very little soda (1/300th) destroys the colorimparted by the potassa, while the flame assumes a yellow color, characteristic of the soda. The presence of lithia changes the violetcolor of the potash into red. The silicates of potassa must exist inpretty large proportion before they can be detected by the violetcolor of the flame, and those minerals must melt easily at the edges. The presence of a little soda in these instances conceals the reactionin the potassa entirely. 

If alcohol is poured over potassa compounds which are powdered, andthen set on fire, the external flame appears violet-colored, particularly when stirred with a glass rod, and when the alcohol isreally consumed. The presence of soda in lithia will, in this caselikewise, hide by their own characteristic color, that of the potassa. 

The salts of potassa are absorbed when fused upon charcoal. Thesulphur, bromine, chlorine, and iodine compounds of potassa give awhite, but easily volatile sublimate upon the charcoal, around theplace where the fused substance reposed. This white sublimatemanifests itself only when the substance is melted and absorbed withinthe charcoal, and ceases to be visible as soon as it is submitted tothe reducing flame, while the external flame is colored violet;sulphate of potassa, for instance, is reduced by the glowing charcoalinto the sulphide. This latter is somewhat volatile, but by passingthrough the oxidation flame, it is again oxidized into the sulphate. This, being less volatile, sublimes upon the charcoal, but by exposingit again to the flame of reduction, it is reduced and carried off tobe again oxidized by its passage through the oxidation flame. 

Potassa and its compounds give, with soda, borax or microcosmic salt, as well when hot as cold, colorless beads, unless the acid associatedwith the alkali should itself produce a color. When borax is fusedwith some pure boracic acid, and sufficient of the oxide of nickel isadded, so that the beads appear of a brown color after being cooled, and then the bead thus produced fused with the substance suspected tocontain potassa, in the oxidation flame, the brown color is changed toblue. The presence of the other alkalies does not prevent thisreaction. As it is not possible to detect potassa compounds withunerring certainty by the blowpipe flame, the the wet method shouldbe resorted to for the purpose of confirming it. 

The _silicates of potassa_ must be prepared as follows, for analyticalpurposes by the wet way. Mix one part of the finely powdered substancewith two parts of soda (free from potassa), and one part of borax. Fuse the mixture upon charcoal in the oxidation flame to a clear, transparent bead. This is to be exposed again with the pincers to theoxidation flame, to burn off the adhering coal particles. Thenpulverize and dissolve in hydrochloric acid to separate the silica;evaporate to dryness, dissolve the residue in water, with theadmixture of a little alcohol, and test the filtrate with chloride ofplatinum for potassa. 

(_b. _) _Soda_ (NaO). --This is one of the most abundant substances, although seldom found free, but combined with chlorine or some otherless abundant compound. Soda, its hydrate and salts manifest ingeneral the same properties as their respective potash compounds; butthe salts of soda mostly contain crystal water, which leaves the saltsif they are exposed to the air, and the salts effervesce. 

By exposing soda or its compounds upon a platinum wire to the blueflame, a reddish-yellow color is communicated to the external flame, which appears as a long brilliant stream and considerably increased involume. The presence of potash does not prevent this reaction of soda. If there is too large a quantity of potash, the flame near to thesubstance is violet-colored, but the edge of the flame exhibits thecharacteristic tint of the soda. The presence of lithia changes theyellow color to a shade of red. 

When alcohol is poured over powdered soda compounds and lighted, theflame exhibits a reddish-yellow color, particularly if the alcohol isstirred up with a glass rod, or if the alcohol is nearly consumed. 

Fused upon charcoal, soda compounds are absorbed by the coal. Thesulphide, chloride, iodide, and bromide of soda yield a whitesublimate around the spot where the substance is laid, but thissublimate is not so copious as that of the potash compounds, anddisappears when touched with the reduction flame, communicating ayellow color to the external flame. The presence of soda in compoundsmust likewise be confined by reactions in the wet way. 

(_c. _) _Ammonia_ (NH^{4}O). --In the fused state, and at the usualtemperature, ammonia is a pungent gas, and exerts a reaction uponlitmus paper similar to potash and soda. Ammonium is considered bychemists as a metal, from the nature of its behavior with othersubstances. It has not been isolated, but its existence is nowgenerally conceded by all chemists. The ammonia salts are volatile, and many of them sublimate without being decomposed. 

The salts of ammonia, on being heated in the point of the blue flame, produce a feeble green color in the external flame, just previous totheir being converted into vapor. But this color is scarcely visible, and presents nothing characteristic. When the ammonia salts are mixedwith the carbonate of soda, and heated in a glass tube closed at oneend, carbonate of ammonia is sublimed, which can be readily recognizedby its penetrating smell of spirits of hartshorn. 

This sublimate will render blue a slip of red litmus paper. This canbe easily done by moistening the litmus paper, and then inserting theend of it in the tube. By holding a glass rod, moistened with dilutehydrochloric acid, over the mouth of the tube, a white vapor isinstantly rendered visible (sal ammoniac). 

(_d. _) _Lithia_ (LiO). --In the pure state, lithia is white andcrystalline, not easily soluble in water, and does not absorbmoisture. It changes red litmus to blue, and at a low red heat itmelts. Lithia or its salts, exposed to the point of the blue flame, communicates a red color to the external or oxidation flame, inconsequence of a reduction, sublimation, and re-oxidation of thelithia. An admixture of potash communicates to this flame areddish-violet color, and the presence of soda that of a yellowish-redor orange. If the soda, however, is in too great proportion, then itsintense yellow hides the red of the lithia. In the latter case thesubstance under test must be only imperfectly fused in the oxidationflame, and then dipped in wax or tallow. By exposing it now to thereduction flame, the red color imparted to the external flame by thelithia becomes visible, even if a considerable quantity of soda bepresent. A particular phenomenon appears with the phosphate of lithia, viz. , the phosphoric acid itself possesses the property ofcommunicating to the flame a bluish-green color. By its combinationwith lithia it still exhibits its characteristic color, while thelatter presents likewise its peculiar tint. Then we perceive a greenflame in the centre of the flame, while the red color of lithiasurrounds it. 

The _silicates_, which contain only a little lithia, produce only aslight hue in the flame, and often none at all. We have to mix onepart of the silicate with two parts of a mixture composed of one partof fluorspar and one and a half parts of bisulphate of potassa. Moisten the mass with water so that the mass will adhere, and thenmelt it upon a platinum wire in the reduction flame, when that ofoxidation will present the red color of lithia. 

The _Borates of lithia_ produce at first a green color, but it soonyields to the red of lithia. When alcohol is poured over lithia or itscompounds, and inflamed, it burns with a deep red color, particularlyif the fluid is stirred up with a glass rod, or when the alcohol isnearly consumed. This color presents the same modifications as thecorresponding ones communicated to the blowpipe as mentioned above. 

The salts of lithia are absorbed by charcoal when fused upon it. Thesulphide, bromide, iodide, and chloride of lithia produce upon thecharcoal a greyish-white sublimate, although not so copiously as thecorresponding compounds of potash and soda. This sublimate disappearswhen touched by the reduction flame, while the oxidation flame givesthe characteristic color of lithia. 

SECOND GROUP. --THE ALKALINE EARTHS, BARYTA, STRONTIA, LIME, ANDMAGNESIA. 

In the pure state, the alkaline earths are caustic, cause red litmuspaper to become blue, and are more or less soluble in water. Theirsulphides are also soluble. The carbonates and phosphates of thealkaline earths are insoluble in water. By igniting the carbonates, their carbonic acid is expelled, and the alkaline earths are left inthe caustic state. The alkaline earths are not volatile, and theirorganic salts are converted, by ignition, into carbonates. 

(_a. _) _Baryta. _ (BaO). --This alkaline earth does not occur free innature, but combined with acids, particularly with carbonic andsulphuric acids. In the pure state, baryta is of a greyish-whitecolor, presents an earthy appearance, and is easily powdered. Whensparingly moistened with water, it slakes, becomes heated, and forms adry, white powder. With still more water it forms a crystalline mass, the hydrate of baryta, which is completely soluble in hot water. Purebaryta is infusible; the hydrate fuses at a red heat, without the lossof its hydratic water; if caustic baryta is exposed for too great alength of time to the flame, it absorbs water, originated by thecombustion, and becomes a hydrate, when it will melt. Salts of baryta, formed with most acids, are insoluble in water; for instance, thesalts with sulphuric, carbonic, arsenic, phosphoric, and boracicacids. The salts of baryta, soluble in water, are decomposed byignition, except the chloride. 

Carbonate of baryta loses its carbonic acid at a red heat, becomescaustic, and colors red litmus paper blue. 

By exposing baryta or its compounds upon a platinum wire, or asplinter of the substance held with the platinum tongs, to the pointof the blue flame, a pale apple-green color is communicated to theexternal flame. This color appears at first very pale, but soonbecomes more intense. This color is most visible if the substance isoperated with in small quantities. The chloride of barium produces thedeepest color. This color is less intense if the carbonate or sulphateis used. The presence of strontia, lime, or magnesia, does notsuppress the reaction of the baryta, unless they greatly predominate. 

When alcohol is poured over baryta or its salts, and inflamed, afeeble green color is communicated to the flame, but this color shouldnot be considered a characteristic of the salt. 

Baryta and its compounds give, when fused with carbonate of soda uponplatinum foil, a clear bead. Fused with soda upon charcoal, it isabsorbed. The sulphate fuses at first to a clear bead, which soonspreads, and is absorbed and converted while boiling into a hepaticmass. If this mass is taken out, placed upon a piece of polishedsilver and moistened with a little water, a black spot of sulphide ofsilver is left after washing off the mass with water. 

Borax dissolves baryta and its compounds with a hissing noise, as wellin the flame of oxidation as in that of reduction. There is formed aclear bead which, with a certain degree of saturation, is clear whencold, but appears milk-white when overcharged, and of an opal, enamelappearance, when heated intermittingly, or with a vacillating flame, that changes frequently from the oxidating to the reducing flame. Baryta and its compounds produce the same reactions with microcosmicsalt. 

Baryta and its compounds fuse when exposed to ignition in theoxidizing flame. Moistened with the solution of nitrate of cobalt, andheated in the oxidation flame, it presents a bead, colored frombrick-red to brown, according to the quantity used. This colordisappears when cold, and the bead falls to a pale grey powder afterbeing exposed awhile to the air. When heated again, the color does notappear until fusion is effected. If carbonate of soda is fused uponplatinum wire with so much of the sesquioxide of manganese that agreen bead is produced, this bead, when fused with a sufficientquantity of baryta, or its compounds, after cooling, will appear of abluish-green, or light blue color. 

(_b. _) _Strontia_ (SrO). --Strontia and its compounds are analogous tothe respective ones of baryta. The hydrate of strontia has the sameproperties as the hydrate of baryta, except that it is less soluble inwater. The carbonate of strontia fuses a little at a red heat, swells, and bubbles up like cauliflower. This produces, in the blowpipe flame, an intense and splendid light, and now produces an alkaline reactionupon red litmus paper. The sulphate of strontia melts in the oxidationflame upon platinum foil, or upon charcoal, to a milk-white globule. This fuses upon charcoal, spreads and is reduced to the sulphide, which is absorbed by the charcoal. It now produces the same reactionsupon polished silver as the sulphate of baryta under the sameconditions. By exposing strontia and its compounds upon platinum wire, or as a splinter with the platinum tongs, to the point of the blueflame, the external flame appears of an intense crimson color. Thedeepest red color is produced by the chloride of strontium, particularly at the first moment of applying the heat. After the saltis fused, the red color ceases to be visible in the flame, by which itis distinguished from the chloride of lithium. The carbonate ofstrontia swells up and produces a splendid white light, while theexternal flame is colored of a fine purple-red. The color produced bythe sulphate of strontia is less intense. The presence of barytadestroys the reaction of the strontia, the flame presenting the lightgreen color of the baryta. 

If alcohol is poured over powdered strontia and inflamed, the flameappears purple or deep crimson, particularly if the fluid is stirredwith a glass rod, and when the alcohol is nearly consumed. 

The insoluble salts of strontia do not produce a very intense color. Baryta does not prevent the reaction of the soluble salts of strontia, unless it exists greatly in excess. In the presence of baryta, strontia can be detected by the following process: mix some of thesubstance under examination with some pure graphite and water, bygrinding in an agate mortar. Place the mixture upon charcoal, andexpose it for a while to the reduction flame. The substance becomesreduced to sulphide of barium and sulphide of strontium, when itshould be dissolved in hydrochloric acid. The solution should beevaporated to dryness, redissolved in a little water, and enoughalcohol added that a spirit of 80 per cent. Is produced. Inflame thespirit, and if strontia is present, the flame is tinged of a redcolor. This color can be discerned more distinctly by moistening somecotton with this spirit and inflaming it. 

If strontia or its compounds are fused with a green bead of carbonateof soda and sesquioxide of manganese, as described under the head ofbaryta, a bead of a brown, brownish-green, or dark grey color isproduced. Carbonate of soda does not dissolve pure strontia. Thecarbonate and sulphate of strontia melt with soda upon platinum foilto a bead, which is milk-white when cold, but fused upon charcoal theyare absorbed. Strontia or its compounds produce with borax, ormicrocosmic salt, the same reactions as baryta. When they aremoistened with nitrate of cobalt, and ignited in the oxidizing flame, a black, or grey infusible mass is produced. 

(_c. _) _Lime, Oxide of Calcium _(CaO). --Lime does not occur free innature, but in combination with acids, chiefly the carbonic andsulphuric. The phosphate occurs principally in bones. The hydrate andthe salts of lime are in their properties similar to those of the twopreceding alkaline earths. In the pure state, the oxide of calcium iswhite; it slakes, produces a high temperature, and falls into a whitepowder when sprinkled with a little water. It is now a hydrate, andhas greatly increased in volume. The hydrate of lime is far lesssoluble in water than either those of baryta or strontia, and is lesssoluble in hot water than in cold. Lime, its hydrate and sulphide ofcalcium, have a strong alkaline reaction upon red litmus paper. Limeand its hydrate are infusible, but produce at a strong red heat a veryintense and splendid white light, while the hydrate loses its water. The carbonate of lime is also infusible, but at a red heat thecarbonic acid is expelled, and the residue becomes caustic, appearswhiter, and produces an intenser light. The sulphate of lime meltswith difficulty, and presents the appearance of an enamelled mass whencold. By heating it upon charcoal it fuses in the reducing flame, andis reduced to a sulphide. This has a strong hepatic odor, and exertsan alkaline reaction upon red litmus paper. By exposing lime, or itscompounds, upon platinum wire--or as a small splinter of the mineralin the platinum tongs--to the point of the blue flame, a purple color, similar to that of lithia and strontia, is communicated to theexternal flame, but this color is not so intense as that produced bystrontia, and appears mixed with a slight tinge of yellow. This coloris most intense with the chloride of calcium, while the carbonate oflime produces at first a yellowish color, which becomes red, after theexpulsion of the carbonic acid. Sulphate of lime produces the samecolor, but not so intense. Among the silicates of lime only thetablespar (3CaO, 2SiO^{3}) produces a red color. Fluorspar (CaFl)produces a red as intense as pure lime, and fuses into a bead. Phosphate and borate of lime produce a green flame which is onlycharacteristic of their acids. The presence of baryta communicates agreen color to the flame. The presence of soda produces only a yellowcolor in the external flame. 

If alcohol is poured over lime or its compounds and inflamed, a redcolor is communicated to the flame. The presence of baryta or sodaprevents this reaction. Lime and its compounds do not dissolve much byfusion with carbonate of soda. If this fusion is effected on charcoal, the carbonate of soda is absorbed and the lime remains as ahalf-globular infusible mass on the charcoal. This is whatdistinguishes lime from baryta and strontia, and is a good method ofseparating the former from the latter. Lime and its compounds fusewith borax in the oxidizing and reducing flames to a clear bead, whichremains clear when cold, but when overcharged with an excess or heatedintermittingly, the bead appears, when cold, crystalline and uneven, and is not so milk-white as the bead of baryta or strontia, producedunder the same circumstances. The carbonate of lime is dissolved witha peculiar hissing noise. Microcosmic salt dissolves a large quantityof lime into a clear bead, which is milky when cold. When the bead hasbeen overcharged with lime, by a less excess, or by an intermittentflame, we will perceive in the bead, when cold, fine crystals in theform of needles. Lime and its compounds form by ignition with nitrateof cobalt, a black or greyish-black infusible mass. 

(_d. _) _Magnesia_ (MgO). --Magnesia occurs in nature in severalminerals. It exists in considerable quantity combined with carbonic, sulphuric, phosphoric, and silicic acids, etc. Magnesia and itshydrate are white and very voluminous, scarcely soluble in hot or coldwater, and restores moistened red litmus paper to its original bluecolor. Magnesia and its hydrate are infusible, the latter losing itswater by ignition. The carbonate of magnesia is infusible, loses itscarbonic acid at a red heat, and shrinks a little. It now exerts uponred litmus paper an alkaline reaction. The sulphate of magnesia, at ared heat, loses its water and sulphuric acid, is entirely infusible, and gives now an alkaline reaction. The artificial Astrachanit (NaO, SO^{3} + MgO, SO^{3} + 4HO) fuses easily. When fused on charcoal, thegreater part of the sulphate of soda is absorbed, and there remains aninfusible mass. 

Magnesia and its compounds do not produce any color in the externalflame, when heated in the point of the blue flame. The most of themagnesia minerals yield some water when heated in a glass tube closedat one end. 

Magnesia, in the pure state, or as the hydrate, does not fuse withsoda. Some of its compounds are infusible likewise with soda, andswell up slightly, while others of them melt with soda to a slightlyopaque mass. Some few (such as the borate of magnesia) give a clearbead with soda, though it becomes slightly turbid by cooling whensaturated with magnesia, and crystallizes in large facets. 

Magnesia and its compounds give beads with borax and microcosmic saltsimilar to those of lime. By igniting magnesia or its compounds verystrongly in the oxidizing flame, moistening with nitrate of cobalt, and re-igniting in the oxidation flame, they present, after acontinued blowing, a pale flesh-color, which is more visible whencold. It is indispensable that the magnesia compounds should becompletely white and free of colored substances, or the color referredto cannot be discerned. In general the reactions of magnesia beforethe blowpipe are not sufficient, and it will be necessary to confirmits presence or absence by aid of reagents applied in the wet way. 

THIRD GROUP. --THE EARTHS, ALUMINA, GLUCINA, YTTRIA, THORINA, ANDZIRCONIA. 

The substances of this group are distinguished from the preceding bytheir insolubility in water, in their pure or hydrated state--thatthey have no alkaline reaction upon litmus paper, nor form salts withcarbonic acid. The earths are not volatile, and, in the pure state, are infusible. They cannot be reduced to the metallic state before theblowpipe. The organic salts are destroyed by ignition, while theearths are left in the pure state, mixed with charcoal, from theorganic acids. The most of their neutral salts are insoluble in water;the soluble neutral salts change blue litmus paper to red, and losetheir acids when ignited. 

(_a. _) _Alumina_ (Al^{2}O^{3}). --This earth is one of our most commonminerals. It occurs free in nature in many minerals, as sapphire, etc. ; or in combination with sulphuric acid, phosphoric acid, andfluorine, and chiefly silicates. Pure alumina is a white crystallinepowder, or yellowish-white, and amorphous when produced by drying thehydrate, separated chemically from its salts. Alumina is quiteunalterable in the fire; the hydrate, however, losing its water at alow red heat. The neutral salts of alumina, with most acids, areinsoluble in water. Those soluble in it have an acid reaction uponlitmus paper, changing the blue into red. 

The sulphates of alumina eliminate water when heated in a glass tubeclosed at one end. By ignition, sulphurous acid (SO^{2}) is given off, which can be recognized by its smell, and by its acid reaction uponblue litmus paper, when a small strip of it moistened is broughtwithin the orifice of the tube; an infusible residue is left in thetube. 

The greater part of the alumina compounds give off water with heat;the most of them are also infusible, except a few phosphates andsilicates. 

Pure alumina does not fuse with carbonate of soda. The sulphates, whenexposed upon charcoal with soda to the reducing flame, leave a hepaticresidue. The phosphates melt with a little soda, with a hissing noise, to a semi-transparent mass, but they are infusible with the additionof soda, and give only a tough mass. This is the case, likewise, withthe silicates of alumina. Fluoride of aluminium melts with carbonateof soda to a clear bead, spreads by cooling, and appears thenmilk-white. Borax dissolves the alumina compounds slowly in theoxidizing and reducing flames to a clear bead, which is also clearwhen cold, or heated intermittingly with a vacillating flame. The beadis turbid, as well in the heat as the cold, when an excess of aluminais present. When the alumina compound is added to excess in thepowdered form, the bead appears crystalline upon cooling, and meltsagain with great difficulty. 

Alumina and its compounds are slowly dissolved in the microcosmic saltto a bead, clear in both flames, and when hot or cold. When alumina isadded to excess, the undissolved portion appears semi-transparent. Alumina melts with bisulphate of potash into a mass soluble in water. When the powdered alumina compounds are strongly ignited in theoxidizing flame, then moistened with nitrate of cobalt, and re-ignitedin the oxidizing flame, an infusible mass is left, which appears, whencooled, of an intense blue color. The presence of colored metallicoxides, in considerable quantity, will alter or suppress thisreaction. The silicates of the alkalies produce, in a very strongheat, or continued heat, with nitrate of cobalt, a pale blue color. The blue color produced by alumina is only distinctly visible bydaylight; by candle-light it appears of a dirty violet color. 

(_b. _) _Glucina. _ (G^{2}O^{3}). --Glucina only occurs in a few rareminerals, in combination with silica and alumina. It is white andinsoluble in the pure state, and its properties generally are similarto those of alumina. The most of its compounds are infusible, andyield water by distillation. Carbonate of soda does not dissolveglucina by ignition. Silicate of glucina melts with carbonate of sodato a colorless globule. Borax and microcosmic salt dissolve glucinaand its compounds to a colorless bead which, when overcharged withglucina, or heated with the intermittent flame appears, after cooling, turbid or milk-white. Glucina yields, by ignition with nitrate ofcobalt, a black, or dark grey infusible mass. 

(_c. _) _Yttria_ (YO) occurs only in a few rare minerals, and usuallyin company with terbium and erbium. Its reactions before the blowpipeare similar to the preceding, but for its detection in compounds itwill be necessary to resort to analysis in the wet way. 

(_d. _) _Zirconia_ (Zr^{2}O^{3}). --This substance resembles alumina inappearance, though it occurs only in a few rare minerals. It is in thepure state infusible, and at a red heat produces such a splendid andvivid white light that the eyes can scarcely endure it. Its otherreactions before the blowpipe are analogous to glucina. Microcosmicsalt does not dissolve so much zirconia as glucina, and is more proneto give a turbid bead. Zirconia yields with nitrate of cobalt, whenignited, an infusible black mass. To recognize zirconia in compoundswe must resort to fluid analysis. 

(_e. _) _Thorina_ (ThO). --This is the rarest among the rare minerals. In the pure state it is white and infusible, and will not melt withthe carbonate of soda. Borax dissolves thorina slowly to a colorless, transparent bead, which will remain so when heated with theintermittent flame. If overcharged with the thorina, the beadpresents, on cooling, a milky hue. Microcosmic salt dissolves thethorina very tardily. By ignition with nitrate of cobalt, thorina isconverted into an infusible black mass, CLASS II. 

FOURTH GROUP. CERIUM, LANTHANIUM, DIDYMIUM, COLUMBIUM, NIOBIUM, PELOPIUM, TITANIUM, URANIUM, VANADIUM, CHROMIUM, MANGANESE. 

The substances of this group cannot be reduced to the metallic state, neither by heating them _per se_, nor by fusing them with reagents. They give by fusion with borax or microcosmic salt, colored beads, while the preceding groups give colorless beads. 

(_a. _) _Cerium_ (Ce). --This metal occurs in the oxidated state in afew rare minerals, and is associated with lanthanium and didymium, combined with fluorine, phosphoric acid, carbonic acid, silica, etc. When reduced artificially, it forms a grey metallic powder. 

(_a. _) _Protoxide of Cerium_ (CeO). --It exists in the pure state asthe hydrate, and is of a white color. It soon oxidizes and becomesyellow, when placed in contact with the air. When heated in theoxidation flame, it is converted into the sesquioxide, and then ischanged into light brick-red color. In the oxidation flame it isdissolved by borax into a clear bead, which appears of an orange orred while hot, but becomes yellow upon cooling. When highly saturatedwith the metal, or when heated with a fluctuating flame, the beadappears enamelled as when cold. In the reduction flame it is dissolvedby borax to a clear yellow bead, which is colorless when cold. If toomuch of the metal exists in the bead, it then appears enamelled whencooled. 

Microcosmic salt dissolves it, in the oxidation flame, to a clearbead, which is colored dark yellow or orange, but loses its color whencold. In the reduction flame the bead is colorless when either hot orcold. Even if highly saturated with the metal, the bead remainscolorless when cold. By fusing it with carbonate of soda upon charcoalin the reduction flame, the soda is absorbed by the charcoal, whilethe protoxide of the metal remains as a light grey powder. 

(_B. _) _Sesquioxide of Cerium_ (Ce^{2}O^{3}). --This oxide, in the purestate, is a red powder. When heated with hydrochloric acid, itproduces chlorine gas, and is dissolved to a salt of the protoxide. Itis not affected by either the flame of oxidation or of reduction; whenfused with borax or microcosmic salt, it acts like the protoxide. Itdoes not fuse with soda upon charcoal. In the reduction flame it isreduced to the protoxide, which remains of a light grey color, whilethe soda is absorbed by the charcoal. 

(_b. _) _Lanthanium_ (La. )--This metal is invariably associated withcerium. It presents, in its metallic state, a dark grey powder, whichby compression acquires the metallic lustre. 

The _oxide of lanthanium_ (LaO) is white, and its salts are colorless. Heated upon charcoal, it does not change either in the oxidation flameor that of reduction. With borax, in the flame of oxidation orreduction, it gives a clear colorless bead. This bead, if saturated, and when hot, presents a yellow appearance, but is clouded orenamelled when cold. With microcosmic salt the same appearance isindicated. It does not fuse with carbonate of soda, but the soda isabsorbed by the charcoal, while the oxide remains of a grey color. 

(_c. _) _Didymium_ (D). --This metal occurs only in combination with thepreceding ones, and it is therefore, like them, a rare one. 

_Oxide of Didymium_ (DO). --This oxide is of a brown color, while itssalts present a reddish-violet or amethyst color. The oxide isinfusible in the oxidation flame, and in that of reduction it losesits brown color and changes to grey. With borax in the oxidationflame, it fuses to a clear dark red or violet bead, which retains itsclearness when highly saturated with the oxide, or if heated with afluctuating flame. 

The reactions with microcosmic salt are the same as with borax. 

It does not melt with carbonate of soda upon charcoal, but the oxideremains with a grey color, while the soda is absorbed by the charcoal. 

(_d. _) _Columbium, _ (_Tantalum_--Ta). --This rare metal occurs quitesparingly in the minerals _tantalite_, _yttrotantalite_, etc. , ascolumbic acid. In the metallic state, it presents the appearance of ablack powder, which, when compressed, exhibits the metallic lustre. When heated in the air it is oxidized into columbic acid, and is onlysoluble in hydrofluoric acid, yielding hydrogen. It is oxidized byfusion with carbonate of soda or potash. 

_Columbic Acid_ (Ta^{2}O^{3}) is a white powder, and is infusible. When heated in the flame of oxidation or reduction, it appears of alight yellow while hot, but becomes colorless when cold. With borax, in the flames of oxidation and reduction, it fuses to a clear bead, which appears by a certain degree of saturation, of a yellow color solong as it continues hot, but becomes colorless when cold. Ifovercharged, or heated with an intermittent flame, it presents anenamel white when cool. 

It melts with microcosmic salt quite readily in both of the flames, toa clear bead, which appears, if a considerable quantity of columbicacid be present, of a yellow color while hot, but colorless when cold, and does not become clouded if the intermittent flame be applied toit. 

With carbonate of soda it fuses with effervescence to a bead whichspreads over the charcoal. Melted with more soda, it becomes absorbedby the charcoal. 

It yields, moistened with a solution of nitrate of cobalt, and exposedto the oxidation flame after continued blowing, an infusible mass, presenting while hot a light grey color, but after being cooled thatof a light red, similar to the color presented by magnesia under thesame circumstances. But if there be some alkali mixed with it, afusion at the edges will be manifest, and it will yield by cooling abluish-black mass. 

(_e. _) _Niobium_ (Ni). --This metal occurs as niobic acid in columbite(tantalite). Niobic acid is in its properties similar to columbicacid. It is white and infusible. By heating it either in the flames ofreduction or oxidation, it presents as long as it continues hot, agreenish-yellow color, but becomes white when cool. Borax dissolves itin the oxidation flame quite readily to a clear bead, which, with aconsiderable quantity of niobic acid, is yellow when hot, buttransparent and colorless when cold. A saturated bead is clear wheneither hot or cold, but becomes opaque when heated intermittingly. 

In the flame of reduction, borax is capable of dissolving more of theniobic acid, so that a bead overcharged and opaque in the oxidationflame appears quite clear when heated in the flame of reduction. Abead overcharged in the flame of reduction, appears by cooling dim andbluish-grey. 

Microcosmic salt dissolves in the flame of oxidation a great quantityof it to a clear bead, which is yellow while hot, but colorless whencold. 

In the flame of reduction, and in presence of a considerable quantityof niobic acid, the bead appears while hot of a light dirty bluecolor, and when cold, of a violet hue; but by the addition of moreniobic acid, the bead, when hot, is of a dirty dark blue color, andwhen cold, of a transparent blue. In the presence of the oxides ofiron, the bead is, while hot, of a brownish-red color, but changingwhen cool to a dark yellow. 

This acid fuses with an equal quantity of carbonate of soda uponcharcoal, to a bead which spreads very quickly, and is then infusible. When fused with still more soda, it is absorbed. 

When moistened with nitrate of cobalt, and heated in the flame ofoxidation, it yields an infusible mass which appears grey when hot, and dirty green when cold; but if the heat has been too strong, it isfused a little at the edges, which present a dark bluish-grey color. 

_Pelopium_ (Pe). --This metal occurs as an acid in the mineralcolumbite (tantalite), and is very similar to the two precedingmetals. 

(_f. _) _Pelopic Acid_ (PeO^{3}). --This acid is white, and appearsyellow when heated, but resumes its white color when cold. Boraxdissolves it in the oxidation flame to a clear colorless bead, whichappears, when overcharged and heated intermittingly, enamel-white whencold. This is likewise the case in the flame of reduction, but whenovercharged the color is light grey, when the bead is cooled. 

Microcosmic salt dissolves it in the flame of oxidation, to a clearyellow bead, which loses its color when cold. In the reduction flame, when the bead is highly saturated, a violet-brown color is produced. In presence of the oxides of iron, the reactions are like those ofniobic acid. With carbonate of soda, the reactions are similar tothose of niobic acid. By heating with nitrate of cobalt, it yields alight grey infusible mass. 

(_g. _) _Titanium_ (Ti). --This metal occurs occasionally in the slagsof iron works, in the metallic state, as small cubical crystals of ared color. It is a very hard metal, and very infusible. Titanic acidoccurs in nature crystallized in _anatase_, _arkansite_, _brookite_, and _rutile_. Titanium is harder than agate, entirely infusible, andloses only a little of its lustre, which can be regained by fusionwith borax. It does not melt with carbonate of soda, borax, ormicrocosmic salt, and is insoluble in every acid except thehydrofluoric. By ignition with saltpetre it is converted into titanicacid, which combines with the potassium, forming the titanate ofpotassium. 

_Titanic Acid_ (TiO^{2}) is white, insoluble, and, when heated, itappears yellow while hot, but resumes upon cooling its white color. 

Borax dissolves it in the oxidation flame to a clear yellow bead, which when cool is colorless. When overcharged, or heated with theintermitting flame, it is enamel-white after being cooled. In thereduction flame, the bead appears yellow, if the acid exists in smallquantity, but if more be added, then it is of an orange, or darkyellow, or even brown. The saturated bead, when heated intermittingly, appears when cold of an enamelled blue. By addition of the acid, andby heating the bead on charcoal in the reduction flame, it becomesdark yellow while hot, but dark blue, or black and opaque when cold. This bead appears, when heated intermittingly, of a light blue, andwhen cold, enamelled. 

Microcosmic salt fuses with it in the oxidation flame to a clearcolorless bead, which appears yellow only in the presence of aquantity of titanic acid, though by cooling it loses its color. In thereduction flame this bead exhibits a yellow color when hot, but is redwhile cooling, and when cold of a beautiful bluish-violet. If the beadis overcharged, the color becomes so dark that the bead appearsopaque, though not presenting an enamel appearance. By heating thebead again in the oxidation flame the color disappears. The additionof some tin promotes the reduction. If the titanic acid contains oxideof iron, or if some is added, the bead appears, when cold, brownish-yellow, or brownish-red. 

By fusion with carbonate of soda, titanic acid is dissolved witheffervescence to a clear dark yellow bead, which crystallizes bycooling, whereby so much heat is eliminated, that the bead, at theinstant of its crystallization, glows with great brightness. Areduction to a metal cannot, however, be effected. By ignition with asolution of nitrate of cobalt in the oxidation flame, it yields aninfusible yellowish-green mass. 

(_h. _) _Uranium_ (U). --This rare metal occurs in the form of protoxidealong with other oxides, in the mineral _pitch-blende_; as peroxide in_uranite_ and _uran-mica_, associated with phosphoric acid and lime. 

In the metallic state it presents the appearance of a dark grey mass, which is infusible, and remains unchanged when under water, or whenexposed to dry air, but, when heated in the oxidation flame, itbecomes oxidized, with lively sparkling, to a dark green mass, composed of the protoxide and peroxide. 

The _protoxide of uranium_ (UO) is black, uncrystalline, or forms abrown powder. When exposed to heat it is converted partially intoperoxide, when it has a dark green color. 

The _peroxide of uranium_ (U^{2}O^{3}) is of an orange color, whileits hydrate is of a fine yellow color, and in the form of a powder. The salts are yellow. 

By heating it in the oxidation flame, it acquires a dark green color, and is partly reduced to protoxide. In the reduction flame it presentsa black appearance, and is there completely reduced to protoxide. 

Borax dissolves it in the oxidation flame to a clear dark yellow bead, which is colorless when cold, if the metal is not present in greatquantity. If more of the metal, or peroxide, be added, the beadchanges to orange when hot, and light yellow when cold. When heatedwith the intermittent flame, it requires a large quantity of theperoxide to produce an enamel appearance in the cooled bead. 

In the flame of reduction the bead becomes of a dirty green color, being partly reduced to protoxide, and appears, with a certain degreeof saturation, black, when heated intermittingly, but never enamelled. The bead appears on charcoal, and with the addition of tin, of a darkgreen color. 

It fuses with microcosmic salt in the oxidation flame to a clearyellow bead, which is greenish-yellow when cold. In the reductionflame it produces a beautiful green bead, which increases when cold. 

When fused upon charcoal with the addition of tin, its color isdarker. Carbonate of soda does not dissolve it, although with a verysmall portion of soda it gives indications of fusion, but with stillmore of the soda it forms a yellow, or light-brown mass, which isabsorbed by the charcoal, but it is not reduced to the metallic state. 

(_i. _) _Vanadium_ (V). --This very rare mineral is found in smallquantity in iron-ores, in Sweden, and as vanadic acid in a few rareminerals. The metal presents the appearance of an iron-grey powder, and sometimes that of a silver-white mass. It is not oxidized eitherby air or water, and is infusible. 

_Vanadic Acid_ (VO^{3}) fuses upon platinum foil to a deep orangeliquid, which becomes crystalline after cooling. When fused uponcharcoal, one part of it is absorbed, while the rest remains upon thecharcoal and is reduced to protoxide similar in appearance tographite. 

A small portion of it fuses with borax in the oxidation flame to aclear colorless bead, which appears, with the addition of more vanadicacid, of a yellow color, but changes to green when cold. 

In the reduction flame the bead is brown while hot, but changes, uponcooling, to a beautiful sapphire-green. At the moment ofcrystallization, and at a degree of heat by which at daylight noglowing of the heated mass is visible it begins to glow again. Theglow spreads from the periphery to the centre of the mass, and iscaused by the heat liberated by the sudden crystallization of themass. It now exhibits an orange color, and is composed of needlecrystals in a compact mass. 

Microcosmic salt and vanadic acid fuse in the oxidation flame to adark yellow bead which, upon cooling, loses much of its color. 

In the reduction flame the bead is brown while hot, but, upon cooling, acquires a beautiful green color. 

Vanadic acid fuses with carbonate of soda upon charcoal, and isabsorbed. 

(_k. _) _Chromium_ (Cr) occurs in the metallic state only in a verysmall quantity in meteoric iron, but is frequently found in union withoxygen, as oxide in chrome iron ore, and as chromic acid in some leadores. 

In the metallic state it is of a light grey color, with but littlemetallic lustre, very hard, and not very fusible. Acids do not actupon it, except the hydrofluoric; fused with nitre, it forms chromateof potassa. It is unaltered in the blowpipe flame. 

_Sesquioxide of Chromium_ (Cr^{2}O^{3}). --This oxide forms blackcrystals of great hardness, and is sometimes seen as a green powder. Its hydrate (Cr^{2}O^{3} + 6HO) is of a bluish-grey color. It formswith acids two classes of isomeric salts, some of which are of agreen color, and the others violet-red or amethyst. The neutral andsoluble salts have an acid reaction upon blue litmus paper, and aredecomposed by ignition. 

Sesquioxide of chromium in the oxidation and reduction flames isunchangable. When exposed to heat, the hydrate loses its water, andgives a peculiarly beautiful flame. In the oxidation flame boraxdissolves the sesquioxide of chromium slowly to a yellow bead (chromicacid) which is yellowish green when cold. Upon the addition of more ofthe oxide, the bead is dark red while hot, but changes to green as itbecomes cold. 

In the reduction flame the bead is of a beautiful green color, bothwhile hot and when cold. It is here distinguished from vanadic acid, which gives a brownish or yellow bead while hot. 

With microcosmic salt it fuses in the oxidation flame to a clearyellow bead, which appears, as it cools, of a dirty-green, color, butupon being cool is of a fine green color. If there be a superabundanceof the oxide, so that the microcosmic salt cannot dissolve it, thebead swells up, and is converted into a foamy mass, in consequence ofthe development of gases. 

In the reduction flame it fuses to a fine green bead. The addition ofa little tin renders the green still deeper. 

Sesquioxide of chromium fuses with carbonate of soda upon platinumfoil to a brown or yellow bead, which, upon cooling, appears of alighter color and transparent (chromate of sodium). 

When fused with soda upon charcoal, the soda is absorbed, and thegreen oxide is left upon it, but is never reduced to the metallicstate. 

_Chromic Acid_ (CrO^{3}) crystallizes in the form of deep ruby redneedles. It is decomposed into sesquioxide and oxygen when heated. This decomposition is attended with a very lively emission of light, but this is not the case if the chromic acid has been attained by thecoöperation of an aqueous solution, unless the reduction is effectedin the vapor of ammonia. Before the blowpipe chromic acid produces thesame reactions as the sesquioxide. 

(_l. _) _Manganese_ (Mn). --This metal occurs in considerable abundance, principally as oxides, less frequently as salts, and sometimes incombination with sulphur and arsenic. It is found in plants, andpasses with them into the animal body. In the metallic state, it isfound frequently in cast iron and steel. It is a hard, brittle metal, fusible with difficulty, and of a light grey color. It tarnishes uponexposure to the air and under water, and falls into a powder. 

_Protoxide of Manganese_ exists as a green powder; as hydrateseparated by caustic alkalies, it is white, but oxidizes very speedilyupon exposure to the air. The protoxide is the base of the salts ofmanganese. These salts, which are soluble in water, are decomposedwhen heated in the presence of the air--except the sulphate (MnO, SO^{3}), but if the latter is exposed to ignition for awhile, it thenceases to be soluble in water, or at least only sparingly so. 

_Sesquioxide of Manganese_ (Mn^{2}O^{3}) Occurs very sparingly innature as small black crystals (_Braunite_) which give, when ground, abrown powder. When prepared by chemical process, it is in the form ofa black powder. The hydrate occurs sometimes in nature as blackcrystals (_manganite_). By digestion with acids, it is dissolved intosalts of the protoxide. With hydrochloric acid, it yields chlorine. 

The _prot-sesquioxide of manganese_ (MnO + Mn^{2}O^{3}) occurssometimes in black _crystals_ (_hausmannite_). Prepared artificially, it is in the form of a brown powder. 

_Peroxide of Manganese_ (MnO^{2}) occurs in considerable abundance asa soft black amorphous mass, or crystallized as pyrolusite, alsoreniform and fibrous. It is deprived of a part of its oxygen whenexposed to ignition. It eliminates a considerable quantity of chlorinefrom hydrochloric acid, and is thereby converted into chloride ofmanganese (ClMn). 

Most of the manganese compounds which occur in nature yield water whenheated in a glass tube closed at one end. The sesquioxide and peroxidegive out oxygen when strongly heated, which can be readily detected bythe increased glow which it causes, if a piece of lighted wood orpaper is brought to the mouth of the tube. The residue left in thetube is a brown mass (MnO + Mn^{2}O^{3}). 

When exposed to ignition with free access of air, all manganese oxidesare converted into (MnO + Mn^{2}O^{3}), but without fusion. Such, atleast, is the statement of some of the German chemists, although itwill admit perhaps of further investigation. 

Manganese oxides fuse with borax in the oxidation flame to a clear andintensely colored bead, of a violet hue while hot, but changing to redas it cools. If a considerable quantity of the oxide is added, thebead acquires a color so dark as to become opaque. If such be thecase, we have to press it flat, by which its proper color will becomemanifest. 

In the reduction flame the bead is colorless. A very dark colored beadmust be fused upon charcoal with the addition of some tin. The beadmust be cooled very suddenly, for if it cools too slowly, it then hastime to oxidize again. This may be effected by pushing it off theplatinum wire, or the charcoal, and pressing it flat with the forceps. 

The oxides of manganese fuse with microcosmic salt in the oxidationflame, to a clear brownish-violet bead, which appears reddish-violetwhile cooling. This bead does not become opaque when overcharged withmanganese. As long as it is kept in fusion a continued boiling oreffervescence takes place, produced by the expulsion of oxygen, inconsequence of the fact that the microcosmic salt cannot dissolve muchsesquioxide, while the rest is reduced to protoxide, is re-oxidated, and instantly again reduced. If the manganese is present in such aminute quantity as not to perceptibly tinge the bead, the color may bemade to appear by the contact of a crystal of nitre while hot. Thebead foams up upon the addition of the nitre, and the foam appears, after cooling, of a rose-red or violet color. In the reduction flamethe bead sometimes becomes colorless. 

The oxides of manganese fuse with carbonate of soda upon platinumfoil or wire, to a clear green bead, which appears bluish-green andpartially opaque when cold (manganate of soda NaO + MnO^{3}). A veryminute trace of manganese will produce this green color. The oxides ofmanganese cannot be reduced upon charcoal with carbonate of sodabefore the blowpipe. The soda is absorbed, and (MnO + Mn^{2}O^{3}) isleft. 

GROUP FIFTH. --IRON, COBALT, NICKEL. 

The oxides of this group are reduced to the metallic state when fusedwith carbonate of soda upon charcoal in the reduction flame. Metalswhen thus reduced form powders, are not fusible or volatile in theblowpipe flame, but they are attracted by the magnet. 

Furthermore, these oxides are not dissolved by carbonate of soda inthe oxidation flame, but they produce colored beads with borax andmicrocosmic salt. 

(_a. _) _Iron. _--It occurs in great abundance in nature. It is found inseveral places in America in the metallic state, and it likewiseoccurs in the same state in meteors. It occurs chiefly as the oxide(red hematite, brown hematite, magnetic oxide, etc. ), and frequentlyin combination with sulphur. Iron also forms a constituent of theblood. 

Metallic iron is of a grey color, and presents the metallic lustrevividly when polished. It is very ductile, malleable, and tenacious. It is very hard at common temperatures, but soft and yielding at a redheat. 

In dry and cold air, iron does not oxidize, but when the air is dryand moist, it oxidizes rapidly. This likewise takes place with greatrapidity when the metal is heated to redness. When submitted to awhite heat iron burns with brilliant scintillations. 

_Protoxide of Iron_ (FeO). --This oxide does not occur pure in nature, but in union with the peroxide of iron and other substances. Itpresents the form of a black powder, and has some metallic lustre, isbrittle, and fuses at a high temperature to a vitreous looking mass. It is attracted by the magnet, and of course is susceptible ofbecoming magnetic itself. It forms with water a hydrate, but thispasses so rapidly into a state of higher oxidation, that it isdifficult to keep it in the pure state. 

_Magnetic Oxide of Iron_ (FeO + Fe^{2}O^{3}). --This peculiar oxide isof a dark color, and is magnetic, so that tacks or small nails adhereto it when brought in contact with it. It is the variety of the oxidetermed "loadstone. " It is found frequently crystallized in octahedronsin Scandinavia and other places. Magnetic oxide of iron is producedwhen red-hot iron is hammered. 

_Sesquioxide of Iron_ (Fe^{2}O^{3}). --This oxide is found native ingreat abundance as red hematite and specular iron, crystallized in therhombic form. In the crystalline state it is of a blackish-grey color, and possessed of the metallic lustre. When powdered, it forms abrownish-red mass. When artificially prepared, it presents theappearance of a blood-red powder. It is not magnetic, and has lessaffinity for acids than the protoxide. Its hydrate is found native asbrown hematite. 

By exposing the peroxide of iron to the oxidation flame, it is notacted upon, but in the reduction flame it becomes reduced to themagnetic oxide. 

The oxides of iron are dissolved by borax in the oxidation flame to aclear dark-yellow or dark-red bead, which appears lighter whilecooling, and yellowish when cold. In the presence of a very smallquantity of iron, the bead appears colorless when cold. If the iron isincreased, the bead is opaque while cooling, and of a dirtydark-yellow color when cold. In the reduction flame, and fused uponplatinum wire, the bead appears dark green (FeO + Fe^{2}O^{3}). By theaddition of some tin, and fused upon charcoal, the bead appearsbluish-green, or not unlike that of sulphate of iron. 

Microcosmic salt dissolves the oxides of iron in the oxidation flameto a clear bead, which, by the addition of a considerable quantity ofiron, becomes of an orange color while hot, but gets lighter whilecooling, presenting finally a greenish hue, and gradually becominglighter, till, when cold, it is colorless. If the iron is increased, the hot bead presents a dark red color, but while cooling abrownish-red, which changes to a dirty-green, and, when cold, to abrownish-red color. The decrease of the color during the transitionfrom the hot to the cold state is still greater in the bead formed bythe microcosmic salt. 

In the reduction flame no change is visible if the quantity of iron besmall. By the addition of more iron, the hot bead appears red, andwhile cooling, changes to yellow, then green, and, when cold, is of adull red. By fusing the bead on charcoal with a small addition of tin, it exhibits, while cooling, a bluish-green color, but, when cold, iscolorless. 

The oxides of iron are not dissolved in the oxidation flame by fusionwith carbonate of soda. By ignition with soda upon charcoal in thereduction flame, they are absorbed and reduced to the metallic state. Cut out this portion of the charcoal; grind it with the addition ofsome water in an agate mortar, for the purpose of washing off thecarbon particles, when the iron will remain as a grey magnetic powder. 

(_b. _) _Cobalt_ (Co) occurs in combination with arsenic and sulphur, and associated with nickel and iron. It is found occasionally incombination with selenium, and there are a traces of it in meteoriciron. In the metallic state it is of a light, reddish-grey color, rather brittle, and only fusible at a strong white heat; at commontemperatures it is unalterable by air or water. At a red heat, itoxidizes slowly and decomposes water; at a white heat it burns with ared flame. Cobalt is soluble in dilute sulphuric or hydrochloric acidby the aid of heat, whereby hydrogen is eliminated. These solutionshave a fine red color. 

_Protoxide of Cobalt_ (CoO). --It is an olive-green powder, but, byexposure to the air, it becomes gradually brown. Its hydrate is a richred powder. The solution of its salts is red, but the aqueous solutionis often blue. 

When heated in the oxidation flame, the protoxide is converted intothe black proto-sesquioxide (CoO + Co^{2}O^{3}). In the reductionflame it shrinks and is reduced without fusion to the metallic state. It is now attracted by the magnet and acquires lustre by compression. 

Borax dissolves it in the oxidation flame, and produces a clear, intensely colored blue bead, which remains transparent and of the samebeautiful blue when cold. This blue is likewise manifest even if thebead be heated intermittingly. If the cobalt exists in considerablequantity, the color of the bead is so intense as to appear almostblack. 

This reaction of cobalt is so characteristic and sensitive that it candetect a minute trace. 

With microcosmic salt the same reaction is exhibited, but not sosensitive, nor is the bead so intensely colored when cold as that withborax. 

By fusion with carbonate of soda upon a platinum wire, with a verysmall portion of cobalt, a bright red colored mass is produced whichappears grey, or slightly green when cold. By fusion upon platinumfoil the fused portion floats down from the sides, and the foil iscoated around the undissolved part, with a thin, dark-red sublimate. When fused upon charcoal, and in the reduction flame, it is reducedwith soda to a grey powder, which is attracted by the magnet, andexhibits the metallic lustre by compression. 

_Sesquioxide of Cobalt_ (Co^{2}O^{3}). --It is a dark brown powder. Itshydrate (2HO + Co^{2}O^{3}) is a brown powder. It is soluble only inacetic acid as the acetate of the sesquioxide. All other acidsdissolve its salts to protoxide, the hydrochloric acid producingchloric gas. By ignition in the oxidation flame, it is converted intothe proto-sesquioxide (CoO + Co^{2}O^{3}) and produces with reagentsbefore the blowpipe the same reactions as the protoxide. 

(_c. _) _Nickel_ (Ni). --This metal occurs invariably associated withcobalt, and in analogous combinations, chiefly as the arsenicalnickel. In the metallic state it is greyish, silver-white, has a highlustre, is hard, and malleable both cold and hot. At commontemperatures, it is unalterable either in dry or moist air. Whenignited, it tarnishes. It is easily dissolved by nitric acid, but veryslowly by dilute sulphuric or hydrochloric acid, producing hydrogen. 

_Protoxide of Nickel _(NiO). --It is in the form of small greyish-blackoctahedrons, or a dark, greenish-grey powder. Its hydrate is a greenpowder. Both are unalterable in the air, and are soluble in nitric, sulphuric, and hydrochloric acids, to a green liquid. The protoxide isthe base of the salts of nickel, which in the anhydrous state areyellow, and when hydrated are green. The soluble neutral salts changeblue litmus paper to red. By ignition in the oxidation flame, protoxide of nickel is unaltered. In the reduction flame and uponcharcoal, it becomes reduced, and forms a grey adherent powder, whichis infusible, and presents the metallic lustre by compression, and ismagnetic. Borax dissolves it in the oxidation flame very readily to aclear bead, of a reddish-violet or dark yellow color, but yellow orlight red when cold. If there is but a small quantity of the oxidepresent, it is colorless. If more of the oxide be present, the bead isopaque and dark brown, and appears, while cooling, transparent anddark red. By the addition of a salt of potassa (the nitrate orcarbonate) a blue or a dark purple colored bead is produced. The boraxbead, in the reduction flame, is grey, turbid, or completely opaquefrom the reduced metallic particles. After a continued blast, the beadbecomes colorless, although the particles are not fused. If the nickelcontains cobalt, it will now be visible with its peculiar blue color. Upon charcoal, and by the addition of some tin, the reduction of theoxide of nickel is easily effected, while the reduced nickel fuseswith the tin. 

The oxide of nickel is dissolved by microcosmic salt in the oxidationflame to a clear bead, which appears reddish while hot, but yellow andsometimes colorless when cooling. If a considerable quantity of nickelbe present the heated bead is of a brown color, but orange whencooled. In the reduction flame, and upon platinum wire, the color ofthe bead is orange when cold; but upon charcoal, and with the additionof a little tin, the bead appears grey and opaque. After beingsubmitted to the blowpipe flame all the nickel is reduced, and thebead becomes colorless. 

Carbonate of soda does not affect it in the oxidation flame, but inthe reduction flame and upon charcoal, it is absorbed and reduced, andremains, after washing off the carbon, as a white metallic powder, which is infusible, and has a greater attraction for the magnet thaniron. 

_Sesquioxide of Nickel_ (Ni^{2}O^{3}). --It is in the form of a blackpowder, and does not combine with other substances, unless it isreduced to the protoxide. It exhibits before the blowpipe the samebehavior as the protoxide. 

GROUP SIXTH. --ZINC, CADMIUM, ANTIMONY, TELLURIUM. 

The substances of this group can be reduced upon charcoal by fusionwith carbonate of soda, but the reduced metals are volatilized, andcover the charcoal with sublimates. 

(_a. _) _Zinc_ (Zn). --This metal is found in considerable abundance, but never occurs in the pure metallic state, but in combination withother substances, chiefly as sulphide in zinc blende, as carbonate incalamine, and as the silicate in the kieselzinc ore; also, withsulphuric acid, the "vitriol of zinc. "

Zinc is of a bluish-white color and metallic lustre, is crystallineand brittle when heated 400°F. , but malleable and ductile between 200°and 300°. It will not oxidize in dry air, but tarnishes if exposed toair containing moisture, first becomes grey, and then passes into thewhite carbonate. It decomposes in water at a glowing heat. It isdissolved by diluted acids, while hydrogen is eliminated. It melts atabout 775°, and distills when exposed to a white heat in a closevessel. When heated over 1000° in the open air, it takes fire, andburns with a bluish-white light, and with a thick white smoke of oxideof zinc. 

_Oxide of Zinc_ (ZnO). --In the pure state, oxide of zinc is a whitepowder, infusible, and not volatile. It is readily soluble in acidsafter being heated strongly. Its soluble neutral salts, when dissolvedin water, change blue litmus paper to red. Its salts, with organicacids, are decomposed by ignition, and the carbonate of zinc remains. 

The oxide of zinc turns yellow by being ignited in the oxidationflame, but it is only visible by daylight; this color changes to whitewhen cold. It does not melt, but produces a strong light, and it isnot volatile. 

It disappears gradually in the flame of reduction, while a white smokesublimates upon the charcoal. This sublimate is yellow while hot, butchanges to white when cold. The cause of this is, that the oxide isreduced, is volatilized, and re-oxidized, by going through theexternal flame in the form of a metallic vapor. 

Borax dissolves oxide of zinc in the flame of oxidation easily to aclear bead, which is yellow while hot, and colorless when cold. Thebead becomes, by the addition of more oxide, enamelled, while cooling. If the bead is heated with the intermittent flame, it is milk-whitewhen cold. When heated in the flame of reduction upon platinum wire, the bead at first appears opaque, and of a greyish color, but becomesclear again after a continued blast. 

When heated upon charcoal in the reduction flame, it is reduced to ametal; but, at the same moment, is volatilized, and sublimes as oxideof zinc upon the charcoal, about one line's distance from the assay. This is likewise the case with the microcosmic salt, except that it ismore easily volatilized in the reduction flame. 

Carbonate of soda does not dissolve the oxide of zinc in the flame ofoxidation. In the reduction flame and upon charcoal, the oxide of zincis reduced to the metallic state, and is volatilized with a whitevapor of the zinc oxide, which sublimes on the charcoal and exhibits ayellow color while hot, and which changes to white when cold. By astrong heat the reduced zinc burns with a white flame. 

Moistened with a solution of cobalt oxide, and heated strongly in theflame of oxidation, zinc oxide becomes of a yellowish-green colorwhile hot, and changes to a beautiful green color when cold. 

(_b. _) _Cadmium_ (Cd). --This is one of the rare metals. It occurs incombination with sulphur in _greenockite_, and in some ores of zinc. It was detected first in the year 1818, and presents itself as atin-white metal of great lustre, and susceptible of a fine polish. Ithas a fibrous structure, crystallizes easily in regular octahedrons, presenting often the peculiar arborescent appearance of the fern. Itis soft, but harder and more tenacious than tin; it can be bent, filed, and easily cut: it imparts to paper a color like that of lead. It is very malleable and ductile, and can be hammered into thinleaves. It is easily fused, and melts before it glows (450°). At atemperature not much over the boiling point of mercury, it begins toboil, and distills, the vapor of the metal possessing no peculiarodor. It is unalterable in the air for a long time, but at length ittarnishes and presents a greyish-white, half metallic color. Thismetal easily takes fire when heated in the air, and burns with abrownish-yellow vapor, while it deposits a yellow sublimate uponsurrounding bodies. It is easily soluble in acids with the escape ofhydrogen, the solutions being colorless. Its salts, soluble in water, are decomposed by ignition in free air. Its soluble neutral saltschange blue litmus paper to red. The salts, insoluble in water, arereadily dissolved in acids. 

_Oxide of Cadmium_ (CdO). --This oxide is of a dark orange color. Itdoes not melt, and is not volatile, not even at a very hightemperature. Its hydrate is white, loses in the heat its hydraticwater, and absorbs carbonic acid from the air when it is kept in openvessels. 

Cadmium oxide is unaltered when exposed upon platinum wire in theflame of oxidation. When heated upon charcoal in the flame ofreduction it disappears in a very short time, while the charcoal iscoated with a dark orange or yellow powder, the color of which is morevisible after it is cooled. The portions of this sublimate furthestfrom the assay present a visible iridescent appearance. This reactionof cadmium is so characteristic and sensitive that minerals (forinstance, calamine, carbonate of zinc) which contains from one to fiveper cent. Of carbonate of cadmium, will give a dark yellowish ring ofcadmium oxide, a little distance from the assay, after being exposedfor a few moments to the flame of reduction. This sublimate is morevisible when cold, and is produced some time previous to the reductionof the zinc oxide. If a vapor of the latter should appear, itindicates that it has been exposed too great a length of time to theflame. 

Borax dissolves a considerable quantity of cadmium oxide upon aplatinum wire to a clear yellow bead, which, when cold, is almostcolorless. If the bead is nearly saturated with the cadmium oxide, itappears milk-white when intermittingly heated. If the bead iscompletely saturated, it retains its opalescent appearance. Uponcharcoal, and in the flame of reduction, the bead intumesces, thecadmium oxide becomes reduced to metal; this becomes volatilized andre-oxidized, and sublimes upon the charcoal as the yellow cadmiumoxide. 

In the oxidation flame, microcosmic salt dissolves a large quantity ofit to a clear bead, which, when highly saturated and while hot, isyellowish colored, but colorless when cold. By complete saturation, the bead is enamel-white when cold. 

Upon charcoal, in the flame of reduction, the bead is slowly and onlypartially reduced, a scanty sublimate being produced on the charcoal. The addition of tin promotes the reduction. 

Carbonate of soda does not dissolve cadmium oxide in the oxidationflame. In the reduction flame, upon charcoal, it is reduced to metal, and is volatilized to a red-brown or dark, red sublimate of cadmiumoxide upon the charcoal, at a little distance from the assay thecharcoal presenting the characteristic iridescent appearance. Thisreaction is still more sensitive if the cadmium oxide is heated _perse_ in the reduction flame. 

_Antimony_ (Sb). --This metal is found in almost every country. Itprincipally occurs as the tersulphide (SbS^{3}), either pure orcombined with other sulphides, particularly with basic sulphides. Sometimes it occurs as the pure metal, and rarer in a state ofoxidation as an antimonious acid and as the oxysulphide. 

In the pure state, antimony has a silver-white color, with muchlustre, and presents a crystalline structure. The commercial andimpure metal is of a tin-white color, and may frequently be split inparallel strata. It is brittle and easily pulverized. It melts at alow red heat (810°), is volatilized at a white heat, and can bedistilled. At common temperatures it is not affected by the air. At aglowing heat it takes fire, and burns with a white flame, and withwhite fumes, forming volatile antimonious acid. Common acids oxidizeantimony, but dissolve it slightly. It is soluble in aqua regia(nitro-hydrochloric acid). 

_Sesquioxide of Antimony_ (Sb^{2}O^{3}). --In the pure state this oxideis a white powder, is fusible at a dull red heat to a yellow liquid, which, after cooling, is greyish-white and crystalline. If it isheated excluded from the air, it can be volatilized completely; itsublimes in bright crystals having the form of needles. It occurssometimes in nature as white and very bright crystals. It takes firewhen heated in the open air, and burns with a white vapor toantimonious acid. It fuses with the ter-sulphide of antimony to a redbead. It is distinguished from the other oxides of antimony by thereadiness with which it is reduced to the metallic state uponcharcoal, and by its easy fusibility and volatility. 

The sesquioxide is the base of some salts--for instance, the tartaremetic. It is not soluble in nitric acid, but is soluble inhydrochloric acid. This solution becomes milky by the addition ofwater. A part of the salts of the sesquioxide of antimony aredecomposed by ignition. The haloid salts are easily volatilized, without decomposition. Its soluble neutral salts change blue litmuspaper to red, and are converted, by admixture of water, intoinsoluble basic and soluble acid salts. 

Antimonious acid (antimoniate of sesquioxide of antimony, Sb^{2}O^{3}+ Sb^{2}O^{5}) is of a white color, but, when heated, of a lightyellow color, but changes to white again when cold. It is infusibleand unaltered by heat. It forms a white hydrate, and both areinsoluble in water and nitric acid. It is partly soluble inhydrochloric acid, with the application of heat. The addition of watercauses a precipitate in this solution. 

_Antimonic Acid _(Sb^{2}O^{5}). --In the pure state this acid is alight yellow-colored powder. Its hydrate is white, and is insoluble inwater and nitric acid. It is sparingly soluble in hot concentratedhydrochloric acid. It forms salts with every base, some of which areinsoluble, and others sparingly so. Notwithstanding that antimonicacid is insoluble in water, it expels the carbonic acid from thesolutions of the carbonates of the alkalies. Antimonic acid and itshydrate changes moistened blue litmus paper to red. 

_Behavior of Antimony and its Oxides before the Blowpipe. _

_Metallic Antimony_ fuses easily upon charcoal. When heated toglowing, and then removed from the flame, it continues to glow forawhile, and produces a thick white smoke. The vapor crystallizesgradually, and coats the assay with small crystals which iridesce likemother of pearl (sesquioxide of antimony). It is not volatile at thetemperature of melted glass. Ignited in an open glass tube, it burnsslowly with a white vapor, which condenses upon the cool part of thetube, and exhibits some indications of crystallization. This vaporconsists of the sesquioxide, and can be driven by heat from one placeto another, without leaving a residue. If the metallic antimonycontains sulphide of antimony, there is a corresponding portion ofantimonious acid produced, which remains as a white sublimate afterthe sesquioxide is removed. 

_Sesquioxide of antimony_ melts easily, and sublimes as a white vapor. It may be prepared by precipitating and drying. When heated, it takesfire previous to melting, glows like tinder, and is converted intoantimonious acid, which is now infusible. When heated upon charcoal inthe flame of reduction, it is reduced to the metallic state, andpartly volatilized. A white vapor sublimates upon the charcoal, whilethe external flame exhibits a greenish-blue color. Antimonious acid isinfusible, produces a strong light, and is diminished in volume whenheated in the external flame, during which time a dense white vaporsublimes upon the charcoal. It is not, however, in this manner reducedto the metallic state like the sesquioxide. 

_Antimonic acid_, when first heated, becomes white, and is convertedinto antimonious acid. Hydrated antimonic acid, which is originallywhite, appears at first yellow while giving off water, and thenbecomes white again, while oxygen is expelled, and it is convertedinto antimonious acid. 

The oxides of antimony produce, with blowpipe reagents, the followingreactions: borax dissolves oxides of antimony in the oxidation flamein considerable quantity to a clear bead, which is yellow while hot, but colorless when cold. If the bead is saturated, a part of the oxideis volatilized as a white vapor. Upon charcoal, in the oxidationflame, it is completely volatilized, and the charcoal is covered witha white sublimate. Heated upon charcoal in the reducing flame, thebead is of a greyish color, and partially, if not wholly opaque, fromthe presence of reduced metallic particles. A continued heat willvolatilize them, and the bead becomes clear. The addition of tinpromotes the reduction. 

Microcosmic salt dissolves the compounds of antimony in the flame ofoxidation with intumescence, to a clear light-yellow colored bead, which when cold is colorless. Heated upon charcoal in the reductionflame, the bead is first turbid, but soon becomes transparent. Theaddition of tin renders the bead greyish while cooling, but acontinued blast renders it transparent. Soda dissolves the compoundsof antimony upon platinum wire in the oxidation flame, to a clearcolorless bead, which is white when cold. 

Upon charcoal, both in the oxidation and reduction flames, theantimony compounds are readily reduced to the metal, which isimmediately volatilized, and produces a white incrustation of oxide ofantimony upon the charcoal. If the antimony compounds are heated uponcharcoal in the flame of reduction, with a mixture of carbonate ofsoda and cyanide of potassium (KCy), there are produced small globulesof metallic antimony. At the same time, a part of the reduced metal isvolatilized (this continues after the assay is removed from the flame)and re-oxidized. A white incrustation appears upon the charcoal, andthe metallic globules are covered with small white crystals. If thiswhite sublimate upon the charcoal is moistened with a solution ofcobalt-oxide, and exposed to the reduction flame, a part of it isvolatilized, while the other part passes into higher oxidation, andremains, after cooling, of a dirty dark-green color. 

(_d. _) _Tellurium_ (Te). --This is one of the rare metals. It occursvery seldom in the metallic state, but often with bismuth, lead, silver, and gold. Tellurium, in the pure state, is silver-white, verybright, of a foliated or lamellar structure, brittle, and easilytriturated. It is inclined to crystallize. It is soluble inconcentrated sulphuric acid without oxidation. The solution is of afine purple color, and gives a precipitate with the addition of water. 

_Tellurium in the Metallic form. _--By the aid of heat it is oxidizedin sulphuric acid, a portion of the oxygen of the acid oxidizing themetal, while sulphurous acid gas escapes. This solution is colorless, and is tellurous acid, dissolved in sulphuric acid. It melts at a lowred heat, and volatilizes at a higher temperature. If tellurium isheated with free access of air, it takes fire, and burns with a bluecolor, the flame being greenish at the edges, while a thick whitevapor escapes, which has a feeble acidulous odor. 

_Tellurous Acid_ (TeO^{2}) is of a fine, granulous, crystalline orwhite earthy mass, which is partly soluble in water. The solution hasa strong metallic taste, and an acid reaction upon litmus paper. Heated in a tube closed at one end until it begins to glow, it fusesto a yellow liquid which is colorless, crystalline, and opaque whencold. Beads of it remain usually transparent like glass. Heated uponplatinum wire in the flame of oxidation, it melts, and is volatilizedas a white vapor. When heated upon charcoal in the oxidation flame, itmelts, and is reduced to the metallic state, but volatilizes and asublimate of white tellurous acid is formed upon the charcoal. Theedge of this deposit is usually red or dark-yellow. 

Heated upon charcoal in the flame of reduction, it is rapidly reduced, the external flame exhibiting a bluish-green color. 

Borax dissolves it in the oxidation flame upon platinum wire to aclear colorless bead which turns grey when heated upon charcoal, through the presence of reduced metallic particles. Upon charcoal, inthe reduction flame, the bead is grey, caused by the reduced metal. After a continued blast, tellurium is completely volatilized, and thebead appears clear again, while a white sublimate is deposited uponthe charcoal. 

With microcosmic salt, the same reactions are produced. 

With carbonate of soda, tellurous acid fuses upon platinum wire to aclear colorless bead, which is white when cold. Upon charcoal it isreduced, and forms _tellur-sodium_, which is absorbed by the charcoal, and metallic tellurium, which is volatilized, and deposits upon thecharcoal a white incrustation (tellurous acid). 

If tellurous acid, finely powdered charcoal, and carbonate of soda aremixed together, and the mixture be well ignited in a closed tube, until fusion is effected, and a few drops of boiled water are broughtinto the tube, they are colored purple, indicating the presence of_tellur-sodium. _

_Telluric Acid _(TeO^{3}) forms six-sided prismatic crystals. It hasnot an acid, but rather a metallic taste. It changes blue litmus paperto red; is slowly soluble in water, and rather sparingly. Exposed toa high temperature, but not until glowing, the crystalline acid losesits water, and acquires an orange color, but still it preserves itscrystalline form, although no longer soluble in water, and is in factso much changed in its properties as to present the instance of anisomeric modification. 

If telluric acid is heated gently in a closed tube, it loses water andturns yellow. Heated still more strongly, it becomes milk-white, oxygen is expelled, and it is converted into tellurous acid. Thepresence of oxygen can be recognized by the more lively combustionwhich an ignited splinter of wood undergoes when held in it. Telluricacid produces the same reactions with the blowpipe reagents astellurous acid. 

SEVENTH GROUP. --LEAD, BISMUTH, TIN. 

The oxides of these metals are also reduced to the metallic state byfusion with soda upon charcoal in the flame of reduction, but they arevolatilized only after a continued blast, and a sublimate is thrownupon the charcoal. 

(_a. _) _Lead_ (Pb). --This metal occurs in considerable quantity innature, chiefly as galena or lead-glance (sulphide of lead). Likewise, but more rarely, as a carbonate; also as a sulphate, and sometimescombined with other acids and metals. 

In the metallic state, lead is of a bluish-grey color, high lustre, and sp. Gr. 11. 4. It is soft, and communicates a stain to paper. It ismalleable, ductile, but has very little tenacity. It melts at about612°. Exposed to the air it soon tarnishes, being covered with a greymatter, which some regard as a suboxide (Pb^{2}O), and others assimply a mixture of lead and protoxide. At a glowing heat it isoxidized to a protoxide, and at a white heat it is volatilized. It isinsoluble in most acids. It is, however, soluble in nitric acid, butwithout decomposing water. 

(_L. _) _Protoxide of Lead_ (PbO). --It is an orange-colored powder, which melts at a glowing temperature, and forms a lamellar mass aftercooling. Protoxide of lead absorbs oxygen from the atmosphere whilemelting, which is given off again by cooling. Being exposed for alonger while to the air, it absorbs carbonic acid and water, andbecomes white on the surface. It is soluble in nitric acid and causticalkalies. It forms with most acids insoluble salts. It is slightlysoluble in pure water, but not in water which contains alkaline salts. This hydrate is white. 

([beta]. ) _Red Oxide of Lead_ (PbO^{2}, PbO). --It forms a puce-coloredpowder. It is insoluble in caustic alkalies. Hydrochloric aciddissolves it and forms a yellow liquid, which is soon decomposed intochloride of lead and chlorine. It is reduced by ignition to theprotoxide. 

([gamma]. ) _Peroxide of Lead _(PbO^{2}). --It is a dark-brown powder. It yields with hydrochloric acid the chloride of lead and chlorinegas. When heated it liberates oxygen, and is reduced to the protoxide. 

Lead combinations give the following reactions before the blowpipe:Metallic lead tarnishes when heated in the oxidation flame, and isinstantly covered with a grey matter, consisting of the protoxide andthe metal. It fuses quickly, and is then covered with ayellowish-brown protoxide until all the lead is converted into theprotoxide, which melts to a yellow liquid. In the reduction flame andupon charcoal, it is volatilized, while the charcoal becomes coveredwith a yellow sublimate of oxide. A little distance from the assay, this sublimate appears white (carbonate of lead). Protoxide of leadmelts in the flame of oxidation to a beautiful dark yellow bead. Inthe flame of reduction, and upon charcoal, it is reduced withintumescence to metallic lead, which is volatilized by a continuedblast, and sublimates on charcoal, as mentioned above. 

Red oxide of lead turns black when heated in the glass tube closed atone end, and liberates oxygen, which is easily detected by theintroduction of an ignited splinter, when a more lively combustion ofthe wood proves the presence of uncombined oxygen. The red oxide inthis case is reduced to the protoxide. Heated upon platinum foil, itfirst turns black, is reduced to the protoxide, and melts into a darkyellow liquid. In the reduction flame, upon charcoal, it is reduced tothe metal with intumescence. After a continued blast, a yellowsublimate of protoxide is produced upon the charcoal, and at a littledistance off, around this sublimate, a white one of carbonate of leadis produced. This sublimate disappears when touched by the flame ofreduction, while it communicates an azure blue-tinge to the externalflame. This is likewise the case with the peroxide of lead. 

The different oxides of lead produce with the blowpipe reagents thesame reactions. 

_Borax_ dissolves lead compounds with the greatest readiness uponplatinum wire in the oxidation flame to a transparent bead, which isyellow when hot, but colorless after being cooled. With the additionof more of the lead oxide, it becomes opalescent. When heated by theintermittent flame, and with still more of the oxide, it acquires ayellow enamel after cooling. Heated upon charcoal, in the flame ofreduction, the bead spreads and becomes opaque. After a continuedblast, all the oxide is reduced with effervescence to metallic lead, which melts and runs towards the edges of the bead, while the beadagain becomes transparent. 

_Microcosmic Salt_ dissolves oxides of lead upon platinum wire in theflame of oxidation easily to a clear, colorless bead, which appears, when highly saturated, yellow while hot. A saturated bead becomesenamel-like after cooling. The bead appears in the flame of reduction, and upon charcoal, of a greyish color and dull. By the addition ofmore oxide, a yellow sublimate of protoxide is produced upon thecharcoal. By the addition of tin, the bead appears of a darker grey, but it is never quite opaque. 

_Carbonate of Soda_ dissolves oxide of lead in the flame of oxidationupon platinum wire quite readily to a transparent bead, which becomesyellow when cooling, and is opaque. Upon charcoal in the flame ofreduction, it is rapidly reduced to metallic lead, which yields, after a continued blast, a yellow sublimate of oxide upon thecharcoal. 

(_b. _) _Bismuth_ (Bi). --This metal occurs mostly in the metallicstate, and less frequently as the sulphide. In the pure metallicstate, it is of a reddish-white color and great lustre. Itcrystallizes in cubes. It is brittle, and may be readily pulverized. It melts at 476°, and is volatilized at a white heat. It is soluble innitric acid, and forms the nitrate of bismuth. 

([alpha]. ) _Oxide of Bismuth _(Bi^{2}O^{3}). --This oxide is a lightyellow powder, fusible at a red heat, insoluble in caustic potash andammonia. It is the base of the salts of bismuth. Its hydrate is white, and easily soluble in acids. The addition of water causes thesesolutions to become milky, because they are decomposed into a solubleacidulous and an insoluble basic salt of bismuth. 

([beta]. ) _Peroxide of Bismuth_ (BiO^{2}) is a dark-colored powder, completely soluble in boiling nitric acid, and yielding oxygen;produces, with hydrochloric acid, chlorine gas. It can be heated up tothe temperature of 620° without being decomposed; but, exposed to atemperature of 630° it yields oxygen. Mixed with combustiblesubstances, it glows with brightness. 

([gamma]. ) _Bismuthic Acid _(Bi^{2}O^{5}) is a brown powder similar tothe peroxide, but is converted by boiling nitric acid into a green, scarcely soluble substance (Bi^{2}O^{3}, Bi^{2}O^{5}). Its hydrate isof a red color. 

BLOWPIPE REACTIONS. --Metallic bismuth is converted, when exposed uponplatinum wire to the flame of oxidation, into a dark brown oxide, which turns light yellow while cooling. It is slowly volatilized whenheated, and a yellow sublimate of oxide is produced upon the charcoal. 

Oxide of bismuth melts upon platinum foil in the flame of oxidationvery easily into a dark-brown liquid, which changes to a light yellowwhile cooling. By too strong a heat, it is reduced and penetrates theplatinum foil. 

Upon charcoal, in the flame of oxidation and of reduction, it isreduced to metallic bismuth, which melts into one or more globules. By a continued blast they are slowly volatilized, and produce a yellowsublimate of oxide upon the charcoal, beyond which a white sublimateof carbonate of bismuth is visible. These sublimates disappear in theflame of reduction, but without communicating any color to it. 

_Borax_ dissolves oxide of bismuth upon platinum wire, in the flame ofoxidation, easily to a clear yellow bead, which appears colorlessafter cooling. By the addition of more oxide, the hot bead becomesorange. It turns more yellow while cooling, and when cool isopalescent. Upon charcoal in the flame of reduction, the bead becomesturbid and greyish colored. The oxide is reduced with intumescence tothe metallic state, and the bead becomes clear again. The addition oftin promotes the reduction. 

_Microcosmic Salt_ dissolves oxide of bismuth upon platinum wire, inthe flame of oxidation, to a yellow bead, which becomes colorlessafter cooling. By the addition of more oxide, the bead isyellowish-brown while hot, and colorless after cooling, but not quitetransparent. This bead becomes enamelled when heated by theintermittent flame; also, by the addition of still more of the oxide, after it is cooled. 

Upon charcoal, in the flame of reduction, and particularly with theaddition of tin, the bead is colorless and transparent while hot, butwhile cooling becomes of a dark-gray color and opaque. 

Oxide of bismuth is reduced, by fusion with carbonate of soda, as wellin the oxidating as in the reducing flame, instantly to metallicbismuth. 

As the above mentioned higher oxides of bismuth are converted byignition into oxide of the metal and free oxygen, they have the samebehavior before the blowpipe. 

As bismuth occurs mostly in the metallic form, it is necessary to knowhow to distinguish it from metals similar to it. Its brittlenessdistinguishes it from lead, zinc and tin, as they are readilyflattened by a stroke of the hammer, while bismuth is broken topieces. Bismuth, in this latter respect, might perhaps be mistakenfor antimony or tellurium; but, by the following examination, it iseasy to separate bismuth from antimony or tellurium. 

1. Neither bismuth nor antimony sublimates when heated in a glass tubeclosed at one end. At a temperature which is about to fuse the glass, tellurium yields a small quantity of a white vapor (some tellurium isoxidized to tellurous acid by the oxygen of the air in the tube). After that, a grey metallic sublimate settles on the sides of thetube. 

2. Heated in an open tube, antimony yields a white vapor, which coatsthe inside of the glass tube, and can be driven by heat from one partof the tube to another without leaving a residue. The metallic globuleis covered with a considerable quantity of fused oxide. Telluriumproduces, under the same circumstances, an intense vapor, and depositson the glass a white powder, which melts by heat into globules thatrun over the glass. The metallic globules are covered by fused, transparent, and nearly colorless oxide, which becomes white whilecooling. By a high temperature, and with little access of air, metallic tellurium sublimes with the deposition of a grey powder. Bismuth produces, under similar treatment, scarcely any vapor, unlessit is combined with sulphur. The metal is enveloped by fused oxide ofa dark yellow color, which appears light yellow after being cooled. Itacts upon the glass, and dissolves it. 

3. Upon charcoal, exposed to the blowpipe flame, the three metals arevolatilized, and yield a sublimate upon the charcoal. That of antimonyis white, while those of bismuth and tellurium are dark yellow. Byexposing them to the flame of reduction, the sublimate of telluriumdisappears and communicates an intense green color to the flame. Theantimony incrustation gives a feeble greenish-blue color, while thesublimate of bismuth gives no perceptible color in the light. It is, however, worthy of notice that if the operation takes place in thedark, a very pale blue flame will be seen with the bismuth. 

(_c. _) _Tin_ (Sn). --This metal does not occur in nature in themetallic state, very seldom in the sulphide, but chiefly in the oxide(tinstone). In the metallic state it is silver-white, possesses a veryhigh lustre, is soft (but harder than lead), ductile, but has not muchtenacity, and it is very malleable. The metal when it is cast gives apeculiar creaking noise when twisted or bent, which proceeds from thecrystalline structure of the metal. This crystallization is quiteclearly manifested by attacking the surface of the metal, or that oftin plate, with acids. 

Tin is very slightly tarnished by exposure to the air. It fuses at442°, and becomes grey, being a mixture of the oxide and the metal. Ata high temperature even, tin is but little subject to pass off asvapor. It is soluble in aqua regia, and with the liberation ofhydrogen, in hot sulphuric and hydrochloric acids, and in cold dilutenitric acid, without decomposing water, or the production of a gas, while nitrate of tin and nitrate of ammonia are formed. Concentratednitric acid converts tin into insoluble tin acids. 

([alpha]. ) _Protoxide of Tin_ (SnO) is a dark-grey powder. Its hydrateis white, and is soluble in caustic alkalies. When this solution isheated, anhydrous crystalline black protoxide is separated. Thesoluble neutral salts of tin-protoxide are decomposed by the additionof water, and converted into acid soluble, and basic insoluble salts. 

When protoxide of tin is ignited with free access of air, it takesfire and is converted with considerable intensity into the acids, producing white vapors. This is likewise the case if it is touched bya spark of fire from steel. The hydrate of the protoxide of tin can beignited by the flame of a candle, and glows like tinder. 

([beta]. ) _Sesquioxide of Tin_ (Sn^{2}O^{3}) is a greyish-brownpowder. Its hydrate is white, with a yellow tinge. It is soluble inaqua ammonia and in hydrochloric acid; this solution forms withsolution of gold the "purple of Cassius. "

([gamma]. ) _Stannic Acid_ (peroxide, SnO^{2}). --This acid occurs innature crystallized in quadro-octahedrons, of a brown or an intenseblack color, and of great hardness (tinstone). Artificially prepared, it is a white or yellowish-white powder. It exists in two distinct orisomeric modifications, one of which is insoluble in acids (naturaltin-acid) while the other (tin-acid prepared in the wet way) issoluble in acids. By ignition the soluble acid is converted into theinsoluble. Both modifications form hydrates. 

_Reactions before the Blowpipe. _--Metallic tin melts easily. It iscovered in the flame of oxidation into a yellowish-white oxide, whichis carried off sometimes by the stream of air which propels the flame. In the reduction flame, and upon charcoal, melting tin retains itsmetallic lustre, while a thin sublimate is produced upon the charcoal. This sublimate is light-yellow while hot, and gives a strong light inthe flame of oxidation, and turns white while cooling. This sublimateis found near to the metal, and cannot be volatilized in the oxidationflame. In the flame of reduction it is reduced to metallic tin. Sometimes this incrustation is so imperceptible that it can scarcelybe distinguished from the ashes of the charcoal. If such be the case, moisten it with a solution of cobalt, and expose it to the flame ofoxidation, when the sublimate will exhibit, after cooling, abluish-green color. 

Protoxide of tin takes fire in the flame of oxidation, and burns withflame and some white vapor into tin acid, or stannic acid. In a strongand continued reduction flame, it may be reduced to metal, when thesame sublimate above mentioned is visible. The sesquioxide of tinbehaves as the above. 

Stannic acid, heated in the flame of oxidation, does not melt and isnot volatilized, but produces a strong light, and appears yellowishwhile hot, but changing as it cools to a dirty-yellow white color. Ina strong and continued flame of reduction, it may be reduced likewiseto the metallic state, with the production of the same sublimate asthe above. 

_Borax_ dissolves tin compounds in the flame of oxidation, and uponplatinum wire, very tardily, and in small quantity, to a transparentcolorless bead, which remains clear after cooling, and also whenheated intermittingly. But if a saturated bead, after being completelycool, is exposed again to the flame of oxidation, at a low red heat, the bead while cooling is opaque, loses its globular form, andexhibits an indistinct crystallization. This is the case too in theflame of reduction, but if the bead is highly saturated, a part of theoxide is reduced. 

_Microcosmic Salt_ dissolves the oxides in the flame of reduction verytardily in a small quantity to a transparent colorless bead, whichremains clear while cooling. If to this bead sesquioxide of iron isadded in proper proportion, the sesquioxide loses its property ofcoloring the bead, but of course an excess of the iron salt willcommunicate to the bead its own characteristic color. In the flame ofreduction no further alteration is visible. 

Tin-oxides combine with carbonate of soda, in the flame of oxidationupon platinum wire, with intumescence to a bulky and confused mass, which is insoluble in more soda. Upon charcoal, in the reductionflame, it is easily reduced to a metallic globule. Certain compoundsof tin-oxides, particularly if they contain tantalum, are by fusionwith carbonate of soda reduced with difficulty; but by the addition ofsome borax, the reduction to the metallic state is easily effected. 

Tin-oxides exposed to the oxidation flame, then moistened with asolution of cobalt, and exposed again to the flame of oxidation, willexhibit, after having completely cooled, a bluish-green color. 

EIGHTH GROUP. --MERCURY, ARSENIC. 

These two metals are volatilized at a temperature lower than that of ared heat, and produce, therefore, no reactions with borax andmicrocosmic salt. Their oxides are easily reduced to the metallicstate. 

(_a. _) _Mercury_ (Hg). --This metal occurs in nature chiefly combinedwith sulphur as a bisulphide. 

It occurs still more rarely in the metallic form, or combined withsilver, selenium, or chlorine. 

Mercury, in the metallic state, has a strong lustre, and is liquid atordinary temperatures, whereby it is distinguished from any othermetal. It freezes at 40° and boils at 620°, but it evaporates atcommon temperatures. Pure mercury is unalterable. Upon being exposedto the air, it tarnishes only by admixture with other metals, turnsgrey on the surface, and loses its lustre. It is soluble in coldnitric acid and in concentrated hot sulphuric acid, but not inhydrochloric acid. 

([chi]. ) _Protoxide of Mercury_ (Hg^{2}O). --It is a black powder, which is decomposed by ignition into metallic mercury and oxygen. Bydigestion with certain acids, and particularly with caustic alkalies, it is converted into metallic mercury and peroxide. Some neutral saltsof the protoxide are only partly soluble in water, as they areconverted into basic insoluble and acid soluble salts. 

Protoxide of mercury is completely insoluble in hydrochloric acid. Itsneutral salts change blue litmus paper to red. 

([beta]. ) _Peroxide of Mercury_ (HgO). --This oxide exists in twoallotropic modifications. One is of a brick-red color, and the otheris orange. Being exposed to heat, they turn black, but regain theirrespective colors upon cooling. They are decomposed at a hightemperature into metallic mercury and oxygen. They yield with acidstheir own peculiar salts. 

Mercury, in the metallic form, can never be mistaken for any othermetal in consequence of its fluid condition at ordinary temperatures. 

Exposed to the blowpipe flame, it is instantly volatilized. This isalso the case with it when combined with other metals. The oxides ofmercury are, in the oxidation and reduction flames, instantly reducedand volatilized. They do not produce any alteration with fluxes, asthey are volatilized before the bead melts. Heated with carbonate ofsoda in a glass tube closed at one end, they are reduced to metallicmercury, which is volatilized, and condenses upon a cool portion ofthe tube as a grey powder. By cautious knocking against the tube, orby rubbing with a glass rod, this sublimate can be brought togetherinto one globule of metallic mercury. Compounds of mercury can be mostcompletely reduced by a mixture of neutral oxalate of potassa andcyanide of potassium. If the substance under examination contains sucha small quantity of mercury that it cannot be distinguished byvolatilization, a strip of gold leaf may be attached to an iron wire, and introduced during the experiment in the glass tube. The smallesttrace of mercury will whiten the gold leaf in spots. 

(_b. _) _Arsenic_ (As). --This metal occurs in considerable quantity innature, chiefly combined with sulphur or metals. 

Arsenic, in the metallic state, is of a whitish-grey color, highlustre, and is crystalline, of a foliated structure, and is so brittlethat it can be pulverized. It does not melt, but is volatilized at356°. Its vapor has a strong alliaceous odor. Arsenic sublimes inirregular crystals. By exposure to the air it soon tarnishes, and iscoated black. Being mixed with nitrate of potassa and inflamed, itdetonates with vehemence. Mixed with carbonate of potassa, it isinflamed by a stroke of the hammer, and detonates violently. 

Heated in oxygen gas, it is inflamed, and burns with a pale blue flameto arsenious acid. 

([beta]. ) _Arsenious Acid_ (AsO^{3}). --This acid crystallizes inoctahedrons, or, when fused, forms a colorless glass, which finallybecomes opaque and enamel-like, or forms a white powder. It sublimeswithout change or decomposition. When heated for a longer while belowthe temperature of sublimation, it melts into a transparent, colorless, tough glass. The opaque acid is sparingly soluble in coldwater, and still more soluble in hot water. It is converted, bycontinued boiling, into the transparent acid, which is much moresoluble in water. Arsenious acid is easily dissolved by causticpotassa. It is also soluble in hydrochloric acid. This acid occursassociated with antimonious acid, protoxide of tin, protoxide of lead, and oxide of copper. It occurs likewise in very small quantity inferruginous mineral springs. 

([gamma]. )_Arsenic Acid_ (AsO^{5}) is a white mass, which readilyabsorbs moisture and dissolves. It will not volatilize at a low redheat, nor will it decompose. Exposed to a strong heat, it isdecomposed, yielding oxygen, and passing into arsenious acid. 

_Reactions before the Blowpipe. _

Metallic arsenic, heated in a glass tube closed at one end, yields ablack sublimate of a metallic lustre, and at the same time gives outthe characteristic alliaceous odor. This is the case too with alloysof arsenic, if there is a maximum quantity of arsenic present. 

When heated in a glass tube open at both ends, metallic arsenic isoxidized to arsenious acid, which appears as a white crystallinesublimate on the sides of the glass tube. This deposit will occur atsome distance from the assay, in consequence of the great volatilityof the arsenic. The sublimate can be driven from one place upon thetube to another, by a very low heat. Alloys of arsenic are convertedinto basic arseniates of metal oxides, while surplus arsenic isconverted into arsenious acid, which sublimes on the tube. If too mucharsenic is used for this experiment, a dark-brown incrustation willsublime upon the sides of the tube which will give an alliaceoussmell. If this sublimate should be deposited near the assay, then itresembles the white sublimate of arsenious acid. 

Heated upon charcoal, metallic arsenic is volatilized before it melts, and incrusts the charcoal in the flame of oxidation as a white depositof arsenious acid. This sublimate appears sometimes of a greyishcolor, and takes place at some distance from the assay. When heatedslightly with the blowpipe flame, this sublimate is instantly drivenaway, and being heated rapidly in the reduction flame, it disappearswith a light blue tinge, while the usual alliaceous or garlic smellmay be discerned. 

Arsenious acid sublimes in both glass tubes very readily, as a whitecrystalline sublimate. These crystals appear to be regular octahedronswhen observed under the microscope. Upon charcoal it instantlyvolatilizes, and when heated, the characteristic garlic smell may beobserved. 

Arsenic acid yields, heated strongly in a glass tube closed at oneend, oxygen and arsenious acid, the latter of which sublimes in thecool portions of the tube. Compounds of arsenic produce, inconsequence of their volatility, no reactions with fluxes. Beingheated upon charcoal with carbonate of soda, they are reduced tometallic arsenic which may be detected by the alliaceous odor peculiarto all the arsenic compounds when volatilized. 

NINTH GROUP. --COPPER, SILVER, GOLD. 

These metals are not volatile, neither are their oxides. They arereduced to the metallic state, by fusion with carbonate of soda, whenthey melt to a metallic grain. The oxides of silver and gold arereduced _per se_ to the metallic state by ignition. In the reductionof the oxides of this group, no sublimate is visible upon thecharcoal. 

(_a. _) _Copper_ (Cu). --This metal occurs in the metallic state, alsoas the protoxide, and as oxides combined with acids in different salts(carbonate of copper as malachite, etc. ) The sulphide of copper is theprincipal ore of copper occurring in nature. In the metallic state, copper is of a red color, has great lustre and tenacity, is ductileand malleable, and crystallizes in octahedrons and cubes. It melts ata bright red heat, is more difficult than silver to fuse, but fusesmore readily than gold. It absorbs oxygen while melting. There arisesfrom its surface a fine dust of metallic globules, which are coveredwith the protoxide. The surface of the metal is likewise covered withthe protoxide. Copper exposed to moist air tarnishes, and isconverted into hydratic carbonate of copper. When ignited in the openair, it is soon covered with the brownish-red protoxide. 

([chi]. ) _Protoxide of Copper_ (Cu^{2}O). --This oxide occurs innature, crystallized in octahedrons of a ruby-red color, of a lamellarstructure, and transparent. Artificially prepared, it forms a powderof the same color. It is decomposed by dilute acids into salts ofperoxide and metal. It is converted by ignition, with free access ofair, into peroxide. 

([beta]. ) _Oxide of Copper_ (CuO). --This oxide is a dark-brown orblack powder. It is dissolved by acids, with a blue or green-coloredsolution. It is soluble in aqua ammonia, and the solution is of a darkblue color. 

_Reactions before the Blowpipe. _--Oxide of copper exposed uponplatinum wire to the inmost flame (the blue flame), communicates tothe external flame a green color. Heated upon charcoal in theoxidation flame, it melts to a black ball, soon spreads over thecharcoal, and is partially reduced. 

Exposed to the reduction flame, at a temperature which will not meltcopper, it is reduced with a bright metallic lustre, but as soon asthe blast ceases, the surface of the metal becomes oxidized, andappears dark brown or black. If the temperature is continued stillhigher, it melts to a metallic grain. 

_Borax_ dissolves the oxide of copper in the flame of oxidation to aclear green-colored bead, even if the quantity of oxide be quitesmall, but by cooling, the bead becomes blue. In the flame ofreduction upon platinum wire, the bead soon becomes colorless, butwhile cooling presents a red color (protoxide of copper). This bead isopaque, but, if too much of the oxide is added, a part of it isreduced to metal, which is visible by breaking the metallic grain. 

Upon charcoal, the oxide is reduced to the metal, and the bead appearscolorless after cooling. With the addition of some tin, the beadbecomes brownish-red and opaque after cooling. 

_Microcosmic Salt_ dissolves oxide of copper in the flame of oxidationto a green bead, not so intensely colored as the borax bead. In thereduction flame the bead, if pretty well saturated, becomes dark-greenwhile hot, and brownish-red when cool, opaque and enamel-like. If theoxide is so little that no reaction is visible, by the addition ofsome tin, the bead appears colorless while hot, and dark brownish-redand opaque when cold. 

_Carbonate of Soda_ dissolves oxide of copper in the oxidation flameupon platinum wire, to a clear, green bead, which loses its color whencooling, and becomes opaque. 

Upon charcoal, it is reduced to the metal, the soda is absorbed by thecharcoal, and the metallic particles melt with sufficient heat to agrain. 

(_b. _) _Silver_ (Ag). --This metal occurs in nature in the metallicstate, and in combination with other metals, particularly with lead. It also occurs as the sulphide in several mines. It crystallizes incubes and octahedrons; is of a pure white color, great lustre, is verymalleable and ductile, and is softer than copper, but harder thangold. It is not oxidizable, neither at common temperatures nor atthose which are considerably higher. It is soluble in dilute nitricacid, and in boiling concentrated sulphuric acid. 

([chi]. ) _Protoxide of Silver_ (Ag^{2}O). --It is a black powder. It isconverted by acids and ammonia into oxide and metal. 

([beta]. ) _Oxide of Silver_ (AgO). --It is a greyish-brown or blackpowder, and is the base of the silver salts. With aqua ammonia, it isconverted into the black, fulminating silver. 

([gamma]. ) _Superoxide or Binoxide of Silver_ (AgO^{2}). --This oxideoccurs in black needles or octahedral crystals of great metalliclustre. It is dissolved by the oxygen acids with the disengagement ofoxygen gas. 

_Behavior before the Blowpipe. _--When exposed to the flames ofoxidation and reduction, the oxides of silver are instantly reduced tothe metallic state. 

_Borax_ dissolves silver-oxides upon platinum wire in the oxidationflame but partially, while the other portion is reduced, the beadappearing opalescent after cooling, in correspondence to the degree ofsaturation. The bead becomes grey in the flame of reduction, thereduced silver melting to a grain, and the bead is rendered clear andcolorless again. 

_Microcosmic Salt_ dissolves oxides of silver in the flame ofoxidation upon platinum wire to a transparent yellowish bead, whichpresents, when much of the oxide is present, an opalescent appearance. 

In the flame of reduction, the reaction is analogous to that of borax. 

By fusion with carbonate of soda in the oxidation and reductionflames, the silver oxides are instantly reduced to metallic silver, which fuses into one or more grains. 

(_c. _) _Gold_ (Au). --This metal occurs mostly in the metallic state, but frequently mixed with ores, and with other metals. Goldcrystallizes in cubes and octahedrons, is of a beautiful yellow color, great lustre, and is the most malleable and ductile of all the metals. It melts at a higher temperature than copper, gives a green coloredlight when fused, and contracts greatly when cooling. It does notoxidize at ordinary temperatures, nor when heated much above them. Itis soluble in nitro-hydrochloric acid (_aqua regia_). 

([chi]. ) _Protoxide of Gold_ (Au^{2}O). --This oxide is a dark violetcolored powder which is converted by a temperature of 540° intometallic gold and oxygen. It is only soluble in aqua regia. Treatedwith hydrochloric acid, it yields the chloride of gold and the metal. With aqua ammonia, it yields the fulminating gold, which is a bluemass and very explosive. 

([chi]. ) _Peroxide of Gold_ (Au^{2}O^{3}). --This oxide is anolive-green or dark brown powder, containing variable quantities ofwater. Decomposed at 530°, it yields metallic gold and oxygen. 

_Reactions before the Blowpipe. _--Oxides of gold are reduced, in boththe oxidation and reduction flames, to the metal, which fuses tograins. 

_Borax_ does not dissolve it, but it is reduced to the metallic statein this flux in either flame. The reduced metal fuses upon charcoal toa grain. 

_Microcosmic Salt_ presents the same reactions as borax. 

When fused with soda, upon charcoal, the soda is absorbed, and thegold remains as a metallic grain. 

TENTH GROUP. --MOLYBDENUM, OSMIUM. 

These metals are not volatile, and are infusible before the blowpipe;but some of their oxides are volatile, and can be reduced to aninfusible metallic powder. 

(_a. _) _Molybdenum_ (Mo) occurs in the metallic state; also combinedwith sulphur, or as molybdic acid combined with lead. It is a white, brittle metal, and is unaltered by exposure to the air. When heateduntil it begins to glow, it is converted into a brown oxide. Heated ata continued dull red heat, it turns blue. At a higher temperature, itis oxidized to molybdic acid, when it glimmers and smokes, and isconverted into crystallized molybdic acid upon the surface. 

([chi]. ) _Protoxide of Molybdenum_ (MoO). --This oxide is a blackpowder. 

([chi]. ) _Deutoxide of Molybdenum_ (MoO^{2}). --This oxide is a darkcopper-colored crystalline powder. 

_Reactions before the Blowpipe. _--Metallic molybdenum, its protoxideand binoxide, are converted in the oxidation flame into molybdic acid. This acid fuses in the flame of oxidation to a brown liquid, whichspreads, volatilizes, and sublimes upon the charcoal as a yellowpowder, which appears crystalline in the vicinity of the assay. Thissublimate becomes white after cooling. Beyond this sublimate there isvisible a thin and not volatile ore of binoxide, after cooling; thisis of a dark copper-red color, and presenting a metallic lustre. 

Heated in a glass tube, closed at one end, it melts to a brown mass, vaporizes and sublimates to a white powder upon a cool portion of thetube. Immediately above the assay, yellow crystals are visible; thesecrystals are colorless after cooling, and the fused mass becomes lightyellow-colored and crystalline. 

Upon platinum foil, in the flame of oxidation, it melts and vaporizes, and becomes light yellow and crystalline after cooling. In thereduction flame it becomes blue, and brown-colored if the heat isincreased. 

Upon charcoal, in the reduction flame, it is absorbed by the charcoal;and, with an increase of the temperature, it is reduced to the metal, which remains as a grey powder after washing off the particles ofcharcoal. 

_Borax_ dissolves it, in the oxidation flame, upon platinum wireeasily, and in great quantity, to a clear yellow, which becomescolorless while cooling. By the addition of more of the molybdenicacid the bead is dark yellow, or red while hot, and opalescent whencold. In the reduction flame, the color of the bead is changed tobrown and transparent. By the addition of more of the acid, it becomesopaque. 

_Microcosmic Salt_ dissolves it in the oxidation flame, upon platinumwire, to a clear, yellowish-green bead, which becomes colorless aftercooling. In the reduction flame the bead is very dark and opaque, butbecomes of a bright green after cooling. This is the case likewiseupon charcoal. 

_Carbonate of Soda_ dissolves it upon platinum wire in the oxidationflame with intumescence, to a clear bead, which appears milk-whiteafter cooling. Upon charcoal the soda and the molybdic acid areabsorbed, the latter is reduced to the metallic state, the metalremaining as a grey powder after washing off the particles ofcharcoal. When molybdic acid, or any other oxide of this metal, isexposed upon platinum wire, or with platinum tongs, to the point ofthe blue flame, a yellowish-green color is communicated to theexternal flame. If also any of the compounds of molybdenum are mixedin the form of a powder with concentrated sulphuric acid and alcohol, and the latter inflamed, the flame of the alcohol appears coloredgreen. 

(_c. _) _Osmium_ (Os). --This metal occurs associated with platinum. Itis of a bluish-grey color, and is very brittle. Ignited in the openair, it is oxidized to volatile osmic acid, which is possessed of apungent smell, and affects the eyes. It communicates a bright whitecolor to the flame of alcohol. Osmium oxide (OsO^{2}) is converted inthe oxidation flame to osmic acid, which is volatilized with apeculiar smell, leaving a sublimate. 

In the reduction flame it is reduced to a dark-brown infusiblemetallic powder. It produces no reactions with fluxes. Carbonate ofsoda reduces it upon charcoal to an infusible metallic powder, whichappears, after washing off the particles of charcoal, of a dark-browncolor. 

ELEVENTH GROUP. --PLATINUM, PALLADIUM, IRIDIUM, RHODIUM, RUTHENIUM. 

These metals are infusible before the blowpipe. They are not volatile, nor are they oxidizable. Their oxides are, in both flames, reduced toa metallic and infusible powder. They give no reactions with fluxes, but are separated in the metallic form. These metals are generallyfound associated together in the native platinum, also with traces ofcopper, lead, and iron. 

The metal palladium is found native, associated with iridium andplatinum. This metal generally occurs in greatest quantity in Brazil. 

The metal rhodium is found along with platinum, but in very smallquantities. 

Iridium occurs in nature associated with osmium, gold, and platinum, in the mines of Russia. Its great hardness has rendered it desirablefor the points of gold pens. In South America this metal is foundnative, associated with platinum and osmium. The latter metal, associated with platinum and iridium, has been found in South America. 

As these metals will not oxidize or dissolve, they cannot be separatedfrom each other by the blowpipe with the reagents peculiar to thatspecies of analysis. It is true that colors may be discerned in thebeads, but these tints proceed from the presence of small traces ofcopper, iron, etc. 

The ore of osmium and iridium can be decomposed, and the formerrecognized by its fetid odor. This metal, strongly ignited in a glasstube with nitrate of potash, is converted to the oxide of osmium, which gives an odor not unlike the chloride of sulphur. 

As the metals of this group are very rare ones, especially the lastfour ones, we shall not devote an especial division to each of them. For a more detailed statement of their reactions, the student isreferred to the large works upon blowpipe analysis. 

CLASS III. 

NON-METALLIC SUBSTANCES. 

1. _Water_--2. _Nitric Acid_--3. _Carbon_--4. _Phosphorus_--5. _Sulphur_--6. _Boron_--7. _Silicon_--8. _Chlorine_--9. _Bromine_--10. _Iodine_--11. _Fluorine_--12. _Cyanogen_--13. _Selenium_. 

(1. ) _Water_ (HO). --Pure distilled water is composed of one volume ofoxygen, and two volumes of hydrogen gases; or, by weight, of one partof hydrogen to eight parts of oxygen gases. Water is never found purein nature, but possessing great solvent properties, it always is foundwith variable proportions of those substances it is most liable tomeet with, dissolved in it. Thus it derives various designationsdepending upon the nature of the substance it may hold in solution, aslime-water, etc. 

In taking cognizance of water in relation to blowpipe analysis, weregard it only as existing in minerals. The examination for water isgenerally performed thus: the substance may be placed in a dry tube, and then submitted to heat over a spirit-lamp. If the water exists inthe mineral mechanically it will soon be driven off, but if it existschemically combined, the heat will fail to drive it off, or if itdoes, it will only partially effect it. The water will condense uponthe cool portions of the tube, where it can be readily discerned. Ifthe water exists chemically combined, a much stronger heat must beapplied in order to separate it. 

Many substances may be perhaps mistaken for water by the beginner, such as the volatile acids, etc. 

(2. ) _Nitric Acid_ (NO^{5}). --Nitric acid occurs in nature in potashand soda saltpetre. These salts are generally impure, containing lime, as the sulphate, carbonate and nitrate, and also iron in smallquantity. The soda saltpetre generally contains a quantity of thechloride of sodium. The salts containing nitric acid deflagrate whenheated on charcoal. Substances containing nitric acid may be heated ina glass tube closed at one end, by which the characteristic red fumesof nitrous acid are eliminated. If the acid be in too minute aquantity to be thus distinguished, a portion of the substance may beintimately mixed with some bisulphate of potash, and treated as above. The sulphuric acid of the bisulphate combines with the base, andliberates the nitric acid, while the tube contains the nitrous acidgas. 

The nitrate of potassa, when heated in a glass tube, fuses to a clearglass, but gives off no water. When fused on platinum wire, itcommunicates to the external flame the characteristic violet color. When fused and ignited on charcoal, its surface becomes frothy, indicating the nitric acid. 

(3. ) _Carbon_ (C). --Carbon is found in nature in the pure crystallizedstate as the diamond. It occurs likewise in several allotropic statesas graphite, plumbago, charcoal, anthracite, etc. It exists in largequantities combined with oxygen as carbonic acid. 

The diamond, although combustible, requires too high a heat for itscombustion to enable us to burn it with the blowpipe. When excludedfrom the air, it may be heated to whiteness without undergoing fusion, but with the free access of air it burns at a temperature of 703° C, and is converted into carbonic acid. If mixed with nitre, the potassaretains the carbonic acid, and the carbon may be thus easilyestimated. If a mineral containing carbonic acid is heated, the gasescapes with effervescence, or a strong mineral acid as thehydrochloric will expel the acid with the characteristiceffervescence. 

(4. ) _Phosphorus, Phosphoric Acid _(PO^{6}). --This acid occurs in avariety of minerals, associated with yttria, copper, uranium, iron, lead, manganese, etc. Phosphoric acid may be detected in minerals bypursuing the following process: dip a small piece of the mineral insulphuric acid, and place it in the platinum tongs: this is heated atthe point of the blue flame, when the outer flame will become coloredof a greenish-blue hue. This color will not be mistaken for those ofboracic acid, copper, or baryta. Some of the phosphoric minerals, whenheated in the inner flame, will color the outer flame green. 

If alumina be present with the phosphoric acid, the following wetmethod should be adopted for the detection of the latter: thesubstance should be powdered in the agate mortar with a mixture of sixparts of soda, and one and a half parts of silica. The entire massshould now be placed on charcoal, and melted in the flame ofoxidation. The residue should be treated with boiling water, whichdissolves the phosphate and the excess of carbonate of soda, while thesilicate of alumina, with some of the soda, is left. The clear liquoris now treated with acetic acid, and heated over the spirit-lamp, anda small portion of crystallized nitrate of silver added; alemon-yellow precipitate of phosphate of silver is quickly developed. Previous to the addition of the nitrate, the liquor should be wellheated; otherwise, a white precipitate of dipyrophosphate of silverwill be produced. 

If the examination be of any of the metallic phosphides, thesubstances should be powdered in the agate mortar, and fused withnitrate of potassa on the platinum wire; the fused mass should betreated with soda in the same manner as any substance containingphosphoric acid. The metal and the phosphorus are oxidized, while thephosphate of potassa is fused, and the metallic oxide separates. 

(5. ) _Sulphur_ (S). --Sulphur is found native in crystals It isfrequently found associated with lime, iron, silica, carbon, etc. , andcombined extensively with metals. 

The principal acid of sulphur (the sulphuric, SO^{3}) occurs combinedwith the earths, the alkalies, and the metallic oxides. Native sulphuris recognized, when heated upon charcoal, by its odor (sulphurousacid) and the blue color of its flame. The compounds of sulphur may bedetected by several methods. If the substance is heated in a glasstube, closed at one end, the yellow sublimate of sulphur will subsideupon the cool portions of the tube; if the substance should alsocontain arsenic, the sublimate will present itself as a light brownincrustation, consisting of the sulphide of arsenic. 

If the assay is heated in the open glass tube, sulphurous acid willthus be generated; but, if the gas is too little to be detected by thesmell, a strip of moistened litmus paper will indicate the presence ofthe acid. 

The assay will give off sulphurous fumes if heated in the flame ofoxidation. 

If the powdered substance is fused with two parts of soda, and onepart of borax, upon charcoal, the sulphide of sodium is formed. Thissalt, if moistened and applied to a polished silver surface, willblacken it. The borax serves no other purpose than to prevent theabsorption of the formed sulphide of sodium by the charcoal. Asselenium will blacken silver in the manner above indicated, thepresence of this substance should be first ascertained, by heating theassay; when, if it be present, the characteristic horse-radish odorwill reveal the fact. 

Sulphuric acid may be detected by fusing the substance with two partsof soda, and one part of borax, on charcoal, in the flame ofreduction; the mass must now be wetted with water, and placed incontact with a surface of bright silver; when, if sulphuric acid bepresent, the silver will become blackened. 

Or the substance may be fused with silicate of soda in the flame ofreduction. In this case, the soda combines with a portion of thesulphuric acid, which is then reduced to the sulphide, while the beadbecomes of an orange or red color, depending upon the amount of thesulphuric acid present. If the assay should, however, be colored, thenthe previous treatment should be resorted to. 

(6. ) _Boron, Boracic Acid_ (BO^{3}). --This acid occurs in nature inseveral minerals combined with various bases, such as magnesia, lime, soda, alumina, etc. Combined with water, this acid exists in nature asthe native boracic acid; this acid gives with test paper prepared fromBrazil wood, when moistened with water, a characteristic reaction, forthe paper becomes completely bleached. An alcohol solution turnscurcuma test paper brown. Heated on charcoal, it fuses to a clearbead; but, if the sulphate of lime be present, the bead becomes opaqueupon cooling. 

The following reaction is a certain one: the substance is pulverizedand mixed with a flux of four and a half parts of bisulphate ofpotassa, and one part of pulverized fluoride of calcium. The whole ismade into a paste with water, and the assay is placed on the platinumwire, and submitted to the point of the blue flame. While the assay ismelting, fluoboric gas is disengaged, which tinges the outer flamegreen. If but a small portion of boracic acid is present, the colorwill be quite evanescent. 

(7. ) _Silica, Silicic Acid_ (SiO^{3}). --This acid exists in thegreatest plenty, forming no inconsiderable portion of the solid partof this earth. It exists nearly pure in crystallized quartz, chalcedony, cornelian, flint, etc. , the coloring ingredients of theseminerals being generally iron or manganese. 

With _microcosmic salt_, silica forms a bead in the flame of oxidationwhich, while hot, is clear, while the separated silica floats in it. Aplatinum wire is generally used for the purpose, the end of it beingfirst dipped in the salt which is fused into a bead, after which thesilica must be added, and then the bead submitted to the flame ofoxidation. 

The silicates dissolve in soda but partially, and then witheffervescence. If the oxygen of the acid be twice that of the base, aclear bead will be obtained that will retain its transparency whencold. If the soda be added in small quantity, the bead will then beopaque. In the first instance, a part of the base which separates isre-dissolved, and, therefore, the transparency of the glass; but, iftoo large a quantity of the soda is added, the separation of the baseis sufficient to render the assay infusible. 

(8. ) _Chlorine_ (Cl). --Chlorine exists in nature always incombination, as the chlorides of sodium, potassium, calcium, ammonium, magnesia, silver, mercury, lead, copper, etc. 

The chlorine existing in metallic chlorides may be detected asfollows: the wet way may be accomplished in the following manner. Ifthe substance is insoluble, it must be melted with soda to render itsoluble; if it be already soluble it must be dissolved in pure water, and nitrate of silver added, when the one ten-thousandth part ofchlorine will manifest its presence by imparting a milky hue to thefluid. 

By the blowpipe, chlorine may be detected in the following manner:Oxide of copper is dissolved in microcosmic salt on the platinum wirein the flame of oxidation, and a clear bead is obtained. The substancecontaining the chlorine is now added, and heat is applied. The assaywill soon be enveloped by a blue or purplish flame. As none of theacids that occur in the mineral kingdom give this reaction, chlorinecannot be confounded with them, for those which impart a color to theflame, when mixed with a copper salt, will not do so when tested inthe microcosmic salt bead as above indicated. 

If the assay is soluble in water, the following method may befollowed: a small quantity of sulphate of copper or iron is dissolved;a few drops of the solution is placed upon a bright surface of silver, and the metallic chloride added; when, if chlorine is present, thesilver is blackened. If the chloride is insoluble in water, it must berendered soluble by fusion upon a platinum wire with soda, and thentreated as above. [2]

 [2] Plattner. 

(9. ) _Bromine_ (Br). --The bromide of magnesium and sodium exists inmany salt springs, and it is from these that the bromine of commerceis obtained. The metallic bromides give the same reactions on silverwith the microcosmic bead and copper salt as the metallic chlorides. The purplish color which, however, characterizes the chlorides, ismore inclined to greenish with the bromides. If the substance beplaced in a flask or glass tube, and fused with bisulphate of potassa, over the spirit-lamp, sulphurous gas and bromine will be eliminated. Bromine will be readily detected by its yellow color and its smell. Bromine may be readily detected by passing a current of chlorinethrough the fluid, after which ether is added and the whole isagitated. The ether rises to the top, carrying with it the bromine insolution; after being withdrawn, this ether is mixed with potassa, bywhich the bromide and bromate of potassa are formed. The solution isevaporated to dryness, the residue is fused in a platinum vessel, thebromate is decomposed, while the bromide remains; this must bedistilled with sulphuric acid and the binoxide of manganese. A red orbrown vapor will then appear, indicating the presence of bromine; thisvapor will color starch paste--which may be put in the receiver onpurpose--of a deep orange color. 

If, to a solution containing a bromide, concentrated sulphuric ornitric acid be added, the bromine is liberated and colors the solutionyellow or red. The hypochlorites act in the same manner. The brominesalts are coming into use extensively in photography, in consequenceof their greater sensitiveness to the action of light than thechlorides alone. 

(10. ) _Iodine_ (I). --This element occurs in salt-springs, generallycombined with sodium; it also exists in rock-salt; it has likewisebeen found in sea-water, also in a mineral from Mexico, in combinationwith silver, and in one from Silesia, in combination with zinc. Assea-water contains iodine, we would consequently expect to find itexisting in the sea-weeds, and it is generally from the ashes of thesethat it is obtained in commerce. 

When the metallic iodides are fused with the microcosmic salt andcopper, as previously indicated, they impart a green color to theflame. This color cannot be mistaken for the color imparted to theflame by copper alone. When the metallic iodides are fused in a glasstube, closed at one end, with the bisulphate of potassa, the vapor ofiodine is liberated, and may be recognized by its characteristiccolor. Those mineral waters containing iodine can be treated the sameas for bromine, as previously indicated, while the violet-coloredvapor of the iodine can be easily discerned. The nitrate of silver isthe best test for iodine, the yellow color of the iodide of silverbeing not easily mistaken, while its almost insolubility in ammoniawill confirm its identity. The chloride of silver, on the contrary, dissolves in ammonia with the greatest facility. 

The reactions of iodine are similar to those of bromine withconcentrated sulphuric acid and binoxide of manganese, and with nitricacid: The iodine is released and, if the quantity be not too great, colors the liquid brown. If there be a considerable quantity of iodinepresent, it is precipitated as a dark colored powder. Either of these, when heated, gives out the violet-color of the iodine. 

With starch paste free iodine combines, producing a deep bluecompound. If, however, the iodine be in very minute quantity, thecolor, instead of being blue, will be light violet or rose color. 

If to a solution of the sulphate of copper, to which a small portionof sulphurous acid has been added, a liquid containing iodine andbromine is poured in, a dirty, white precipitate of the subiodide ofcopper is produced, and the bromine remains in the solution. Thelatter may then be tested for the bromine by strong sulphuric acid. 

(11. ) _Fluorine_ (Fl). --This element exists combined with sodium, calcium, lithium, aluminium, magnesium, yttrium, and cerium. Fluorinealso exists in the enamel of the teeth, and in the bones of someanimals. This element has a strong affinity for hydrogen, and, therefore, we find it frequently in the form of hydrofluoric acid. Brazil-wood paper is the most delicate test for hydrofluoric acid, which it tinges of a light yellow color. Phosphoric acid likewisecolors Brazil paper yellow, but as this acid is not volatile at a heatsufficient to examine hydrofluoric acid, there can be no mistake. Ifthe substance is supposed to contain this acid, it should be placed ona slip of glass, and moistened with hydrochloric acid, when the testpaper may be applied, and the characteristic yellow color willindicate the presence of the fluorine. 

As hydrofluoric acid acts upon glass, this property may be used forits detection. The substance may be put into a glass tube, andsulphuric acid poured upon it in sufficient quantity to moisten it; aslight heat applied to the tube will develop the acid, which will actupon the glass of the tube. If the acid is retained in the mineral bya feeble affinity, and water be present, a piece of it may be put inthe tube and heated, when the acid gas will be eliminated. The testpaper will indicate its presence, even before it has time to act uponthe glass. If the temperature be too high, fluosilicic acid isgenerated, and will form a silicious incrustation upon the coolportion of the tube. 

If the fluorine is too minute to produce either of the abovereactions, then the following process, recommended by Plattner, shouldbe followed: the assay should be mixed with metaphosphate of soda, formed by heating the microcosmic salt to dull redness. The mass mustthen be placed in an open glass tube, in such a position that therewill be an access of hot air from the flame. Thus aqueous hydrofluoricacid is formed, which can be recognized by its smell being moresuffocating than chlorine, and also by the etching produced by thecondensation of vapor in the tube. Moist Brazil paper, applied to theextremity of the tube, will be instantly colored yellow. 

Merlet's method for the detection of this acid is the following:[3]Pulverize the substance for examination, then triturate it to animpalpable powder, and mix it with an equal part of bisulphate ofpotassa. Heat the mass gradually in a moderately wide test-tube. Thejudicious application of heat must be strictly observed, for if theoperator first heats the part of the tube where the assay rests, thewhole may be lost on account of the glass being shattered. Thespirit-flame must be first applied to the fore part of the tube, andthen made to recede slowly until it fuses the assay. After the mixturehas been for some time kept in a molten state, the lamp must bewithdrawn, and the part containing the assay severed with a file. Thefore part of the tube must then be well washed, and afterwards driedwith bibulous paper. Should the fluorine contained in the substance beappreciable, the glass tube, when held up to the light, will be foundto have lost its transparency, and to be very rough to the touch. 

 [3] Quoted by Plattner. 

Great care should be observed not to allow this very corrosive acid tocome into contact with the skin, as an ulcer will be the consequencethat will be extremely difficult to heal. 

When hydrofluoric acid comes in contact with any silicious substance, hydrofluosilicic acid gas is always formed. 

(12. ) _Selenium_ (Se). --This element occurs in combination with leadas the selenide, and with copper as the selenide of copper. It existsalso combined with cobalt and lead, as the selenide of these metals;also as the selenide of lead and mercury. 

The smallest trace of selenium may be detected by igniting a smallpiece of charcoal in the flame of oxidation, when the peculiar andunmistakable odor of decayed horse-radish will indicate the presenceof that element. An orange vapor is eliminated if the selenium bepresent in any quantity, while there is an incrustation around theassay of a grey color, with a metallic lustre. This incrustationfrequently presents a reddish-violet color at its exterior edges, often running into a deep blue. If a substance containing selenium beplaced in a glass tube, closed at one end, and submitted to heat, theselenium is sublimed, with an orange-colored vapor, and with thecharacteristic odor of that substance. Upon the cool portions of thetube a steel-grey sublimate is deposited, and, beyond that, can bediscerned small crystals of selenic acid. If the mineral be theseleniferous lead glance, sulphurous acid gas will be given off, andmay be detected by the smell, or by a strip of moistened litmus paper. 

If arsenic is present, heating upon charcoal will quickly lead to thedetermination of the one from the other. 

 * * * * *

TABULAR STATEMENT OF THE REACTIONS OF MINERALS BEFORE THE BLOWPIPE. 

In PART THIRD of this work, commencing at page 109, the student willfind a sufficiently explicit description of the blowpipe reactions ofthose principal substances that would be likely to come beneath hisattention. The following tabular statement of those reactions--whichwe take from Scheerer and Blanford's excellent little work upon theblowpipe--will be of great benefit, as a vehicle for consultation, when the want of time--or during the hurry of an examination--precludesthe attentive perusal of the more lengthy descriptions in the text. 

In the examination of minerals, before the student avails himself ofthe aid of the blowpipe, he should not neglect to examine the specimenrigidly in relation to its physical characters, such as its hardness, lustre, color, and peculiar crystallization. It is where thedifference of two minerals cannot be distinguished by their physicalappearance, that the aid of the blowpipe comes in most significantlyas an auxiliary. For instance, the two minerals molybdenite andgraphite resemble each other very closely, when examined in regard totheir physical appearance, but the blowpipe will quickly discriminatethem, for if a small piece of the former mineral be placed in theflame of oxidation, a bright green color will be communicated to theflame beyond it, while in the latter there will be no color. Thus, ina very short time, these two minerals can be distinguished from eachother by aid of the blowpipe, while no amount of physical examinationcould determine that point. The blowpipe is equally an indispensableinstrument in the determination of certain minerals which may exist inothers as essential or non-essential constituents of them. Forinstance, should a minute quantity of manganese be present in amineral, it must be fused with twice its bulk of a mixture of twoparts of carbonate of soda, and one part of the nitrate of potassa, inthe flame of oxidation upon platinum foil. The manganate of soda thusformed will color the fused mass of a bluish-green tint. 

Or a slight quantity of arsenic may be discerned by the followingprocess recommended by Plattner:[4] one grain of the finely pulverizedmetal is mixed with six grains of citrate of potassa, and slowlyheated on the platinum spoon. By this means the metals are oxidized, while the arseniate of potassa is obtained. Then boil the fused massin a small quantity of water in a porcelain vessel till all thoarseniate is dissolved. The metallic oxides are allowed to subside, and the above solution decanted off into another porcelain vessel. Afew drops of sulphuric acid are added, and the solution boiled toexpel the nitric acid, after which it is evaporated to dryness. Inthis operation, the sulphuric acid should be added only in sufficientquantity to drive off the nitric acid, or, at the utmost, to form abisulphate with the excess of potassa. When dry, the salt thusobtained is pulverized in an agate mortar, and mixed with about threetimes its volume of oxalate of potassa, and a little charcoal powder. The mixture is introduced into a glass bulb having a narrow neck, andgently warmed over a spirit-lamp in order to drive off the moisture, which must be absorbed by a piece of blotting-paper in the neck of thebulb. After a short time, the temperature is increased to a low redheat, at which the arsenious acid is reduced and the metallic arsenicsublimed, and which re-condenses in the neck of the bulb. If therethe arsenic be so small in quantity as to exhibit no metallic lustre, the neck of the bulb may be cut off with a file immediately above thesublimate, and the latter exposed to the flame of the blowpipe, whenthe arsenic is volatilized, and may be recognized by its garlic odor. 

 [4] Quoted by Scheerer. 

If the presence of cadmium is suspected in zinc-blende, it may bedetected by fusing a small piece of the blende upon charcoal incarbonate of soda. The peculiar bright yellow sublimate of the oxideof cadmium, if it be present, will not fail to indicate it. Thisincrustation can be easily distinguished from that of zinc. Thus, withthe three illustrations we have given, the student will readilycomprehend the great utility of the blowpipe in the examination ofminerals. 

Although the following tables were not arranged especially for thelast part of this work, still this arrangement is so good that bytheir consultation the student will readily comprehend at a glancewhat requires some detail to explain, and we feel no hesitation insaying that, although they are not very copious, they will not fail toimpart a vast amount of information, if consulted with any degree ofcarefulness. 

The minerals given are such as are best known to English and Americanmineralogists under the names specified. For more detailed reactionsthan could be crowded into a table, the student will have to consultthe particular substance as treated in Part Third. If this part isperused carefully previous to consulting the tables, these will befound eminently serviceable as a refresher of the memory, and may thussave much time and trouble. 

And, finally, we would certainly recommend the student, after he shallhave gone through our little volume (if he is ambitious of makinghimself a thorough blowpipe analyst), to then take up the larger worksof Berzelius and Plattner, for our treatise pretends to nothing morethan a humble introduction to these more copious and scientific works. 

 * * * * *

Mineral. Diamond

Formula. C

Behavior

 in glass-bulb. --

 on platinum foil. In fine powder is slowly consumed without residue in a strong oxidizing Flame. 

 * * * * *

Mineral. Graphite

Formula. C with some iron silica, etc. 

Behavior

 in glass-bulb. Generally gives off water. 

 on platinum foil. Is slowly consumed leaving more or less ash, principally Fe^{2}O^{3}. 

 * * * * *

Mineral. Anthracite

Formula. C + x[. H]

Behavior

 in glass-bulb. Evolves water. 

 on platinum foil. Is slowly consumed with the exception of a small quantity of ash. 

 * * * * *

Mineral. Wallsend-coal

Formula. C, H, O, S and ash. 

Behavior

 in glass-bulb. Intumesces and gives off water and tarry matters which partly condense in bulb, and leave a porous coke. 

 on platinum foil. Takes fire under blowpipe flame, and burns with a smoky flame, depositing much soot and leaving a porous cinder which burns slowly and leaves a small ash. 

 * * * * *

Mineral. Cannel-coal

Formula. C, H, N, O, S and ash. 

Behavior

 in glass-bulb. As the preceding but gives off more tar. 

 on platinum foil. Similar to the preceding. If held to the lamp-flame, takes fire and burns for some seconds. 

 * * * * *

Mineral. Brown-coal

Formula. C, H, N, O, S, and ash. 

Behavior

 in glass-bulb. Gives off much water and tar, and leaves a porous cinder retaining the form of the original fragment. 

 on platinum foil. Burns slowly and without flame, leaving some ash. 

 * * * * *

Mineral. Asphaltum

Formula. C + H + O. 

Behavior

 in glass-bulb. Fuses with ease affording an empyreumatic oil having an alkaline reaction, and combustible gasses, and leaves a carbonaceous residue, which is entirely consumed under the blowpipe flame, except a little ash. 

 on platinum foil. Takes fire and burns with a bright flame and a thick smoke. 

 * * * * *

Mineral. Elaterite

Formula. C + H. 

Behavior

 in glass-bulb. Fuses and gives off water having an acid reaction, naphtha and a tarry fluid, which chiefly condense in the neck of the bulb, and leave a light, pulverulent carbonaceous residue. 

 on platinum foil. Fuses, takes fire, and burns with a smoky flame, leaving a carbonaceous residue, which under the blowpipe flame, is quickly consumed, with the exception of the ashes. 

 * * * * *

Mineral. Hachettine

Formula. C + H. 

Behavior

 in glass-bulb. Fuses to a clear colorless liquid, which solidifies on cooling and has a tallow-like smell. 

 on platinum foil. Fuses, takes fire, and burns with a bright flame until entirely consumed. 

 * * * * *

Mineral. Ozokerite

Formula. C + H. 

Behavior

 in glass-bulb. Fuses readily to a clear brown oily fluid, which solidifies on cooling. 

 on platinum foil. As the preceding. 

 * * * * *

Mineral. Amber

Formula. C + H + O. 

Behavior

 in glass-bulb. Fuses with difficulty, and affords water, an empyreumatic oil, and succinic acid which condense in the neck of the bulb leaving a shining black residue. 

 on platinum foil. Takes fire and burns with a yellow flame and a peculiar aromatic odor. 

 * * * * *

Mineral. Mellite

Formula. [. .. Al][=M]^{3} + 15[. H]

Behavior

 in glass-bulb. Gives off water. If heated to redness, is carbonized, and gives a slight empyreumatic odor. 

 on platinum foil. On charcoal burns to a white ash, which moistened with nitrate of cobalt and heated shows the alumina reaction. 

 * * * * *

 POTASH. 

 * * * * *

Mineral. Nitre

Formula. [. K][. .. .. N]

Behavior

 (1) in glass-bulb. Fuses readily to a clear liquid and with a strong heat boils with the evolution of oxygen. 

 (2) in open tube. --

 (3) on charcoal. Deflagrates leaving a saline mass, which is absorbed into charcoal and gives a sulphur reaction on silver. 

 (4) in forceps. On platinum wire fuses and colors the flame violet more or less modified by lime and soda. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. With bisulphate of potassa in the glass-bulb evolves nitrous fumes. 

 * * * * *

Mineral. Polyhalite

Formula. [. K][. .. S]+[. Mg][. .. S]+2[. Ca][. .. S]+2[. H]

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. Fuses to a reddish bead, which in the reducing flame solidifies and shrinks to a hollow crust. 

 (4) in forceps. On platinum wire fuses and colors the flame yellow from a small quantity of soda. 

 (5) in borax. Dissolves with ebullition to a clear glass, which is slightly colored by iron, and when saturated become opaque on cooling. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses. The alkalies are absorbed by the charcoal leaving the lime and magnesia infusible on the surface. 

 (8) Special reactions. The alkaline mass when laid on silver gives a sulphur reaction. 

 * * * * *

 SODA. 

 * * * * *

Mineral. Rock-salt

Formula. NaCl. 

Behavior

 (1) in glass-bulb. Fuses to a clear liquid

 (2) in open tube. --

 (3) on charcoal. Fuses, is absorbed by the charcoal and partially volatilized incrusting the charcoal around. 

 (4) in forceps. Fuses with great ease and colors the flame yellow. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. Gives the chlorine reactions. 

 * * * * *

Mineral. Natron

Formula. [. Na][. . C] + 10[. H]

Behavior

 (1) in glass-bulb. Fuses, with the evolution of water. 

 (2) in open tube. --

 (3) on charcoal. Fuses, and is absorbed into the pores of the charcoal. 

 (4) in forceps. Fuses and behaves as the preceding. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. Dissolves in acid with violent effervescence. 

 * * * * *

Mineral. Soda-nitre

Formula. [. Na][. .. .. N]. 

Behavior

 (1) in glass-bulb. Fuses and if strongly heated evolves nitrous fumes. (2) in open tube. -- (3) on charcoal. Deflagrates and is absorbed into the charcoal. 

 (4) in forceps. Deflagrates on platinum wire, coloring the flame yellow. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. In a glass-bulb with bisulphate of potassa, gives the NO^{5}-reaction. 

 * * * * *

Mineral. Glauber-salt

Formula. [. Na][. .. S] + 10[. H]. 

Behavior

 (1) in glass-bulb. Fuses and gives off water having a neutral reaction. 

 (2) in open tube. --

 (3) on charcoal. Fuses, and is absorbed by the charcoal. The saturated charcoal laid upon silver gives the sulphur reaction

 (4) in forceps. Fuses and colors the flame yellow. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. Gives the SO^{3}-reaction. 

 * * * * *

Mineral. Glauberite

Formula. [. Na][. .. S] + [. Ca][. .. S]. 

Behavior

 (1) in glass-bulb. Decrepitates with the evolution of more or less water, and when strongly heated fuses to a clear liquid. 

 (2) in open tube. --

 (3) on charcoal. Fuses to a clear bead, then spreads out; the soda is absorbed and the lime left on the surface. Laid on silver, the fused mass gives a sulphur reaction. 

 (4) in forceps. Fuses easily to a clear glass, coloring the flame yellow. 

 (5) in borax. Fuses easily and gives the lime reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone in charcoal. 

 (8) Special reactions. As in preceding. 

 * * * * *

Mineral. Borax

Formula. [. Na][. .. B]^{2}+10[. H]. 

Behavior

 (1) in glass-bulb. Intumesces with the evolution of water, and under a strong heat fuses. 

 (2) in open tube. --

 (3) on charcoal. Intumesces and fuses to a clear bead more or less colored by impurities. 

 (4) in forceps. As on charcoal. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. Fuses to a clear bead, which becomes crystalline on cooling. 

 (8) Special reactions. Gives the boracic-acid-reaction. 

 * * * * *

Mineral. Cryolite

Formula. 3NaFl+Al^{2}Fl^{3}. 

Behavior

 (1) in glass-bulb. Decrepitates slightly and gives a trace of water. 

 (2) in open tube. If heated so that the flame be allowed to play up the tube upon the mineral, flourine is evolved, which corrodes the interior of the tube. 

 (3) on charcoal. Fuses to a limpid bead, which on cooling becomes a white enamel. If heated for some time, it bubbles, gives off fluorine and becomes infusible. 

 (4) in forceps. Fuses, coloring the flame yellow. 

 (5) in borax. Dissolves to a clear bead, which is rendered opaque by a large addition. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a clear bead, then spreads out on the charcoal, the soda is absorbed, and an infusible mass of alumina remains. 

 (8) Special reactions. If the alumina residue obtained be moistened with cobalt solution and heated strongly, it assumes a beautiful blue color. 

 * * * * *

 BARYTA AND STRONTIA. 

 * * * * *

Mineral. Heavy-spar

Formula. [. Ba][. .. S]. 

Behavior

 (1) in glass-bulb. Sometimes decrepitates and gives off more or less water

 (2) in open tube. --

 (3) on charcoal. Fuses in the reducing flame. 

 (4) in forceps. Fuses with difficulty on edges. Colors the outer flame green. In reducing flame forms BaS, which fuses readily. 

 (5) in borax. Gives the baryta-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a clear bead; then spreads out and is absorbed into the charcoal. The fused mass laid on silver gives the S-reaction. 

 (8) Special reactions. If fused with potassa on platinum, gives the SO^{3}-reaction. 

 * * * * *

Mineral. Celestine

Formula. [. Sr][. .. S]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. Fuses to a milk-white bead. 

 (4) in forceps. Colors the flame crimson. 

 (5) in borax. Gives the strontia-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Similar to the preceding. 

 (8) Special reactions. Similar to the preceding. 

 * * * * *

Mineral. Witherite

Formula. [. Ba][. . C]. 

Behavior

 (1) in glass-bulb. Decrepitates more or less and evolves Water. 

 (2) in open tube. --

 (3) on charcoal. Fuses, effervesces, and is partially absorbed by the charcoal. 

 (4) in forceps. Colors the outer flame intensely green. 

 (5) in borax. Dissolves with effervescence and gives the baryta-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a clear bead; then spreads out and passes into the charcoal. 

 (8) Special reactions. In dilute HCl dissolves with much effervescence. 

 * * * * *

Mineral. Strontianite

Formula. [. Sr][. . C]. 

Behavior

 (1) in glass-bulb. Becomes opaque. 

 (2) in open tube. --

 (3) on charcoal. As in the forceps. 

 (4) in forceps. Exfoliates and becomes arborescent. The filaments glow brilliantly and fuse on the point. Colors the flame brilliantly crimson. 

 (5) in borax. Resembles the preceding. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. As the preceding. 

 * * * * *

Mineral. Barytocalcite. 

Formula. [. Ba][. . C] + [. Ca][. . C]. 

Behavior

 (1) in glass-bulb. As in the preceding. 

 (2) in open tube. --

 (3) on charcoal. In powder frits together, but does not fuse. 

 (4) in forceps. Colors the flame green in the centre and red towards the point. 

 (5) in borax. Dissolves with effervescence. In large quantities gives a semi-crystalline bead. 

 (6) in mic. Salt. As in borax, but the saturated bead is milk-white. 

 (7) with carb. Soda. Fuses, and is partially absorbed leaving the lime on the surface. 

 (8) Special reactions. As witherite. 

 * * * * *

 LIME. 

 * * * * *

Mineral. Gypsum

Formula. [. Ca][. .. S] + 2[. H]. 

Behavior

 (1) in glass-bulb. Turns white, giving off water and being converted into plaster of Paris. 

 (2) in open tube. --

 (3) on charcoal. In the reducing flame forms CaS, which has an alkaline reaction on test paper, and gives a sulphur-reaction when laid on silver and moistened. 

 (4) in forceps. Fuses with difficulty to a bead, coloring the flame red. 

 (5) in borax. Dissolves to a clear bead, which gives the lime- reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Behaves as lime. The alkaline mass laid on silver and moistened gives the sulphur-reaction. 

 (8) Special reactions. Gives the sulphuric-acid reaction. 

 * * * * *

Mineral. Apatite { ClFormula. [. Ca]{ -- +3[. Ca]^{3}[. .. .. P] { FlBehavior

 (1) in glass-bulb. Occasionally decrepitates and gives off some water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. IV. Previously dipped in SO^{3} colors the flame green, afterwards red. 

 (5) in borax. Dissolves easily and when in some quantity gives an opaline bead. 

 (6) in mic. Salt. Gives the lime-reaction. 

 (7) with carb. Soda. Is infusible. The alkali is absorbed, leaving the lime on the on the surface of the charcoal. 

 (8) Special reactions. With microcosmic salt and oxide of copper, gives the chlorine-reaction. With microcosmic salt in the open tube evolves fluorine. 

 * * * * *

Mineral. Pharmacolite

Formula. [. Ca]^{2}[. .. .. As] + 6[. H]. 

Behavior

 (1) in glass-bulb. Gives off water, and emits an arsenical odor. 

 (2) in open tube. --

 (3) on charcoal. Fuses to an opaque bead and emits a strong smell of arsenic. 

 (4) in forceps. Fuses to a translucent violet colored bead, the color being due to cobalt. Colors the flame blue at first, then faintly red. 

 (5) in borax. Dissolves readily to a bead strongly colored by cobalt, which obscures the lime-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses, and emits As. The alkali is then absorbed by the charcoal, as in the preceding. 

 (8) Special reactions. --

 * * * * *

Mineral. Calespar

Formula. [. Ca][. . C]. 

Behavior

 (1) in glass-bulb. Turns white and sometimes decrepitates. Strongly heated loses CO^{2} and becomes caustic. 

 (2) in open tube. --

 (3) on charcoal. Turns white, or brown if containing much iron or manganese and glows brilliantly. 

 (4) in forceps. Glows brilliantly, coloring the flame red. Becomes caustic and shows a strong alkaline reaction. 

 (5) in borax. Dissolves with evolution of CO^{2} and when pure gives the lime-reaction. The bead is generally more or less colored by iron and manganese. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses, and behaves as other lime-salts. 

 (8) Special reactions. Dissolves with effervescence in cold HCl. 

 * * * * *

Mineral. Fluorspar

Formula. CaFl

Behavior

 (1) in glass-bulb. Phosphoresces with various colors, when heated in the dark. 

 (2) in open tube. --

 (3) on charcoal. Fuses easily to a clear bead, which becomes opaque on cooling, then loses fluorine, glows brilliantly and becomes infusible. 

 (4) in forceps. As on charcoal. Colors the flame red. 

 (5) in borax. Gives the lime-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a clear bead, opaque on cooling. With an addition of the alkali behaves as lime. 

 (8) Special reactions. With microcosmic salt in open tube gives the fluorine-reaction. 

 * * * * *

 MAGNESIA. 

 * * * * *

Mineral. Brucite

Formula. [. Mg][. H]. 

Behavior

 (1) in glass-bulb. Evolves water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. 

 (5) in borax. Behaves as magnesia. Sometimes gives a faint iron-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Behaves as magnesia. 

 (8) Special reactions. With nitrate of cobalt, gives the magnesia reaction

 * * * * *

Mineral. Epsomite

Formula. [. Mg][. .. S] + 7[. H]. 

Behavior

 (1) in glass-bulb. Evolves water having an acid reaction on test paper. 

 (2) in open tube. --

 (3) on charcoal. Gives of HO and SO^{3}, shines brilliantly, and becomes alkaline and caustic. 

 (4) in forceps. V. As on charcoal. 

 (5) in borax. Behaves as magnesia. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. The alkali is absorbed leaving the magnesia on surface of the charcoal. Gives the sulphur-reaction on silver. 

 (8) Special reactions. The magnesian residue obtained on treating with carbonate of soda (7), assumes a flesh-tint, when treated with cobalt. 

 * * * * *

Mineral. Boracite

Formula. [. Mg][. .. B]^{2} + 2[. Mg][. .. B]. 

Behavior

 (1) in glass-bulb. Occasionally gives off a trace of water. 

 (2) in open tube. --

 (3) on charcoal. Fuses with intumescence to a white crystalline bead. 

 (4) in forceps. I. As on charcoal. Colors the flame green. 

 (5) in borax. Fuses easily to a clear bead, which is crystalline, when containing much of the mineral, and is usually slightly tinted by iron. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. With a small quantity of alkali fuses to a clear bead on cooling. With a larger quantity gives a clear, uncrystallizable bead. 

 (8) Special reactions. --

 * * * * *

Mineral. Magnesite

Formula. [. Mg][. . C]. 

Behavior

 (1) in glass-bulb. Sometimes gives off a small quantity of water. 

 (2) in open tube. --

 (3) on charcoal. Is infusible. With cobalt-solution, assumes a dusky flesh tint. 

 (4) in forceps. --

 (5) in borax. Behaves as magnesia. Sometimes a slight iron-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a bead, the soda is then absorbed, leaving an infusable mass of magnesia. 

 (8) Special reactions. The magnesian residue obtained by fusing with carbonate of soda gives the magnesian-reaction with nitrate of cobalt. Dissolves with effervescence in warm HCl. 

 * * * * *

Mineral. Mesitine spar

Formula. ([. Mg][. Fe][. Mn])[. . C]. 

Behavior

 (1) in glass-bulb. As magnesite. 

 (2) in open tube. --

 (3) on charcoal. Is infusible. Assumes a deep brown color. 

 (4) in forceps. V. 

 (5) in borax. Gives the iron and manganese-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As magnesite, but the residual mass has a dark color from iron and manganese. 

 (8) Special reactions. Dissolves with effervescense in warm HCl. With carbonate of soda and nitre gives a manganese-reaction. 

 * * * * *

 ALUMINA. 

 * * * * *

Mineral. Sapphire Corundum Emery

Formula. [. .. Al=]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. 

 (5) in borax. In fine powder dissolves slowly to a colorless glass. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. In fine powder moistened with cobalt-solution and heated yields a blue color. 

 * * * * *

Mineral. Websterite

Formula. [. .. Al][. .. S] + 9[. H]. 

Behavior

 (1) in glass-bulb. Gives off water, and, when heated to incipient redness, sulphurous acid. 

 (2) in open tube. --

 (3) on charcoal. Gives off water and SO^{3}, leaving an infusible mass. 

 (4) in forceps. V. 

 (5) in borax. Behaves as alumina. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Yields an infusible mass, which laid on silver and moistened, produces a black stain. 

 (8) Special reactions. Fused with potassa in platinum has no action on silver. Cobalt-solution produces the alumina reaction. 

 * * * * *

Mineral. Native Alum

Formula. [. R][. .. S] + [. .. Al][. .. S]^{3} + 24[. H]. 

Behavior

 (1) in glass-bulb. Intumesces greatly and gives off much water. Strongly heated, evolves SO^{3}, which reddens litmus. 

 (2) in open tube. --

 (3) on charcoal. Intumesces and become infusible. 

 (4) in forceps. V. Colors the flame violet if a potassa alum--yellow if soda--be present. 

 (5) in borax. Dissolves and gives the iron and manganese reaction, if these oxides be present. Otherwise the bead is colorless. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. The alkali is absorbed into the charcoal, leaving an infusable mass which gives the sulfur reaction on silver. 

 (8) Special reactions. If not containing too much iron or manganese gives an alumina reaction with nitrate of of cobalt. In other respects as the preceding. 

 * * * * *

Mineral. Turquoise

Formula. [. .. Al=]^{2}[. .. .. P] + 5[. H]. 

Behavior

 (1) in glass-bulb. Evolves water, occasionally decrepitates and turns black. 

 (2) in open tube. --

 (3) on charcoal. Turns brown, but remains infusible. 

 (4) in forceps. V. As on charcoal. Colors the outer flame green. 

 (5) in borax. In the oxidizing flame, gives a green bead, due to copper and iron. In reducing flame, opaque red. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Intumesces, then fuses to a semi-clear glass colored by iron. With more alkali yields an infusible mass. 

 (8) Special reactions. Gives the phosphoric-acid reaction. 

 * * * * *

Mineral. Wavellite

Formula. [Al=]F^{3} + 3([. .. Al=]^{4}[. .. .. P]^{3} + 18[. H]. )

Behavior

 (1) in glass-bulb. Evolves water and some fluorine, which attacks the glass. 

 (2) in open tube. --

 (3) on charcoal. Exfoliates and turns white. 

 (4) in forceps. V. As on charcoal. Colors the outer flame green, especially if moistened with SO^{3}. 

 (5) in borax. As alumina. Generally gives also a slight iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms an infusible white mass. 

 (8) Special reactions. With cobalt-solution on charcoal gives the alumina reaction. 

 * * * * *

Mineral. Spinel

Formula. [. R][. .. Al=]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. 

 (5) in borax. Gives a slight iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses partially and forms a porous mass. 

 (8) Special reactions. With nitrate of cobalt gives the alumina reaction. With nitre and carbonate of soda a slight manganese reaction. 

 * * * * *

SILICATES. 

The presence of silica in a mineral can easily be ascertained bytreating a small fragment in a bead of microcosmic salt. The baseswill dissolve out with more or less difficulty in the salt, and thesilica being insoluble will remain suspended in the bead, retainingthe original form of the fragment. In borax, the silicates of lime andmagnesia generally dissolve with considerable ease, but those ofalumina slowly and with difficulty. The silicates of lime are moreoverfrequently characterized by intumescence or ebullition, when heated inthe forceps in the blowpipe flame. The minerals presenting thischaracter are marked in the table. As the most convenient mode ofclassifying the silicates for blowpipe examination, the followingarrangement will be adopted:

TABLE I. --ANHYDROUS SILICATES. 

TABLE II. --HYDROUS SILICATES. 

FUSIBILITY. 

 I. Readily fusible to a bead. II. With difficulty fusible to a bead. III. Readily fusible on the edges. IV. With difficulty fusible on the edges. V. Infusible. 

 a. Afford a fluid bead with carbonate of soda. B. Afford a fluid bead with but little of that salt, but with a larger quantity a slaggy mass. C. Afford a slaggy mass only. 

This classification of minerals, according to their fusibility andtheir behavior with carbonate of soda, was originally proposed by_Berzelius_, and a table of the principal oxidized minerals arrangedaccording to these characters is given in his handbook of theblowpipe, and thence adopted, with some alterations by _Plattner_, inthe very excellent and detailed work already many times cited. In thefollowing general table I. , the more important silicates only areincluded, and in table II. Are enumerated in alphabetical order thosewhich afford characteristic reactions. 

TABLE I. 

Anhydrous Silicates. ________________________________________________________________________Fus. Alone and with NaC. 

 Mineral. Formula. ________________________________________________________________________I. A. Axinite ([. Ca][. Mg])^{3}([. .. B][. .. Si])^{3} + ([. .. Al=][. .. Fe=][. .. Mn=])^{2}([. .. Si][. .. B]) Int. Elaolite ([. K][. Na])^{3}[. .. Si] + 3[. .. Al=][. .. Si] Int. Garnet [. R]^{3}[. .. Si] + [. R=][. .. Si] Oligoclase [. Na][. .. Si] + [. .. Al=][. .. Si]^{2} Scapolite ([. Ca][. Na])^{3}[. .. Si]^{2} + 2[. .. Al=][. .. Si] Int. Spodumene ([. Li][. Na])^{3}[. .. Si]^{2} + 4[. .. Al=][. .. Si]^{2}Int. B. Asbestos As Hornblende to II. Augite ([. Ca][. Mg][. Fe][. Mn])^{3}[. .. Si]^{2} Int. Some var. Epidote ([. Ca]Fe)^{3}[. .. Si] + Int. To III. 2([. .. Al][. .. Fe][. .. Mn])[. .. Si] Hornblende ([. Ca][. Mg][. Fe])^{4} + ([. .. Si][. .. Al=])^{3} Int. Some var. Sodalite [. Na]^{3}[. .. Si] + 3[. .. Al=][. .. Si] + NaCl Int. To III. Vesuvian 3([. Ca][. Mg])^{3}[. .. Si] + 2([. .. Al=][. .. Fe=])[. .. Si] Int. C. Biaxial Mica [. K][. .. Si] + 4([. .. Al=][. .. Fe=])[. .. Si] to III. Hauyne ([. K][. Na])^{3}[. .. Si] + 3[. .. Al=][. .. Si] + [. Na][. .. Si] Tourmaline ([. R][. .. R=][. .. B])^{4}[. .. Si]^{3} Int. To V. 

II. A. Labradorite ([. Ca][. Na][. K])[. .. Si] + ([. .. Al=][. .. Fe=])[. .. Si] Lepidolite (KNaL)F + ([. .. Al=][. .. Fe=])[. .. Si]^{2}? Ryacolite [. K][. .. Si] + [. .. Al=][. .. Si]^{2} Albite [. Na][. .. Si] + [. .. Al=][. .. Si]^{3} b. Augite [. R]^{3}[. .. Si]^{2} some var. Actinolite ([. Ca][. Mg][. Fe])^{4}[. .. Si]^{3} Int. Diopside ([. Ca][. Mg])^{3}[. .. Si]^{2} | Humboltilite 2([. Ca][. Mg][. Na][. K])[. .. Si] + ([. .. Al=][. .. Fe=])[. .. Si] Sahlite As Augite Tremolite ([. Ca][. Mg])^{4}[. .. Si]^{3} c. Pyrope ([. Ca][. Mg][. Fe])^{3}[. .. Si] + Al[. .. Si] + m[. .. Cr]?

III. A. Anorthite ([. Ca][. Mg][. Na][. K])^{3}[. .. Si] + 3([. .. Al=][. .. Fe=])[. .. Si] Nepheline ([. Na][. K][. Ca])^{2}[. .. Si] + 2[. .. Al=][. .. Si] Obsidian [. .. Si], [. .. Al=], [. .. Fe=], [. Fe], [. Ca][. Na][. K] Int. Orthoclase ([. K][. Na])[. .. Si] + [. .. Al=][. .. Si]^{3} Petalite ([. Li][. Na])^{3}[. .. Si]^{4} + 4[. .. Al=][. .. Si]^{4} Pumice [. .. Si], [. .. Al=], [. Ca], [. K], [. Na], [. H] Int. B. Gadolinite ([. Y][. Ce][. La][. Fe][. Ca])^{3}[. .. Si] to V. Nephrite ([. Ca][. Mg][. Fe])^{4}[. .. Si]^{3}? Int. Wollastonite [. Ca]^{3}[. .. Si]^{2} | c. Iolite ([. Mg][. Fe])^{3}[. .. Si]^{2} + 3[. .. Al=][. .. Si]

IV. A. Beryl [. .. Be][. .. Si]^{2} + [. .. Al=][. .. Si]^{2} b. Diallage ([. Ca][. Mg][. Fe])^{3}([. .. Si][. .. Al=])^{2} Hypersthene ([. Mg][. Fe])^{3}[. .. Si]^{2} | c. Fuchsite ([. K]^{5}[. .. Si])^{2} + 9([. .. Al=][. .. Cr=])^{6}[. .. Si]^{6}V. A. Leucite [. K]^{3}[. .. Si]^{2} + [. .. Al=][. .. Si]^{2} b. Chondrodite ([. Mg], [. Mg]F)^{4}([. .. Si]SiF^{3}) Olivine ([. Mg][. Fe][. Ca])^{2}[. .. Si] c. Andalusite ([. .. Al=]Fe)^{3}[. .. Si]^{2} Chrysoberyl [. .. Be] + [. .. Al=] Kaynite [. .. Al=]^{3}[. .. Si]^{2} Pycnite 6[. .. Al=]^{3}[. .. Si]^{2} + (3[. .. Al=]F^{3} + 2[. .. Si]F^{3}) Topaz 6[. .. Al=]^{3}[. .. Si]^{2} + (3[. .. Al=]F^{3} + 2[. .. Si]F^{3}) Zircon [. .. Zr=][. .. Si] Staurolite ([. .. Al=]Fe)^{2}[. .. Si]________________________________________________________________________

Hydrous Silicates. ________________________________________________________________________Fus. Alone and with NaC. 

 Mineral. Formula. ________________________________________________________________________I. A. Analcime [. Na]^{3}[. .. Si]^{2} + 3[. .. Al=][. .. Si]^{2} + 6[. H] Int. Apophyllite ([. K], KF)([. .. Si], SiF^{3}) + 6[. Ca][. .. Si] + 15[. H] Int. Brewsterite ([. Sr][. Ba])[. .. Si] + [. .. Al=][. .. Si]^{3} + 5[. H] Int. Chabasite ([. Ca], [. Na], [. K])^{3}[. .. Si] + 3[. .. Al=][. .. Si]^{2} + 18[. H] Int. Lapis Lazuli [. .. Si], [. .. S], [. .. Al=], Fe, [. Ca], [. Na], [. H] Laumonite [. Ca]^{3}[. .. Si]^{2} + 3[. .. Al=][. .. Si]^{2} + 12[. H] Int. Mesotype ([. Na][. Ca])[. .. Si] + [. .. Al=][. .. Si] + 3[. H] Int. Natrolite [. Na][. .. Si] + [. .. Al=][. .. Si] + 2[. H] Int. Prehnite [. Ca]^{2}[. .. Si] + [. .. Al=][. .. Si] + [. H] Int. Scolezite [. Ca][. .. Si] + [. .. Al=][. .. Si] + 3[. H] Int. Thomsonite ([. Ca][. Na])^{3}[. .. Si] + 3[. .. Al=][. .. Si] + 7[. H] Int. Datholite 2[. Ca]^{3}[. .. Si] + [. .. B]^{3}[. .. Si]^{2} + 3[. H] Int. Heulandite [. Ca][. .. Si] + [. .. Al=][. .. Si]^{3} + 5[. H] Int. Stilbite [. Ca][. .. Si] + [. .. Al=][. .. Si]^{3} + 6[. H] Int. B. Okenite [. Ca]^{3}[. .. Si]^{4} + 6[. H] Int. Pectolite ([. Ca][. Na])^{4}[. .. Si]^{3} + [. H] Int. C. Saponite 2[. Mg]^{3}[. .. Si]^{2} + [. .. Al=][. .. Si] + 10 or 6[. H]II. A. Antrimolite 3([. Ca][. K])[. .. Si] + 5[. .. Al=][. .. Si] + 15[. H] Harmatome [. .. Ba][. .. Si] + [. .. Al=]S^{2} + 5[. H] b. Brevicite [. Na][. .. Si] + [. .. Al=][. .. Si] + 2[. H] Orthite [. R]^{3}[. .. Si] + [. .. R=][. .. Si] + ([. H]?) Int. 

III. C. Pitchstone [. .. Si], [. .. Al=], Fe, [. Mg][. Na], [. K][. H] Talc to V. [. Mg]^{6}[. .. Si]^{5} + 2[. H] Chlorite 3([. Mg]Fe)^{3}[. .. Si] + ([. .. Al=]Fe)^{2}[. .. Si] + 9[. H] Pinite [. .. Si], [. .. Al=], [. Fe], [. K], [. Mg], [. H]

IV. A. Steatite [. Mg]^{6}[. .. Si]^{5} + 4[. H] c. Gilbertite [. .. Si], [. .. Al=], [. Fe], [. Mg], [. H] Int. Meerschaum [. Mg][. .. Si] + [. H] | Serpentine [. Mg]^{9}[. .. Si]^{4} + 6[. H] |V. A. Gismondine ([. Ca][. K])^{2}[. .. Si] + 2[. .. Al=][. .. Si] + 9[. H]________________________________________________________________________

TABLE II. 

_______________________________________________________________________ |Analcime | If transparent becomes white and opaque when heated, | but on incipient fusion resumes its transparency and | then fuses to a clear glass. |Andalusite | When powdered and treated with cobalt solution on | charcoal, assumes a blue color. |Apophyllite | Fuses to a frothy white glass. |Axinite | Imparts a green color to the blowpipe flame, owing to | the presence of boracic acid. This reaction is | especially distinct, if the mineral be previously mixed | with fluorspar and bisulphate of potassa. |Beryl | Sometimes gives a chromium reaction in borax and | microcosmic salt. |Chabasite | Fuses to a white enamel. |Chondrodite | Evolves fluorine in the glass tube, both when heated | alone and with microcosmic salt. It sometimes also | gives off a trace of water. |Chrysoberyl | Is unattacked by carbonate of soda. With nitrate of | cobalt on charcoal the finely powdered mineral | assumes a blue color. |Datholite | Fuses to a clear glass and colors the flame green. |Diallage | Frequently gives off water in small quantity. |Fuchsite | Gives the chromium reaction with borax and microcosmic | salt. |Gadolinite | That from Hitteroe, if heated in a partially covered | platinum spoon to low redness, glows suddenly and | brilliantly. |Hauyne | Affords the sulphur reaction both on charcoal and when | fused with potassa. It contains both sulphur and | sulphuric acid. |Hypersthene | As Diallage. |Kyanite | As Andalusite. |Lapis Lazuli | Fuses to a white glass, and when treated with carbonate | of soda on charcoal, gives the sulphur reaction on | silver. |Laumonite | When strongly heated, exfoliates and curls up. |Lepidolite | Colors the blowpipe flame crimson, from lithia; also | gives the fluorine reaction with microcosmic salt. |Leucite | Some varieties, when treated with cobalt solution, | assume a blue color. |Meerschaum | In the glass bulb frequently blackens and evolves an | empyreumatic odor due to organic matter. When this is | burnt off, it again becomes white, and if moistened | with nitrate of cobalt solution and heated, assumes | a pink color. |Okenite | Behaves as Apophyllite. |Olivine | Some varieties give off fluorine, when fused with | microcosmic salt. |Pectolite | Similar to Apophyllite. |Petalite | Imparts a slight crimson color to the flame, like | Lepidolite. |Prehnite | As Chabasite. |Pycnite | Assumes a blue color, when treated with nitrate of | cobalt. Gives the fluorine reaction with microcosmic | salt. |Pyrope | Gives the chromium reaction with borax and microcosmic | salt. |Scolecite | Similar to Laumonite, but more marked. |Scapolite | Occasionally contains a small quantity of lithia, and | colors the flame red when fused with fluorspar and | bisulphate of potassa. |Sodalite | If mixed with one-fifth its volume of oxide of copper, | moistened to make the mixture cohere, and a small | portion placed upon charcoal and heated with the blue | oxidizing flame, the outer flame will be colored | intensely blue from chloride of copper. | |Spodumene | When not too strongly heated, colors the blowpipe | flame red, when more strongly, yellow. |Stilbite | As Chabasite. |Topaz | When heated, remains clear. Otherwise as Pycnite. |Tourmaline | Gives the boracic acid reaction with flourspar and | bisulphate of potassa. |Wollastonite | Colors the blowpipe flame faintly red from lime. |Zircon | The colored varieties become white or colorless and | transparent, when heated. Is only slightly attacked | by carbonate of soda. ______________|________________________________________________________

 * * * * *

 URANIUM. 

 * * * * *

Mineral. Pitchblende

Formula. [. U][. .. U=] essentially. 

Behavior

 (1) in glass-bulb. Evolves some water and a small quantity of sulphur, sulphide of arsenic and metallic arsenic. 

 (2) in open tube. Evolves SO^{2} and a white sublimate of arsenious acid. 

 (3) on charcoal. Gives off arsenical fumes. 

 (4) in forceps. III. Colors the flame blue beyond the assay, owing to the presence of Pb. Sometimes also green towards the point, due to Cu. 

 (5) in borax. The roasted mineral affords the uranium reaction. 

 (6) in mic. Salt. As borax. Also a small residue of silica. 

 (7) with carb. Soda. Infusible. Affords the characteristic Pb incrustation, and sometimes yields minute particles of Cu. 

 (8) Special reactions. --

 * * * * *

Mineral. Uranium ochre

Formula. [. .. U=][. H]^{2}. Behavior

 (1) in glass-bulb. Evolves water and assumes a red color. 

 (2) in open tube. --

 (3) on charcoal. V. In reducing flame assumes a green color. 

 (4) in forceps. --

 (5) in borax. Gives the uranium reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Uranite

Formula. ([. Ca] +[. .. U=]^{2})[. .. .. ]P + 8[. H]. 

Behavior

 (1) in glass-bulb. Evolves water and becomes yellow and opaque. 

 (2) in open tube. --

 (3) on charcoal. Fuses with intumescence to a black bead having a semi-crystalline surface. 

 (4) in forceps. --

 (5) in borax. Gives the uranium reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms an infusible yellow slag. 

 (8) Special reactions. Gives the PO^{5} reaction. 

 * * * * *

Mineral. Chalcolite

Formula. ([. Cu]+[. .. U=]^{2})[. .. .. P] + 8[. H]. 

Behavior

 (1) in glass-bulb. As uranite. 

 (2) in open tube. --

 (3) on charcoal. As uranite. 

 (4) in forceps. As uranite. 

 (5) in borax. In the oxidizing flame gives a green bead, which in the reducing flame becomes of an opaque red, from Cu. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. In reducing flame yields a metallic bead of Cu. 

 (8) Special reactions. As uranite. 

 * * * * *

 IRON. 

 * * * * *

Mineral. Iron pyrites

Formula. FeS^{2}. 

Behavior

 (1) in glass-bulb. Gives a considerable yellow sublimate of sulphur, and sometimes sulphide of arsenic. Also HS. 

 (2) in open tube. Sulphurous acid and sometimes arsenious acid are evolved. 

 (3) on charcoal. Gives off some sulphur, which burns with a blue flame. Residue fuses to a magnetic bead. 

 (4) in forceps. --

 (5) in borax. The roasted mineral gives a strong iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a black mass, which spreads out on charcoal and gives the sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Magnetic pyrites

Formula. [, Fe]^{5}[, , Fe=]. Behavior

 (1) in glass-bulb. --

 (2) in open tube. Evolves sulphurous acid. 

 (3) on charcoal. Fuses to a magnetic bead black on the surface, and with a yellow shining fracture. 

 (4) in forceps. --

 (5) in borax. As iron pyrites. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As iron pyrites. 

 (8) Special reactions. --

 * * * * *

Mineral. Mispickel

Formula. FeAs + FeS^{2}. 

Behavior

 (1) in glass-bulb. A red sublimate of AsS^{2} is first formed and then a black sublimate of metallic arsenic. 

 (2) in open tube. Sulphurous and arsenious acids are evolved, the latter forming a white sublimate. 

 (3) on charcoal. Gives off much arsenic forming a white incrustation and fuses to a magnetic globule. 

 (4) in forceps. --

 (5) in borax. As iron pyrites. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As iron pyrites. 

 (8) Special reactions. --

 * * * * *

Mineral. Magnetic iron ore

Formula. Fe^{3}O^{4}

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. In the blue flame, fuses on edges and remains magnetic. 

 (5) in borax. Gives the iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Specular iron Red haematite

Formula. Fe^{2}O^{3}

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. In the blue flame is converted into Fe^{2}O^{4}, and then behaves as the preceding. 

 (5) in borax. As magnetic iron ore. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Göthite

Formula. [. .. Fe][. H]. 

Behavior

 (1) in glass-bulb. Evolves water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. As specular iron. 

 (5) in borax. As specular iron. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Franklinite

Formula. ([. Fe][. Zn][. Mn]) ([. .. Fe=][. .. Mn=]). 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. Forms a white incrustation on the charcoal, which moistened with cobalt solution assumes a green color. 

 (4) in forceps. V. In the blue flame fuses on edges and and becomes magnetic. 

 (5) in borax. Gives the iron and manganese reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Affords a considerable white incrustation of ZnO. 

 (8) Special reactions. Gives a strong manganese reaction with nitre and carbonate of soda. 

 * * * * *

Mineral. Ilmenite

Formula. [. .. Ti=] and [. .. Fe=]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. In reducing flame fuses on edges and becomes magnetic. 

 (5) in borax. Gives the iron reaction. 

 (6) in mic. Salt. In oxidizing flame exhibits the iron reaction. In reducing flame assumes a deep brownish red color. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Chromic iron

Formula. [. Fe][. .. Cr=]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. As the preceding. 

 (5) in borax. Dissolves slowly and gives the chromium reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. On platinum foil with nitre and carbonate of soda affords a yellow mass of chromate of potassa. 

 (8) Special reactions. --

 * * * * *

Mineral. Lievrite

Formula. 3([. Fe][. Ca])^{3}[. .. Si] + 2[. .. Fe=][. .. Si]. 

Behavior

 (1) in glass-bulb. Occasionally gives off some water and turns black. 

 (2) in open tube. --

 (3) on charcoal. Fuses to a black globule, which in the reducing flame becomes magnetic. 

 (4) in forceps. I. In reducing flame is magnetic. 

 (5) in borax. Gives the iron reaction. 

 (6) in mic. Salt. Gives the iron and silica reactions. 

 (7) with carb. Soda. Fuses to a black opaque bead. 

 (8) Special reactions. Generally gives the manganese reaction with nitre and carbonate of soda. 

 * * * * *

Mineral. Chloropal

Formula. [. .. Fe=][. .. Si]^{2} + 3[. H]. 

Behavior

 (1) in glass-bulb. Decrepitates more or less, gives off much water and turns black. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. Loses color and turns black. 

 (5) in borax. Gives the iron reaction. 

 (6) in mic. Salt. Gives the iron and silica reaction. 

 (7) with carb. Soda. Fuses to a transparent green glass. 

 (8) Special reactions. --

 * * * * *

Mineral. Green earth

Formula. [. .. Si], [. Fe], [. .. Al=], [. Na], [. K], [. H], etc. 

Behavior

 (1) in glass-bulb. Gives off water and becomes darker in color. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. In reducing flame fuses on edges and colors the outer flame yellow ([. Na]) or violet ([. K]). 

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As the preceding. 

 (7) with carb. Soda. Forms a slaggy mass. 

 (8) Special reactions. --

 * * * * *

Mineral. Siderite

Formula. [. Fe][. . C]. 

Behavior

 (1) in glass-bulb. Occasionally decrepitates. Gives off CO^{2} and turns black and magnetic. 

 (2) in open tube. --

 (3) on charcoal. As in glass bulb. 

 (4) in forceps. Behaves similarly to the magnetic oxide. 

 (5) in borax. Gives the iron and manganese reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Behaves as an oxide. With nitre and carbonate of soda on platinum generally gives the manganese reaction. 

 (8) Special reactions. In acid dissolves with effervescense. 

 * * * * *

Mineral. Copperas

Formula. [. Fe][. .. S] + 7[. H]. 

Behavior

 (1) in glass-bulb. Gives off water, and, when strongly heated, SO^{2} and SO^{3}, which reddens litmus paper. 

 (2) in open tube. Evolves water and SO^{2}, which may be recognized by its odor. 

 (3) on charcoal. Loses water and SO^{2}, and is converted into [. .. Fe=]. 

 (4) in forceps. Gives off H and SO^{2}, and then behaves as the magnetic oxide. 

 (5) in borax. The roasted mineral affords an iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms sulphide of sodium and oxide of iron. The former is absorbed into the charcoal, and if cut out and laid upon silver and moistened gives the S reaction. 

 (8) Special reactions. If dissolved in water, and a strip of silver-foil be introduced into the solution, the metal remains untarnished. 

 * * * * *

Mineral. Vivianite

Formula. [. Fe]^{3}[. .. .. P] + 8[. H]. 

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. Froths up and then fuses to a grey metallic bead. 

 (4) in forceps. As on charcoal. Singes flame green ([. .. .. P]). 

 (5) in borax. Gives the iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. In reducing flame becomes magnetic and fuses to a black saggy mass. 

 (8) Special reactions. --

 * * * * *

Mineral. Iriphyline

Formula. ([. Fe][. Mn][. Li])^{3}[. .. .. P]. 

Behavior

 (1) in glass-bulb. Gives off water, having an alkaline reaction, and assumes a metallic lustre resembling graphite. 

 (2) in open tube. --

 (3) on charcoal. Fuses readily to a black magnetic bead with a metallic lustre. 

 (4) in forceps. I. On platinum wire colors the flame crimson ([. Li]) and green ([. .. .. P]), towards the point fuses to a black magnetic bead. 

 (5) in borax. Gives the iron and manganese reactions. 

 (6) in mic. Salt. Gives the iron reaction which overpowers that of the manganese. 

 (7) with carb. Soda. Forms an infusible porous mass, which under the reducing flame becomes magnetic. 

 (8) Special reactions. Gives the manganese reaction with nitre and carbonate of soda on platinum foil. 

 * * * * *

Mineral. Scorodite

Formula. [. .. Fe=][. .. .. As] + 4[. H]. 

Behavior

 (1) in glass-bulb. Evolves water. 

 (2) in open tube. Gives off water and AsO^{3}. 

 (3) on charcoal. Emits arsenical fume and in the reducing flame fuses to a magnetic mass having a metallic lustre. 

 (4) in forceps. I. As on charcoal. Colors the outer flame blue. 

 (5) in borax. The roasted mineral gives an iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. 

 (8) Special reactions. Gives the arsenic reactions. 

 * * * * *

Mineral. Cube ore

Formula. [. Fe]^{3}[. .. .. As] + [. .. Fe=]^{3}[. .. .. As]^{2} + 18[. H]. 

Behavior

 (1) in glass-bulb. Evolves much water. 

 (2) in open tube. As the preceding. 

 (3) on charcoal. As the preceding. 

 (4) in forceps. As the preceding. 

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. As the preceding. 

 * * * * *

 MANGANESE. 

 * * * * *

Mineral. Manganblende

Formula. MnS. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Gives off SO^{2} and becomes greyish green on surface. 

 (3) on charcoal. Is slowly roasted and converted into oxide. 

 (4) in forceps. V. 

 (5) in borax. The roasted mineral gives a strong manganese reaction. 

 (6) in mic. Salt. In the unroasted state, dissolves with much ebullition and detonation due to elimination of sulphide of phosphorus. The bead then exhibits the characteristic violet color of manganese. 

 (7) with carb. Soda. Forms a slaggy mass, which laid on silver and moistened, gives the sulphur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Pyrolusite

Formula. [. . Mn]. 

Behavior

 (1) in glass-bulb. Frequently gives off a small quantity of water and, when strongly heated, oxygen. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. 

 (5) in borax. Gives the manganese reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms a slaggy mass. 

 (8) Special reactions. --

 * * * * *

Mineral. Manganite

Formula. [. .. Mn=][. H]. 

Behavior

 (1) in glass-bulb. Gives off much water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. Exfoliates slightly. 

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. --

 * * * * *

Mineral. Psilomelane

Formula. ([. Ba], [. Ca], [. Mg], [. K]) [. . Mn] + [. H]. 

Behavior

 (1) in glass-bulb. Gives off water and, when strongly heated, oxygen. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. Colors flame faintly green(Ba) and red towards the point (Ca). 

 (5) in borax. As pyrolusite. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As pyrolusite. 

 (8) Special reactions. --

 * * * * *

Mineral. Wad

Formula. [. . Mn], [. Mn], [. H], also [. .. Fe=], [. .. Al=], [. Ba], [. Cu], [. .. Pb], [. .. Si], etc. 

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. Colors flame variously according to its composition. 

 (5) in borax. Gives the manganese reaction, more or less modified by the presence of other oxides. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As pyrolusite. 

 (8) Special reactions. Various according to composition. When strongly heated and then moistened has an alkaline reaction on red litmus paper. 

 * * * * *

Mineral. Rhodonite

Formula. [. Mn]^{3}[. .. Si]^{2}. 

Behavior

 (1) in glass-bulb. Gives off more or less water. 

 (2) in open tube. --

 (3) on charcoal. Under a strong flame fuses to a brown opaque bead. 

 (4) in forceps. II. As on charcoal. 

 (5) in borax. In the oxidizing flame gives the manganese reaction. In reducing flame the iron reaction. 

 (6) in mic. Salt. As in borax, but leaves an insoluble siliceous skeleton. 

 (7) with carb. Soda. With a small quantity of the alkali fuses to a black bead. With a larger quantity forms a slag. 

 (8) Special reactions. --

 * * * * *

Mineral. Diallogite

Formula. [. Mn][. . C]. 

Behavior

 (1) in glass-bulb. Frequently decrepitates and gives off more or less water. 

 (2) in open tube. --

 (3) on charcoal. If strongly heated and moistened has an alkaline reaction on litmus paper due to the presence of Ca. 

 (4) in forceps. V. Frequently colors the flame slightly red. 

 (5) in borax. Gives the manganese and iron reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms an infusible slag. 

 (8) Special reactions. In warm acid dissolves with much effervescence. 

 * * * * *

Mineral. Triplite

Formula. ([. . Mn][. Fe])^{4}[. .. .. P]. 

Behavior

 (1) in glass-bulb. Generally gives off more or less water. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. I. Colors the outer blowpipe flame green ([. .. .. P]). 

 (5) in borax. Gives the manganese and iron reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms an infusible mass. 

 (8) Special reactions. --

 * * * * *

 NICKEL AND COBALT. 

 * * * * *

Mineral. Millerite

Formula. NiS. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Evolves SO^{2}. 

 (3) on charcoal. Fuses with much ebullition to a magnetic bead. 

 (4) in forceps. --

 (5) in borax. The roasted mineral gives a nickel reaction, slightly modified by small quantities of iron and copper. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses to a slaggy mass, which on silver gives the sulphur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Coppernickel

Formula. Ni^{2}As. 

Behavior

 (1) in glass-bulb. Gives off a little AsO^{3}. 

 (2) in open tube. Gives off much AsO^{3} and some SO^{2} and falls to powder. 

 (3) on charcoal. Fuses to a magnetic bead, with the evolution of arsenic, which colors the flame blue. 

 (4) in forceps. --

 (5) in borax. The arsenical bead obtained by fusing the mineral on charcoal, if fused upon the same support with borax successively added and removed, gives firstly an iron reaction, then cobalt if present, and lastly nickel. 

 (6) in mic. Salt. If the residual bead which has been treated with borax be further treated with microcosmic salt, the nickel reaction will be obtained and sometimes a slight copper reaction. 

 (7) with carb. Soda. --

 (8) Special reactions. Affords a sublimate of metallic arsenic when treated with cyanide of potassium. 

 * * * * *

Mineral. Smaltine

Formula. CoAs. 

Behavior

 (1) in glass-bulb. When strongly heated generally evolves metallic arsenic. 

 (2) in open tube. Gives a crystalline sublimate of AsO^{3}. Also some SO^{2}. 

 (3) on charcoal. Gives off fumes of arsenic, and fuses to a dark grey magnetic bead, very brittle, colors flame blue. 

 (4) in forceps. --

 (5) in borax. As the preceding, but the cobalt being in large excess requires some time for its perfect oxidation, before the nickel reaction is exhibited. 

 (6) in mic. Salt. Gives the cobalt reaction, and after the cobalt has been, removed that of nickel. 

 (7) with carb. Soda. --

 (8) Special reactions. As the preceding. 

 * * * * *

Mineral. Glance cobalt

Formula. CoS^{2} + CoAs. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. As the preceding, but gives off more SO^{2}. 

 (3) on charcoal. Gives off S and As, and fuses to a magnetic bead. Colors flame blue. 

 (4) in forceps. --

 (5) in borax. Gives a cobalt and slight iron reaction when treated as the preceding minerals. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Gives a sulphur reaction of silver. 

 (8) Special reactions. As the preceding. 

 * * * * *

Mineral. Nickel glance

Formula. NiS^{2} + NiAs. 

Behavior

 (1) in glass-bulb. Decrepitates and gives an orange colored sublimate of AsS^{2}. 

 (2) in open tube. As the preceding. 

 (3) on charcoal. As the preceding. 

 (4) in forceps. --

 (5) in borax. As copper nickel. 

 (6) in mic. Salt. Gives the nickel reaction occasionally somewhat obscured by cobalt. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. As copper nickel. 

 * * * * *

Mineral. Ulmannite

Formula. NiS^{2} + Ni(AsSb)^{2}. 

Behavior

 (1) in glass-bulb. Gives a slight white sublimate of SbO^{3} and more or less AsS^{3}. 

 (2) in open tube. Gives off thick fumes of SbO^{3} and SbO^{5} with AsO^{3} and SO^{2}. 

 (3) on charcoal. As glance cobalt, but accompanied by dense fumes of SbO^{3}. 

 (4) in forceps. --

 (5) in borax. As copper nickel. 

 (6) in mic. Salt. As the preceding. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. As copper nickel generally, but arsenic is not always present. 

 * * * * *

Mineral. Cobalt pyrites

Formula. ([, Co][, Ni][, Fe]) ([, , Co=][, , Ni=][, , Fe=]). 

Behavior

 (1) in glass-bulb. When strongly heated gives off sulphur and becomes brown. 

 (2) in open tube. Gives off much SO^{2} and a small quantity of AsO^{3}. 

 (3) on charcoal. In the reducing flame small fragments fuse with the evolution of sulphur to a magnetic bead having a bronze colored fracture. 

 (4) in forceps. --

 (5) in borax. In the oxidizing flame on charcoal gives a violet colored glass. In the reducing flame the nickel is reduced and may collected in a gold bead. When the nickel is removed, the glass exhibits a slight iron reaction while warm. 

 (6) in mic. Salt. As in borax, but the reduction of the nickel is more difficult than in the latter flux. 

 (7) with carb. Soda. As glance cobalt. 

 (8) Special reactions. As copper nickel, but the amount of arsenic is usually very small. 

 * * * * *

Mineral. Emerald nickel

Formula. [. Ni]^{3}[. . C] + 6[. H]. 

Behavior

 (1) in glass-bulb. Gives off much water and turns black. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. --

 (5) in borax. Dissolves with much effervescence and gives the nickel reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms a slaggy mass. 

 (8) Special reactions. In warm dilute HCl dissolves with much effervescence. 

 * * * * *

Mineral. Cobalt Bloom

Formula. [. Co]^{3}[. .. .. As] + 8[. H]. 

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. Evolves arsenical fumes and in the reducing flame fuses to a dark grey bead of arsenide of cobalt. 

 (4) in forceps. In the point of the blue flame fuses and colors the outer flame blue (As). 

 (5) in borax. Gives the cobalt reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. Gives off arsenic with cyanide of potassium in glass tube. 

 * * * * *

Mineral. Earthy cobalt

Formula. [. Mn], [. Co], [. Cu], [. Fe], [. H], etc. 

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. Emits a slight smell of arsenic, but does not fuse. 

 (4) in forceps. Colors the flame blue. 

 (5) in borax. In oxidizing flame gives the cobalt reaction which obscures those of [. Mn], [. Cu], etc. In reducing flame occasionally gives the [. Cu] reaction. 

 (6) in mic. Salt. As in borax. If a saturated bead be treated on charcoal with tin in the reducing flame for a few seconds, the [. Cu] reaction is sometimes obtained. 

 (7) with carb. Soda. Forms an infusible mass. 

 (8) Special reactions. With carbonate of soda and nitre on platinum foil, gives a strong manganese reaction. 

 * * * * *

 ZINC. 

 * * * * *

Mineral. Zincblende

Formula. ZnS. 

Behavior

 (1) in glass-bulb. Decrepitates strongly. 

 (2) in open tube. Evolves SO and becomes white or yellow if containing iron. 

 (3) on charcoal. V. In the reducing flame incrusts the charcoal with ZnO; also with CdO, if that metal be present. 

 (4) in forceps. --

 (5) in borax. The roasted mineral gives a zinc reaction, and sometimes a slight iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. Moreover colors the flame blue. The fused alkali gives a S reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Red oxide of zinc

Formula. [. Zn]. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. In the reducing flame forms a thin incrustation of oxide of zinc on the charcoal. 

 (4) in forceps. V. 

 (5) in borax. Generally gives a manganese and slight iron reaction in addition to that of zinc. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. On charcoal, forms a thick incrustation of ZnO. 

 (8) Special reactions. With carbonate of soda and nitre on platinum foil gives manganese reaction. 

 * * * * *

Mineral. Electric calamine

Formula. 2[. Zn]^{3}[. .. Si] + 3[. H]

Behavior

 (1) in glass-bulb. Gives off water and becomes white and opaque. 

 (2) in open tube. --

 (3) on charcoal. --

 (4) in forceps. V. 

 (5) in borax. Dissolves to a clear glass, which cannot be rendered opaque by the intermittent flame. 

 (6) in mic. Salt. Dissolves to a clear glass, which becomes opaque on cooling. Silica remains insoluble. 

 (7) with carb. Soda. With carbonate of soda alone is infusible. With 2 parts of alkali and 1 of borax fuses to a glass and sets free [. Zn], which incrusts the charcoal. 

 (8) Special reactions. --

 * * * * *

Mineral. Calamine

Formula. [. Zn][. . C]. 

Behavior

 (1) in glass-bulb. Gives off CO^{2} and becomes opaque. 

 (2) in open tube. --

 (3) on charcoal. As the red oxide. Sometimes also gives a lead incrustation. 

 (4) in forceps. V. 

 (5) in borax. Gives a zinc reaction and frequently an iron and manganese reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Forms a thick incrustation of zinc, sometimes also of [. Pb] and [. Co]. 

 (8) Special reactions. Dissolves with much effervescence in cold acid. 

 * * * * *

 BISMUTH. 

 * * * * *

Mineral. Native bismuth

Formula. Bi. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Fuses and is converted into a yellow oxide. 

 (3) on charcoal. Fuses to a bead and incrusts the charcoal with oxide. 

 (4) in forceps. --

 (5) in borax. The oxide formed upon charcoal gives the bismuth reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Bismuthine

Formula. BiS. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Fuses with ebullition and gives of S and SO^{2}. 

 (3) on charcoal. Fuses with much spirting and in the reducing flame yields a metallic bead and incrusts the charcoal with oxide. 

 (4) in forceps. --

 (5) in borax. The oxide obtained upon charcoal gives the bismuth reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. The fused alkali gives the sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Bismuthblende

Formula. [. .. Bi=]^{2}[. .. Si]^{3}. 

Behavior

 (1) in glass-bulb. Turns yellow and, when strongly heated, fuses. 

 (2) in open tube. --

 (3) on charcoal. Fuses with ebullition to a brown globule forming an incrustation of [. .. Bi=] on the charcoal. 

 (4) in forceps. I. Fuses with ease to a yellow bead, coloring the outer flame bluish green, especially if moistened with HCl. This color is due to [. .. .. P]. 

 (5) in borax. Gives the bismuth and also an iron reaction. 

 (6) in mic. Salt. As in borax, but leaves a silicious skeleton. 

 (7) with carb. Soda. Fuses to a yellow mass. The bismuth is then reduced to the metallic state and partially volatilized, incrusting the charcoal beyond. 

 (8) Special reactions. --

 * * * * *

Mineral. Tetradymite

Formula. Bi, Te, S. 

Behavior

 (1) in glass-bulb. Occasionally decrepitates and then fuses, forming a greyish white sublimate immediately above the mineral fragment. 

 (2) in open tube. Fuses and gives off white fumes, part of which pass up the tube and part deposit immediately above the mineral. This latter if heated fuses to clear drops (TeO^{3}). The mineral residue becomes surrounded by fused [. .. Bi=], characterized by its yellow color. 

 (3) on charcoal. Fuses to a metallic bead, colors the outer flame bluish green (Te and Se) and incrusts the charcoal around with the orange [. .. Bi=], beyond which is a white incrustation partly consisting of [. .. Te]. 

 (4) in forceps. --

 (5) in borax. The yellow oxide obtained upon charcoal gives the bismuth reaction, and the white incrustation of bismuth and telluric acid. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. In the reducing flame yields a bead of metallic bismuth, part of which is part of the tellurium volatilized and incrusts the charcoal around. 

 (8) Special reactions. The fused alkaline mass gives the sulphur reaction on silver. Also gives the tellurium reaction with charcoal and carbonate of soda. 

 * * * * *

 LEAD. 

 * * * * *

Mineral. Galena

Formula. PbS. 

Behavior

 (1) in glass-bulb. Generally decrepitates and gives off a small quantity of sulphur. 

 (2) in open tube. Gives off SO^{2}, and when strongly heated, a white sublimate of [. Pb], [. S]. 

 (3) on charcoal. Fuses and is reduced affording a bead of metallic lead, and forming an incrustation of PbO on the charcoal. Colors the outer flame blue. 

 (4) in forceps. --

 (5) in borax. The oxide formed upon charcoal gives the lead reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. The fused alkali gives a sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Clausthalite

Formula. PbSe. 

Behavior

 (1) in glass-bulb. Decrepitates slightly. 

 (2) in open tube. Forms a sublimate of selenium, which is grey when thickly deposited, and red when thin. 

 (3) on charcoal. Gives off fumes smelling strongly of selenium and coloring the flame blue. In the reducing flame fuses partially and incrusts the charcoal with Se and PbO. After some time a black infusible mass alone remains. 

 (4) in forceps. --

 (5) in borax. The infusible residue obtained upon charcoal gives an iron and sometimes copper and cobalt reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. With carbonate of soda, oxalate of potash yields a metallic bead, the fused alkali laid upon silver and moistened produces a stain similar to that produced by sulfur. 

 (8) Special reactions. --

 * * * * *

Mineral. Jamesonite

Formula. [, Pb]^{3}[, , Sb]^{2}. 

Behavior

 (1) in glass-bulb. Fuses and gives off some sulphur, sulphide of antimony and antimony which condense in the neck of the bulb. 

 (2) in open tube. Fuses and emits dense white fumes of SbO^{3}, which pass off and redden blue litmus paper. 

 (3) on charcoal. Fuses with great ease evolving much SbO^{3} and PbO, which incrusts the charcoal around the mineral. When the fumes have ceased, a small bead of metallic lead remains. 

 (4) in forceps. --

 (5) in borax. The yellow incrustation formed upon charcoal gives the reaction of lead, and the white those of antimony. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. The fused alkali gives the sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Minium

Formula. Pb^{3}O^{4}. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. Is reduced first to litharge (PbO) and then to metallic lead which forms the usual incrustation. 

 (4) in forceps. Colors the outer flame blue. 

 (5) in borax. Gives the lead reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. 

 (8) Special reactions. --

 * * * * *

Mineral. Mendipite

Formula. PbCl + 2PbO. 

Behavior

 (1) in glass-bulb. Decrepitates slightly and assumes a yellow color. 

 (2) in open tube. --

 (3) on charcoal. Fuses readily and is reduced to metallic lead with the evolution of acid fumes. Forms a white incrustation of PbCl, and a yellow one of PbO. 

 (4) in forceps. As the preceding. 

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. 

 (8) Special reactions. Gives the chlorine reaction with CuO and microcosmic salt. 

 * * * * *

Mineral. Cerusite

Formula. [. Pb][. . C]. 

Behavior

 (1) in glass-bulb. Decrepitates, gives off CO^{2}, turns yellow and fuses. 

 (2) in open tube. --

 (3) on charcoal. Is reduced to metallic lead, incrusting the charcoal around with PbO. 

 (4) in forceps. As the preceding. 

 (5) in borax. Gives the lead reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. 

 (8) Special reactions. In nitric acid dissolves with much effervescence. 

 * * * * *

Mineral. Anglesite

Formula. [. Pb][. .. S]. 

Behavior

 (1) in glass-bulb. Decrepitates and gives off a small quantity of water. 

 (2) in open tube. --

 (3) on charcoal. In the oxidizing flame fuses to a clear bead, which becomes opaque on cooling. In reducing flame is reduced with much ebullition to a metallic bead and incrusts the charcoal around with PbO. 

 (4) in forceps. As the preceding. 

 (5) in borax. Gives the lead reaction and occasionally a slight iron and manganese reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Is reduced yielding a metallic lead bead. The fused alkaline mass gives a sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Pyromorphite

Formula. PbCl + 3[. Pb]^{3}[. .. .. P]. 

Behavior

 (1) in glass-bulb. Decrepitates, and when strongly heated for some time, gives a slight white sublimate of PbCl. 

 (2) in open tube. --

 (3) on charcoal. In oxidizing flame fuses to a bead having a crystalline surface on cooling, and forms a thin film of PbCl on the charcoal In reducing flame fuses without reduction and on cooling assumes a polyhedral form. Incrusts the charcoal slightly with PbO. 

 (4) in forceps. Fuses and colors the flame blue. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. Is reduced yielding a metallic bead and incrusting the charcoal with PbO. 

 (8) Special reactions. Gives the chlorine reaction with microcosmic salt and CuO. Also the phosphoric acid reactions. 

 * * * * *

Mineral. Mimetene

Formula. PbCl+ 3[. Pb]^{3}[. .. .. As]

Behavior

 (1) in glass-bulb. As the preceding. 

 (2) in open tube. --

 (3) on charcoal. Fuses, but less easily than the preceding, gives off AsO^{3} and incrusts the charcoal with PbCl. Finally is reduced to a metallic bead and forms an incrustation of PbO. 

 (4) in forceps. As the preceding. 

 (5) in borax. The oxide formed on charcoal gives the lead reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. Gives the chlorine reaction. 

 * * * * *

Mineral. Vanadinite

Formula. PbCl + 3[. Pb]^{3}[. .. V]?

Behavior

 (1) in glass-bulb. As pyromorphite. 

 (2) in open tube. --

 (3) on charcoal. The powdered mineral fuses fuses to a black shining mass, which in the reducing flame affords a metallic bead. Incrusts the charcoal first with a white film of PbCl and afterwards with PbO. 

 (4) in forceps. As pyromorphite. 

 (5) in borax. Dissolves readily to a clear glass, which, in the oxidizing flame, is yellow, while hot, and colorless when cold. In reducing flame becomes opaque, and on cooling green. 

 (6) in mic. Salt. In oxidizing flame is yellow while hot, becoming paler on cooling. In reducing flame brown while warm, and emerald green when cold. 

 (7) with carb. Soda. On platinum wire fuses to a yellow bead, which is crystalline on cooling. On charcoal yields a button of metallic lead. 

 (8) Special reactions. With microcosmic salt and CuO, gives the chlorine reaction. If fused in a platinum spoon with from 3 to 4 times its volume of [. K], [. .. S]^{2} it forms a fluid yellow mass having an orange color when cold. 

 * * * * *

Mineral. Crocoisite

Formula. [. Pb][. .. Cr]. 

Behavior

 (1) in glass-bulb. Decrepitates violently and assumes a dark color. 

 (2) in open tube. --

 (3) on charcoal. Fuses and detonates yielding Cr^{2}O^{3} and metallic lead, and forming an incrustation of PbO on the charcoal. 

 (4) in forceps. As pyromorphite. 

 (5) in borax. Dissolves readily and colors the glass yellow while warm, and green when cold. (See Chromium reaction. )

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. On platinum foil gives a dark yellow mass, which becomes paler on cooling. On charcoal yields a metallic button. 

 (8) Special reactions. Treated as above with [. K], [. .. S]^{2} forms a violet colored mass, which on solidifying becomes reddish and on cooling pale grey. 

 * * * * *

Mineral. Molybdate of lead

Formula. [. Pb][. .. M]. 

Behavior

 (1) in glass-bulb. As the preceding. 

 (2) in open tube. --

 (3) on charcoal. Fuses and is partly absorbed into the charcoal leaving a globule of metallic lead, which is partially oxidized and incrusts the charcoal. 

 (4) in forceps. As pyromorphite. 

 (5) in borax. Dissolves readily and gives the molybdena reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Yields metallic lead. 

 (8) Special reactions. Fused as above with [. K], [. .. S]^{2} forms a yellow mass, which becomes white on cooling. If this be dissolved in water and a piece of zinc introduced into the solution, the latter becomes blue. 

 * * * * *

Mineral. Scheeletine

Formula. [. Pb][. .. W]. 

Behavior

 (1) in glass-bulb. Decrepitates more or less. 

 (2) in open tube. --

 (3) on charcoal. Fuses to a bead incrusting the charcoal with PbO. The bead on cooling is crystalline and has a dark metallic surface. 

 (4) in forceps. As pyromorphite. 

 (5) in borax. Dissolves to a clear colorless glass, which in the reducing flame becomes yellow, and on cooling grey and opaque. 

 (6) in mic. Salt. Dissolves to a clear colorless glass, which in the reducing flame assumes a dusky blue color. After a time becomes opaque. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. With carbonate of soda and nitre gives the manganese reaction. 

 * * * * *

 COPPER. 

 * * * * *

Mineral. Native Copper

Formula. Cu. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. Fuses to a brilliant metallic bead, which on cooling becomes covered with a coating of black oxide. 

 (4) in forceps. Fuses and colors the outer flame blue. 

 (5) in borax. In the oxidizing flame dissolves and then gives the copper reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Vitreous Copper

Formula. Cu^{2}S. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Evolves SO^{2} and, when pulverized and gently heated for some time is converted into CuO. 

 (3) on charcoal. Fuses to a bead, which spirts considerably and gives off SO^{2}. When pulverized and gently roasted, is converted into CuO. 

 (4) in forceps. --

 (5) in borax. The roasted mineral gives the copper reaction, and sometimes also a slight iron-reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. In the reducing flame is decomposed, forming NaS and metallic copper. If the former be cut out and laid upon silver, it gives the sulfur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Copper pyrites

Formula. [, Cu=][, , Fe=]. 

Behavior

 (1) in glass-bulb. Decrepitates, sometimes gives a sublimate of sulphur and becomes bronze colored on the surface. 

 (2) in open tube. Evolves SO^{2} and is finally converted into a dark red mixture of Fe^{2}O^{3} and CuO. 

 (3) on charcoal. Fuses readily with much ebullition and is magnetic on cooling. 

 (4) in forceps. --

 (5) in borax. As the preceding; but when the copper has been removed by reducing on charcoal, the bead shows a strong iron color. 

 (6) in mic. Salt. As the preceding, but the color in the oxidizing flame is green, owing to the presence of iron. 

 (7) with carb. Soda. Yields a bead of metallic copper and some magnetic oxide of iron which remains on the charcoal. The fused gives a sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Fahlerz

Formula. ([, Cu=][, Ag][, Fe][, Zn])^{4} ([, , Sb][, , As]). 

Behavior

 (1) in glass-bulb. Sometimes decrepitates, fuses, and when very strongly heated, gives a red sublimate of [, , Sb] with [. .. Sb], also sometimes a black sublimate of [, Hg] and occasionally [, , As]. 

 (2) in open tube. Fuses and gives off thick fumes of SbO^{3} and SO^{2}, also generally AsO^{3}, leaving a black infusible residue. If Hg be present, it is sublimed and condenses in the tube in small drops. 

 (3) on charcoal. Fuses to a bead, which fumes strongly and incrusts the charcoal with SbO^{3}, and sometimes ZnO, which cannot be volatilized. Emits a strong smell of arsenic. 

 (4) in forceps. --

 (5) in borax. The residue obtained on charcoal thoroughly roasted gives a copper reaction, and when the latter has been removed by reduction upon charcoal, an iron reaction. 

 (6) in mic. Salt. As in the preceding. 

 (7) with carb. Soda. With this flux and a little borax yields a bead of metallic copper; on silver, the alkaline mass gives a sulphur reaction. 

 (8) Special reactions. If the copper bead obtained by fusing upon carbonate of soda be cupelled with assay lead, a silver bead will be obtained. Or if dissolved in nitric acid and a drop or two of HCl added, a white precipitate of AgCl will be formed, which may be collected and reduced with carbonate of soda upon charcoal. 

 * * * * *

Mineral. Tennatite

Formula. ([, Cu=][, Fe=])^{4}[, , As]. 

Behavior

 (1) in glass-bulb. Decrepitates occasionally and gives a red sublimate of [, , As]. 

 (2) in open tube. Evolves [. . S] and [. .. As], which condense and form a white sublimate. 

 (3) on charcoal. Fuses to a magnetic bead giving of arsenical and sulphurous fumes. 

 (4) in forceps. --

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As the preceding. 

 (7) with carb. Soda. Yields a copper bead and metallic iron in the form of a dark grey powder. The fused alkali gives the sulphur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Bournonite

Formula. ([, Pb]^{2}[, Cu=])[, , Sb]. 

Behavior

 (1) in glass-bulb. Decrepitates giving off sulfur and, when strongly heated, [, , Sb] and [. .. Sb]. 

 (2) in open tube. Evolves thick white fumes of [. .. Sb], [. .. .. Sb] and [. Pb][. .. Sb]. Also [. S]. 

 (3) on charcoal. Fuses readily and incrusts the charcoal with [. .. Sb] and [. Pb] leaving a dark colored bead. 

 (4) in forceps. --

 (5) in borax. If the bead obtained on charcoal be fused on that support in the reducing flame with borax, a slight iron reaction is obtained, and after a time a copper reaction. 

 (6) in mic. Salt. As with borax. 

 (7) with carb. Soda. Yields a bead of metallic copper and lead and incrusts the charcoal with [. .. Sb] and [. Pb]. The alkaline mass laid on silver and moistened gives the sulphur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Red oxide of copper

Formula. Cu^{2}O

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Is converted into the black oxide CuO. 

 (3) on charcoal. In the reducing flame is reduced, forming a bead of metallic copper. 

 (4) in forceps. Fuses and colors the the flame emerald green, or if previously moistened with HCl, blue. 

 (5) in borax. Gives the copper reaction. 

 (6) in mic. Salt. As with borax. 

 (7) with carb. Soda. Is reduced to a bead of metallic copper. 

 (8) Special reactions. --

 * * * * *

Mineral. Atacamite

Formula. CuCl + 3[. Cu] + 6[. H]. 

Behavior

 (1) in glass-bulb. Gives off much water, having an acid reaction, on test paper, and forms a light grey sublimate of CuCl. 

 (2) in open tube. --

 (3) on charcoal. Fuses, colors the flame blue, forms a brown and a pale grey incrustation on the charcoal, and is reduced to metallic copper, leaving a small quantity of slag. 

 (4) in forceps. Fuses and colors the outer flame intensely blue and green towards the point. 

 (5) in borax. Gives the copper reactions. 

 (6) in mic. Salt. As with borax. 

 (7) with carb. Soda. Is reduced, yielding a bead of metallic copper. 

 (8) Special reactions. --

 * * * * *

Mineral. Dioptase

Formula. [. Cu]^{3}[. .. Si]^{2} + 3[. H]. 

Behavior

 (1) in glass-bulb. Gives off water and turns black. 

 (2) in open tube. --

 (3) on charcoal. In the oxidizing flame becomes black. In the reducing flame red. 

 (4) in forceps. V. Colors the outer flame intensely green. 

 (5) in borax. Gives the copper reactions. 

 (6) in mic. Salt. As with borax. The silica remains undissolved. 

 (7) with carb. Soda. With a small quantity of carbonate of soda fuses to a bead, which on cooling is opaque and has a red fracture. With more alkali forms a slag, containing little beads of reduced copper. 

 (8) Special reactions. --

 * * * * *

Mineral. Malachite

Formula. [. Cu]^{2}[. . C] + [. H]. 

Behavior

 (1) in glass-bulb. Gives off water and turns black. 

 (2) in open tube. --

 (3) on charcoal. Fuses to a bead with a strong flame is reduced to metallic copper. 

 (4) in forceps. Fuses and colors the outer flame brilliantly green. 

 (5) in borax. Gives the copper reaction. 

 (6) in mic. Salt. As with borax. 

 (7) with carb. Soda. Yields metallic copper. 

 (8) Special reactions. Dissolves in HCl with much effervescence. 

 * * * * *

Mineral. Blue vitriol

Formula. [. Cu][. .. S] + 5[. H]. 

Behavior

 (1) in glass-bulb. Intumesces, gives off water and becomes white. 

 (2) in open tube. Strongly heated is decomposed, given off SO^{2} and being converted into CuO. 

 (3) on charcoal. As in the glass-bulb. Then fuses, coloring the outer flame green, and is reduced to metallic copper and [, Cu=]. 

 (4) in forceps. Fuses and colors the outer flame blue. 

 (5) in borax. The roasted mineral gives copper reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Yields metallic copper. The alkaline mass laid on silver gives S reaction. 

 (8) Special reactions. Gives the sulphuric acid reaction. 

 * * * * *

Mineral. Libethenite

Formula. [. Cu]^{4}[. .. .. P] + 2[. H]. 

Behavior

 (1) in glass-bulb. Gives off water and turns black. 

 (2) in open tube. --

 (3) on charcoal. Gradually heated, turns black and fuses to a bead, having a core of metallic copper. 

 (4) in forceps. Fuses but does not color the flame distinctly. On cooling is black and crystalline. 

 (5) in borax. Gives the copper reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. With much of the alkali is decomposed, yielding metallic copper. With small portions successively added first fuses and then intumesces, fuses with a strong flame, and is then absorbed into the charcoal, leaving metallic copper. 

 (8) Special reactions. Gives the phosphoric acid reaction. 

 * * * * *

Mineral. Olivenite

Formula. [. Cu]^{4}([. .. .. As][. .. .. P]) + [. H]. 

Behavior

 (1) in glass-bulb. Gives off water. 

 (2) in open tube. --

 (3) on charcoal. Fuses with detonation and the evolution of arsenical fumes to a brittle regulus, brown externally and having a white fracture. 

 (4) in forceps. Fuses and colors the outer flame green. On cooling has a crystalline surface. 

 (5) in borax. Gives the copper reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Is reduced, yielding metallic copper. 

 (8) Special reactions. Gives the arsenic reactions. 

 * * * * *

 ANTIMONY. 

 * * * * *

Mineral. Native antimony

Formula. Sb. 

Behavior

 (1) in glass-bulb. Fuses and, when strongly heated, volatilizes being redeposited in the tube as a dark grey sublimate. 

 (2) in open tube. Fuses and gives off dense white fumes, which are partly redeposited on the tube. Sometimes also gives off arsenical fumes in small quantity. 

 (3) on charcoal. Fuses and gives off dense white fumes, which thickly incrust the charcoal and color the flame blue immediately beyond the assay. 

 (4) in forceps. --

 (5) in borax. The oxide formed upon charcoal gives the antimony reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. The incrustation on the charcoal, if treated with nitrate of cobalt assumes the characteristic green color. 

 * * * * *

Mineral. Grey antimony

Formula. SbS^{3}. 

Behavior

 (1) in glass-bulb. Fuses readily and occasionally gives off a small quantity of sulphur. Strongly heated forms a brown sublimate of SbS^{3} and SbO^{3}. 

 (2) in open tube. Fuses and gives off SO^{2}, which passes off up the tube, and dense white fumes of SbO^{3} and SbO^{5} which are partly deposited in the tube. 

 (3) on charcoal. Fuses and is partly absorbed by the charcoal and partly volatilized, incrusting the charcoal with the characteristic white oxides. Colors the flame blue. 

 (4) in forceps. --

 (5) in borax. As the preceding. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. Fuses and is reduced, yielding metallic antimony, which behaves as the preceding mineral upon charcoal. The alkaline mass gives the sulphur reaction. 

 (8) Special reactions. As the preceding. 

 * * * * *

Mineral. Antimony blende

Formula. [, , Sb]^{2} + [. .. Sb]. 

Behavior

 (1) in glass-bulb. Fuses easily, gives off first SbO^{3} and afterwards an orange colored sublimate. Strongly heated, is decomposed and gives a black sublimate, which becomes brown on cooling. 

 (2) in open tube. As the preceding. 

 (3) on charcoal. As the preceding. 

 (4) in forceps. --

 (5) in borax. As native antimony. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. As native antimony. 

 * * * * *

Mineral. White antimony

Formula. SbO^{3}. 

Behavior

 (1) in glass-bulb. Is sublimed and recondensed in the neck of the tube. 

 (2) in open tube. As in the glass-bulb. 

 (3) on charcoal. Fuses with the evolution of dense white fumes, which incrust the surface of the charcoal. In the reducing flame is partly reduced, yielding metallic antimony. Colors flame blue. 

 (4) in forceps. Fuses and is volatilized, coloring the outer flame blue. 

 (5) in borax. Gives the antimony reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. In the reducing flame is reduced, yielding metallic antimony. 

 (8) Special reactions. As native antimony. 

 * * * * *

 ARSENIC. 

 * * * * *

Mineral. Native arsenic

Formula. As. 

Behavior

 (1) in glass-bulb. Sublimes without fusion and recondenses as a dark grey metallic sublimate, sometimes leaving a small residue. 

 (2) in open tube. If gently heated in a good current of air passes off as AsO^{3}, which is partly condensed as a white sublimate in the upper part of the tube. 

 (3) on charcoal. Passes off as AsO^{3}, which thinly incrusts the charcoal beyond the assay. 

 (4) in forceps. Colors the flame blue. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Realgar

Formula. AsS^{2}. 

Behavior

 (1) in glass-bulb. Fuses, enters into ebullition and is sublimed as a transparent red sublimate. 

 (2) in open tube. Gently heated passes off as SO^{2} and AsO^{3}, the latter of which is redeposited in the upper part of the tube. 

 (3) on charcoal. Fuses and passes off as arsenious and sulphurous acids. 

 (4) in forceps. Fuses and colors the flame blue. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. As on charcoal, except that the S combines with the alkali forming NaS, which on silver gives the sulphur reaction. 

 (8) Special reactions. --

 * * * * *

Mineral. Orpiment

Formula. AsS^{3}. 

Behavior

 (1) in glass-bulb. As the preceding, except that the sublimate is of a dark yellow color when cold. 

 (2) in open tube. As the preceding. 

 (3) on charcoal. As the preceding. 

 (4) in forceps. As the preceding. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. --

 * * * * *

Mineral. White arsenic

Formula. AsO^{3}. 

Behavior

 (1) in glass-bulb. Sublimes without fusion and re-condenses in white crystals. 

 (2) in open tube. --

 (3) on charcoal. Sublimes and is partly recondensed on charcoal forming a white incrustation. 

 (4) in forceps. Colors the flame blue. 

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. Heated with charcoal in a glass-tube sealed at one end, is reduced and metallic arsenic sublimes. 

 * * * * *

 MERCURY. 

 * * * * *

Mineral. Native mercury

Formula. Hg. 

Behavior

 (1) in glass-bulb. Volatilizes with little or no residue and recondenses in neck of bulb. 

 (2) in open tube. --

 (3) on charcoal. Is volatilized. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Cinnabar

Formula. HgS. 

Behavior

 (1) in glass-bulb. Volatilizes sometimes leaving a slight earthy residue, and re-condenses as a black sulphide. 

 (2) in open tube. If gently heated is decomposed into metallic mercury, which volatilizes and recondenses in the upper part of the tube, and SO^{2}, which passes off as is easily recognized by its odor and bleaching properties. 

 (3) on charcoal. Is volatilized, generally leaving a small earthy residue. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. With carbonate of soda and cyanide of potassium is decomposed and metallic mercury volatilized. 

 (8) Special reactions. When in the preceding experiment the mercury has been entirely dissipated, the alkaline residue laid on silver gives a sulphur reaction. 

 * * * * *

Mineral. Native amalgam

Formula. AgHg^{2}. 

Behavior

 (1) in glass-bulb. As native mercury, but leaves a residue of pure silver. 

 (2) in open tube. --

 (3) on charcoal. The mercury volatilizes leaving the silver, which fuses to a bead, and, in the oxidizing flame, incrusts the charcoal with its characteristic oxide. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

 SILVER. 

 * * * * *

Mineral. Native silver

Formula. Ag. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. --

 (3) on charcoal. Fuses and in a strong oxidizing flame forms an incrustation of dark brown oxide on the charcoal. If any antimony be present, it affords a crimson incrustation. 

 (4) in forceps. --

 (5) in borax. Gives the silver reactions. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. --

 (8) Special reactions. --

 * * * * *

Mineral. Antimonial silver

Formula. Ag^{2}Sb. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Gives off dense white fumes, which are partly deposited in the tube. 

 (3) on charcoal. Fuses, fumes strongly, forming a white incrustation, and when the antimony is nearly expelled a crimson one, a nearly pure silver bead remains. 

 (4) in forceps. --

 (5) in borax. The incrustation formed on charcoal gives an antimony reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. 

 (8) Special reactions. --

 * * * * *

Mineral. Silver glance

Formula. AgS. 

Behavior

 (1) in glass-bulb. --

 (2) in open tube. Gives off sulphurous acid. 

 (3) on charcoal. Gives off SO^{2} and is reduced to metallic silver. If impure, a small quantity of slag also remains. 

 (4) in forceps. --

 (5) in borax. The residual slag (if any) obtained upon charcoal gives an iron reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. As alone on charcoal. The alkaline mass gives a sulphur reaction on polished silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Stephanite

Formula. [, Ag]^{6}[, , Sb]. 

Behavior

 (1) in glass-bulb. Decrepitates, fuses and gives a slight sublimate of sulphide of antimony. 

 (2) in open tube. Fuses and gives off SO^{2} and dense white antimonial fumes. 

 (3) on charcoal. Fuses and incrusts the charcoal with antimonious acid, leaving Ag with some antimony. If the flame be continued, a red incrustation is formed and finally a bead of pure silver remains surrounded by a small slag. 

 (4) in forceps. --

 (5) in borax. The residual slag obtained on the charcoal gives an iron and copper reaction. 

 (6) in mic. Salt. As in borax. 

 (7) with carb. Soda. The silver is reduced and the antimony passes off in dense fumes. The fused alkali gives the sulphur reaction on silver. 

 (8) Special reactions. --

 * * * * *

Mineral. Pyargyrite

Formula. [, Ag]^{3}[, , Sb]. 

Behavior (1) in glass-bulb. Sometimes decrepitates, fuses readily, and, when strongly heated, gives a red sublimate of SbS^{3}. 

 (2) in open tube. As in the preceding. 

 (3) on charcoal. Fuses with much spirting and covers the charcoal with antimonial fumes. When the residual AgS is heated for some time in the oxidizing flame, a bead of pure silver is obtained. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. As the preceding. 

 (8) Special reactions. --

 * * * * *

Mineral. Proustite

Formula. [, Ag]^{3}[, , As]. 

Behavior

 (1) in glass-bulb. Fuses and at a low red heat affords a small sublimate of AsS^{3}. 

 (2) in open tube. Gradually heated it gives off AsO^{3} and SO^{2}. Sometimes also antimony fumes. 

 (3) on charcoal. As the preceding, except that a large quantity of AsO^{3} and but little SbO^{3} are given off. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. As stephanite, except that much arsenic is given off and but little antimony. 

 (8) Special reactions. --

 * * * * *

Mineral. Horn silver

Formula. AgCl. 

Behavior

 (1) in glass-bulb. Fuses, but undergoes no further change. 

 (2) in open tube. --

 (3) on charcoal. Fuses readily in the oxidizing flame. In the reducing flame is slowly reduced yielding metallic silver. 

 (4) in forceps. --

 (5) in borax. --

 (6) in mic. Salt. --

 (7) with carb. Soda. Is rapidly reduced to metallic silver. 

 (8) Special reactions. If cut up into small pieces mixed with oxide of copper and then heated before the oxidizing flame upon charcoal, it colors the flame blue. 

 THE END. 

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Transcriber's Notes:

 Text italicized in the original book is surrounded by '_'. 

 This book had many columnar tables, often split across pages. These have been transformed in data sheets for readability. 

 The notation ^{#} is used for superscripted numbers, indicating the composition of the various chemical compounds. 

 Some of the element symbols were differenced by markings that were not defined in the book, but are supposed to be valence markings. These have been transcribed as follows:

 '. ' or ', ' above element symbol [?. Symbol] or [?, Symbol] '-' above element symbol [=Symbol] '-' through element symbol [Symbol=] . .. So [. .. Al] where the original text had Al _ [=M] where the original text had M, , [, , Sb] where the original text had Sb . .. [. .. Fe=] where the original text had Fe, line through the Fe.