This etext was created by Gregory Walker, in Austin, Texas, for theDigital Daguerreian Archive Project--electronic texts from the dawn ofphotography. 

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The location of the illustrations in the text are marked by"[hipho_##. Gif]" on a separate line. 

I hope this etext inspires a wider interest in the origins ofphotography and in the modern practice of the Daguerreian Art. 

THE HISTORY AND PRACTICE OF THE ART OF PHOTOGRAPHY;

OR THE PRODUCTION OF PICTURES THROUGH THE AGENCY OF LIGHT. 

CONTAINING ALL THE INSTRUCTIONS NECESSARY FOR THE COMPLETE PRACTICE OFTHE DAGUERREAN AND PHOTOGENIC ART, BOTH ON METALLIC PLATES AND ON PAPER. 

By HENRY H. SNELLING. 

ILLUSTRATED WITH WOOD CUTS. 

New York: PUBLISHED BY G. P. PUTNAM, 155 Broadway, 1849. 

Entered according to act of Congress in the year 1849, by H. H. Snelling, in the Clerk's office, of the District Court of the SouthernDistrict of New York. 

New York: PRINTED BY BUSTEED & McCOY, 163 Fulton Street. 

TO EDWARD ANTHONY, ESQ. , AN ESTEEMED FRIEND. 

Whose gentlemanly deportment, liberal feelings, and strict integrityhave secured him a large circle of friends, this work is RespectfullyDedicated By the AUTHOR. 

 PREFACE. 

The object of this little work is to fill a void much complained of byDaguerreotypists--particularly young beginners. 

The author has waited a long time in hopes that some more able penwould be devoted to the subject, but the wants of the numerous, andconstantly increasing, class, just mentioned, induces him to wait nolonger. 

All the English works on the subject--particularly on the practicalapplication, of Photogenic drawing--are deficient in many minutedetails, which are essential to a complete understanding of the art. Many of their methods of operating are entirely different from, andmuch inferior to, those practised in the United States: theirapparatus, also, cannot compare with ours for completeness, utility orsimplicity. 

I shall, therefore, confine myself principally--so far as Photogenicdrawing upon metalic plates is concerned--to the methods practised bythe most celebrated and experienced operators, drawing upon French andEnglish authority only in cases where I find it essential to thepurpose for which I design my work, namely: furnishing a completesystem of Photography; such an one as will enable any gentleman, orlady, who may wish to practise the art, for profit or amusement, to doso without the trouble and expense of seeking instruction fromprofessors, which in many cases within my own knowledge has preventedpersons from embracing the profession. 

To English authors I am principally indebted for that portion of mywork relating to Photogenic drawing on paper. To them we owe nearlyall the most important improvements in that branch of the art. Besides, it has been but seldom attempted in the United States, andthen without any decided success. Of these attempts I shall speakfurther in the Historical portion of this volume. 

Every thing essential, therefore, to a complete knowledge of the wholeart, comprising all the most recent discoveries and improvements downto the day of publication will be found herein laid down. 

CONTENTS

 I. A BRIEF HISTORY OF THE ART. II. THE THEORY ON LIGHT. --THE PHOTOGRAPHIC PRINCIPLE III. SYNOPSIS OF MR. HUNT'S TREATISE ON "THE INFLUENCE OF THE SOLAR RAYS ON COMPOUND BODIES, WITH ESPECIAL REFERENCE TO THEIR PHOTOGRAPHIC APPLICATION. " IV. A FEW HINTS AND SUGGESTIONS TO DAGUERREOTYPISTS. V. DAGUERREOTYPE APPARATUS. VI. THE DAGUERREOTYPE PROCESS. VII. PAPER DAGUERREOTYPES. --ETCHING DAGUERREOTYPES. VIII. PHOTOGENIC DRAWING ON PAPER. IX. CALOTYPE AND CHRYSOTYPE. X. CYANOTYPE--ENERGIATYPE--CHROMATYPE--ANTHOTYPE--AMPHITYPE AND "CRAYON DAGUERREOTYPE. " XI. ON THE PROBABILITY OF PRODUCING COLORED PICTURES BY THE SOLAR RADIATIONS--PHOTOGRAPHIC DEVIATIONS--LUNAR PICTURES--DRUMMOND LIGHT. XII. ON COLORING DAGUERREOTYPES. XIII. THE PHOTOGRAPHOMETER. INDEX. 

INTRODUCTION

 New York, January 27, 1849. E. ANTHONY, ESQ. 

Dear Sir, --In submitting the accompanying "History and Practice ofPhotography" to your perusal, and for your approbation, I do so withthe utmost confidence in your ability as a practical man, long engagedin the science of which it treats, as well as your knowledge of thesciences generally; as well as your regard for candor. To you, therefore, I leave the decision whether or no I have accomplished mypurpose, and produced a work which may not only be of practical benefitto the Daguerrean artist, but of general interest to the readingpublic, and your decision will influence me in offering it for, orwithholding it from, publication. 

If it meets your approbation, I would most respectfully ask permissionto dedicate it to you, subscribing myself, With esteem, Ever truly yours, HENRY H. SNELLING

 New York, February 1st, 1849. Mr. H. H. SNELLING. 

Dear Sir--Your note of January 27th, requesting permission to dedicateto me your "History and Practice of Photography, " I esteem a highcompliment, particularly since I have read the manuscript of your work. 

Such a treatise has long been needed, and the manner in which you havehandled the subject will make the book as interesting to the readingpublic as it is valuable to the Daguerrean artist, or the amateurdabbler in Photography. I have read nearly all of the many works uponthis art that have emanated from the London and Paris presses, and Ithink the reader will find in yours the pith of them all, with muchpractical and useful information that I do not remember to have seencommunicated elsewhere. 

There is much in it to arouse the reflective and inventive faculties ofour Daguerreotypists. They have heretofore stumbled along with verylittle knowledge of the true theory of their art, and yet the qualityof their productions is far in advance of those of the French andEnglish artists, most of whose establishments I have had the pleasureof visiting I feel therefore, that when a sufficient amount oftheoretic knowledge shall have been added to this practical skill onthe part of our operators, and when they shall have been made fullyacquainted with what has been attained or attempted by others, a stillgreater advance in the art will be manifested. 

A GOOD Daguerreotypist is by no means a mere machine following acertain set of fixed rules. Success in this art requires personalskill and artistic taste to a much greater degree than the unthinkingpublic generally imagine; in fact more than is imagined by nine-tenthsof the Daguerreotypists themselves. And we see as a natural result, that while the business numbers its thousands of votaries, but few riseto any degree of eminence. It is because they look upon their businessas a mere mechanical operation, and having no aim or pride beyond theearning of their daily bread, they calculate what will be a fair percentage on the cost of their plate, case, and chemicals, leaving MIND, which is as much CAPITAL as anything else (where it is exercised, )entirely out of the question. 

The art of taking photographs on PAPER, of which your work treats atconsiderable length, has as yet attracted but little attention in thiscountry, though destined, as I fully believe, to attain an importancefar superior to that to which the Daguerreotype has risen. 

The American mind needs a waking up upon the subject, and I think yourbook will give a powerful impulse in this direction. In Germany a highdegree of perfection has been reached, and I hope your countrymen willnot be slow to follow. 

Your interesting account of the experiments of Mr. Wattles was entirelynew to me, and is another among the many evidences that when the age isfully ripe for any great discovery, it is rare that it does not occurto more than a single mind. 

Trusting that your work will meet with the encouragement which yourtrouble in preparing it deserves, and with gratitude for the undeservedcompliment paid to me in its dedication, I remain, very sincerely, Your friend and well wisher, E. ANTHONY. 

PHOTOGRAPHY. 

CHAP. I. 

A BRIEF HISTORY OF THE ART. 

As in all cases of great and valuable inventions in science and art theEnglish lay claim to the honor of having first discovered that ofPhotogenic drawing. But we shall see in the progress of this history, that like many other assumptions of their authors, priority in this isno more due them, then the invention of steamboats, or the cotton gin. 

This claim is founded upon the fact that in 1802 Mr. Wedgwood recordedan experiment in the Journal of the Royal Institution of the followingnature. 

"A piece of paper, or other convenient material, was placed upon aframe and sponged over with a solution of nitrate of silver; it wasthen placed behind a painting on glass and the light traversing thepainting produced a kind of copy upon the prepared paper, those partsin which the rays were least intercepted being of the darkest hues. Here, however, terminated the experiment; for although both Mr. Wedgwood and Sir Humphry Davey experimented carefully, for the purposeof endeavoring to fix the drawings thus obtained, yet the object couldnot be accomplished, and the whole ended in failure. "

This, by their own showing, was the earliest attempt of the Englishsavans. But this much of the principle was known to the Alchemists atan early date--although practically produced in another way--as thefollowing experiment, to be found in old books, amply proves. 

"Dissolve chalk in aquafortis to the consistence of milk, and add to ita strong solution of silver; keep this liquor in a glass bottle wellstopped; then cutting out from a piece of paper the letters you wouldhave appear, paste it on the decanter, and lay it in the sun's rays insuch a manner that the rays may pass through the spaces cut out of thepaper and fall on the surface of the liquor the part of the glassthrough which the rays pass will be turned black, while that under thepaper remains white; but particular care must be observed that thebottle be not moved during the operation. "

Had not the alchemists been so intent upon the desire to discover thefar famed philosopher's stone, as to make them unmindful of theaccidental dawnings of more valuable discoveries, this littleexperiment in chemistry might have induced them to prosecute a morethorough search into the principle, and Photogenic art would not now, as it is, be a new one. 

It is even asserted that the Jugglers of India were for many ages inpossession of a secret by which they were enabled, in a brief space, tocopy the likeness of any individual by the action of light. This fact, if fact it be, may account for the celebrated magic mirrors said to bepossessed by these jugglers, and probable cause of their power over thepeople. 

However, as early as 1556 the fact was established that a combinationof chloride and silver, called, from its appearance, horn silver, wasblackened by the sun's rays; and in the latter part of the last centuryMrs. Fulhame published an experiment by which a change of color waseffected in the chloride of gold by the agency of light; and gave it asher opinion that words might be written in this way. These incidentsare considered as the first steps towards the discovery of thePhotogenic art. 

Mr. Wedgwood's experiments can scarcely be said to be any improvementon them since he failed to bring them to practical usefulness, and hiscountrymen will have to be satisfied with awarding the honor of itscomplete adaptation to practical purposes, to MM. Niepce and Daguerreof France, and to Professors Draper, and Morse of New-York. 

These gentlemen--MM. Niepce and Daguerre--pursued the subjectsimultaneously, without either, however being aware of the experimentsof his colleague in science. For several years, each pursued hisresearches individually until chance made them acquainted, when theyentered into co-partnership, and conjointly brought the art almost toperfection. 

M. Niepce presented his first paper on the subject to the Royal Societyin 1827, naming his discovery Heliography. What led him to the studyof the principles of the art I have no means, at present, of knowing, but it was probably owing to the facts recorded by the Alchemists, Mrs. Fulhame and others, already mentioned. But M. Daguerre, who is acelebrated dioramic painter, being desirous of employing some of thesingularly changeable salts of silver to produce a peculiar class ofeffects in his paintings, was led to pursue an investigation whichresulted in the discovery of the Daguerreotype, or Photogenic drawingon plates of copper coated with silver. 

To this gentleman--to his liberality--are we Americans indebted for thefree use of his invention; and the large and increasing class ofDaguerrean artists of this country should hold him in the most profoundrespect for it. He was not willing that it should be confined to a fewindividuals who might monopolise the benefits to be derived from itspractice, and shut out all chance of improvement. Like a true, noblehearted French gentleman he desired that his invention should spreadfreely throughout the whole world. With these views he openednegociations with the French government which were concluded mostfavorably to both the inventors, and France has the "glory of endowingthe whole world of science and art with one of the most surprisingdiscoveries that honor the land. "

Notwithstanding this, it has been patented in England and the result iswhat might have been expected: English pictures are far below thestandard of excellence of those taken by American artists. I have seensome medium portraits, for which a guinea each had been paid, and takentoo, by a celebrated artist, that our poorest Daguerreotypists would beashamed to show to a second person, much less suffer to leave theirrooms. 

CALOTYPE, the name given to one of the methods of Photogenic drawing onpaper, discovered, and perfected by Mr. Fox Talbot of England, isprecisely in the same predicament, not only in that country but in theUnited States, Mr. Talbot being patentee in both. He is a man of somewealth, I believe, but he demands so high a price for a single right inthis country, that none can be found who have the temerity to purchase. 

The execution of his pictures is also inferior to those taken by theGerman artists, and I would remark en passant, that the Messrs. Meadexhibited at the last fair of the American Institute, (of 1848, ) fourCalotypes, which one of the firm brought from Germany last Spring, thatfor beauty, depth of tone and excellence of execution surpass thefinest steel engraving. 

When Mr. Talbot's patent for the United States expires and ouringenious Yankee boys have the opportunity, I have not the slightestdoubt of the Calotype, in their hands, entirely superceding theDaguerreotype. 

Let them, therefore, study the principles of the art as laid down inthis little work, experiment, practice and perfect themselves in it, and when that time does arrive be prepared to produce that degree ofexcellence in Calotype they have already obtained in Daguerreotype. 

It is to Professor Samuel F. B. Morse, the distinguished inventor ofthe Magnetic Telegraph, of New York, that we are indebted for theapplication of Photography, to portrait taking. He was in Paris, forthe purpose of presenting to the scientific world his Electro-MagneticTelegraph, at the time, (1838, ) M. Daguerre announced his splendiddiscovery, and its astounding results having an important bearing onthe arts of design arrested his attention. In his letter to me on thesubject, the Professor gives the following interesting facts. 

"The process was a secret, and negociations were then in progress, forthe disclosure of it to the public between the French government andthe distinguished discoverer. M. Daguerre had shown his results to theking, and to a few only of the distinguished savans, and by the adviceof M. Arago, had determined to wait the action of the French Chambers, before showing them to any other persons. I was exceedingly desirousof seeing them, but knew not how to approach M. Daguerre who was astranger to me. On mentioning my desire to Robert Walsh, Esq. , ourworthy Consul, he said to me; 'state that you are an American, theinventor of the Telegraph, request to see them, and invite him in turnto see the Telegraph, and I know enough of the urbanity and liberalfeelings of the French, to insure you an invitation. ' I was successfullin my application, and with a young friend, since deceased, thepromising son of Edward Delevan, Esq. , I passed a most delightful hourwith M. Daguerre, and his enchanting sun-pictures. My letter containingan account of this visit, and these pictures, was the firstannouncement in this country of this splendid discovery. "

"I may here add the singular sequel to this visit. On the succeedingday M. Daguerre paid me a visit to see the Telegraph and witness itsoperations. He seemed much gratified and remained with me perhaps twohours; two melancholy hours to him, as they afterwards proved; or whilehe was with me, his buildings, including his diorama, his studio, hislaboratory, with all the beautiful pictures I had seen the day before, were consumed by fire. Fortunately for mankind, matter only wasconsumed, the soul and mind of the genius, and the process were stillin existence. "

On his return home, Professor Morse waited with impatience for therevelation of M. Daguerre's process, and no sooner was it publishedthan he procured a copy of the work containing it, and at oncecommenced taking Daguerreotype pictures. At first his object wassolely to furnish his studio with studies from nature; but hisexperiments led him into a belief of the practicability of procuringportraits by the process, and he was undoubtedly the first whoseattempts were attended with success. Thinking, at that time, that itwas necessary to place the sitters in a very strong light, they wereall taken with their eyes closed. 

Others were experimenting at the same time, among them Mr. Wolcott andProf. Draper, and Mr. Morse, with his accustomed modesty, thinks thatit would be difficult to say to whom is due the credit of the firstDaguerreotype portrait. At all events, so far as my knowledge servesme, Professor Morse deserves the laurel wreath, as from him originatedthe first of our inumerable class of Daguerreotypists; and many of hispupils have carried the manipulation to very great perfection. Inconnection with this matter I will give the concluding paragraph of aprivate letter from the Professor to me; He says. 

"If mine were the first, other experimenters soon made better results, and if there are any who dispute that I was first, I shall have noargument with them; for I was not so anxious to be the first to producethe result, as to produce it in any way. I esteem it but the naturalcarrying out of the wonderful discovery, and that the credit was afterall due to Daguerre. I lay no claim to any improvements. "

Since I commenced the compilation of this work, I have had the pleasureof making the acquaintance of an American gentleman--James M. WattlesEsq. --who as early as 1828--and it will be seen, by what I have alreadystated, that this is about the same date of M. Niepce's discovery--hadhis attention attracted to the subject of Photography, or as he termedit "Solar picture drawing, " while taking landscape views by means ofthe camera-obscura. When we reflect upon all the circumstancesconnected with his experiments, the great disadvantages under which helabored, and his extreme youthfullness, we cannot but feel a nationalpride--yet wonder--that a mere yankee boy, surrounded by the deepestforests, hundred of miles from the populous portion of our country, without the necessary materials, or resources for procuring them, should by the force of his natural genius make a discovery, and put itin practical use, to accomplish which, the most learned philosophers ofEurope, with every requisite apparatus, and a profound knowledge ofchemistry--spent years of toil to accomplish. How much more latenttalent may now be slumbering from the very same cause which kept Mr. Wattles from publicly revealing his discoveries, viz; want ofencouragement--ridicule!

At the time when the idea of taking pictures permanently on paper bymeans of the camera-obscura first occurred to him, he was but sixteenyears of age, and under the instructions of Mr. Charles Le Seuer, (atalented artist from Paris) at the New Harmony school, Indiana. Drawing and painting being the natural bent of his mind, he wasfrequently employed by the professors to make landscape sketches in themanner mentioned. The beauty of the image of these landscapes producedon the paper in the camera-obscura, caused him to pause and admire themwith all the ardor of a young artist, and wish that by some means, hecould fix them there in all their beauty. From wishing he broughthimself to think that it was not only possible but actually capable ofaccomplishment and from thinking it could, he resolved it should bedone. 

He was, however, wholly ignorant of even the first principles ofchemistry, and natural philosophy, and all the knowledge he was enabledto obtain from his teachers was of very little service to him. To addto this, whenever he mentioned his hopes to his parents, they laughedat him, and bade him attend to his studies and let such moonshinethoughts alone--still he persevered, though secretly, and he met withthe success his perseverance deserved. 

For the truth of his statement, Mr. Wattles refers to some of our mostrespectable citizens residing at the west, and I am in hopes that Ishall be enabled to receive in time for this publication, aconfirmation from one or more of these gentlemen. Be that as it may, Ifeel confident in the integrity of Mr. Wattles, and can give hisstatement to the world without a doubt of its truth. 

The following sketch of his experiments and their results will, undoubtedly, be interesting to every American reader and although someof the profound philosophers of Europe may smile at his method ofproceeding, it will in some measure show the innate genius of Americanminds, and prove that we are not far behind our trans-atlantic brethrenin the arts and sciences. 

Mr. Wattles says: "In my first efforts to effect the desired object, they were feeble indeed, and owing to my limited knowledge ofchemistry--wholly acquired by questioning my teachers--I met withrepeated failures but following them up with a determined spirit, I atlast produced, what I thought very fair samples--but to proceed to myexperiments. "

"I first dipped a quarter sheet of thin white writing paper in a weaksolution of caustic (as I then called it) and dried it in an empty box, to keep it in the dark; when dry, I placed it in the camera and watchedit with great patience for nearly half an hour, without producing anyvisible result; evidently from the solution being to weak. I thensoaked the same piece of paper in a solution of common potash, and thenagain in caustic water a little stronger than the first, and when dryplaced it in the camera. In about forty-five minutes I plainlypercieved the effect, in the gradual darkening of various parts of theview, which was the old stone fort in the rear of the school garden, with the trees, fence, &c. I then became convinced of thepracticability of producing beautiful solar pictures in this way; but, alas! my picture vanished and with it, all--no not all--my hopes. Withrenewed determination I began again by studying the nature of thepreparation, and came to the conclusion, that if I could destroy thepart not acted upon by the light without injuring that which was soacted upon, I could save my pictures. I then made a strong solution ofsal. Soda I had in the house, and soaked my paper in it, and thenwashed it off in hot water, which perfectly fixed the view upon thepaper. This paper was very poor with thick spots, more absorbent thanother parts, and consequently made dark shades in the picture wherethey should not have been; but it was enough to convince me that I hadsucceeded, and that at some future time, when I had the means and amore extensive knowledge of chemistry, I could apply myself to itagain. I have done so since, at various times, with perfect success;but in every instance laboring under adverse circumstances. "

I have very recently learned, that, under the present patent laws ofthe United States, every foreign patentee is required to put hisinvention, or discovery, into practical use within eighteen monthsafter taking out his papers, or otherwise forfeit his patent. Withregard to Mr. Talbot's Calotype patent, this time has nearly, if notquite expired, and my countrymen are now at perfect liberty toappropriate the art if they feel disposed. From the statement of Mr. Wattles, it will be perceived that this can be done without dishonor, as in the first instance Mr. Talbot had no positive right to his patent. 

Photography; or sun-painting is divided, according to the methodsadopted for producing pictures, into

 DAGUERREOTYPE, CHROMATYPE, CALOTYPE, ENERGIATYPE, CHRYSOTYPE, ANTHOTYPE and CYANOTYPE, AMPHITYPE. 

CHAP. II. 

THE THEORY ON LIGHT. --THE PHOTOGRAPHIC PRINCIPLE

Some philosophers contend that to the existence of light alone we owethe beautiful effects produced by the Photogenic art, while others givesufficient reasons for doubting the correctness of the assumption. That the results are effected by a principle associated with light andnot by the luminous principle itself, is the most probable conclusion. The importance of a knowledge of this fact becomes most essential inpractice, as will presently be seen. To this principle Mr. Hunt givesthe name of ENERGIA. 

THE NATURE of Light is not wholly known, but it is generally believedto be matter, as in its motions it obeys the laws regulating matter. So closely is it connected with heat and electricity that there can belittle doubt of their all being but different modifications of the samesubstance. I will not, however, enter into a statement of the varioustheories of Philosophers on this head, but content myself with that ofSir Isaac Newton; who supposed rays of light to consist of minuteparticles of matter, which are constantly emanating from luminousbodies and cause vision, as odoriferous particles, proceeding fromcertain bodies, cause smelling. 

The effects of light upon other bodies, and how light is effected bythem, involve some of the most important principles, which if properlyunderstood by Daguerreotypists would enable them to improve and correctmany of the practical operations in their art. These effects we shallexhibit in this and the following chapters. Before we enter on thissubject it will be necessary to become familiar with the

DEFINITIONS of some of the terms used in the science of optics. 

Luminous bodies are of two kinds; those which shine by their own light, and those which shine by reflected light. 

Transparent bodies are such as permit rays of light to pass throughthem. 

Translucent bodies permit light to pass faintly, but withoutrepresenting the figure of objects seen through them. 

Opaque bodies permit no light to pass through them, but reflect light. 

A ray is a line of light. 

A beam is a collection of parallel rays. 

A pencil is a collection of converging, or diverging rays. 

A medium is any space through which light passes. 

Incident rays are those which fall upon the surface of a body. 

Reflected rays are those which are thrown off from a body. 

Parallel rays are such as proceed equally distant from each otherthrough their whole course. 

Converging rays are such as approach and tend to unite at any onepoint, as at b. Fig. 3. 

Diverging rays are those which continue to recede from each other, asat e. Fig. 3. 

A Focus is that point at which converging rays meet. 

MOTION OF LIGHT--Rays of light are thrown off from luminous bodies inevery direction, but always in straight lines, which cross each otherat every point; but the particles of which each ray consists are sominute that the rays do not appear to be impeded by each other. A rayof light passing through an aperture into a dark room, proceeds in astraight line; a fact of which any one may be convinced by going into adarkened room and admitting light only through a small aperture. 

[Illustration: Fig. 1 (hipho_1. Gif)]

Light also moves with great velocity, but becomes fainter as it recedesfrom the source from which it eminates; in other words, diverging raysof light diminish in intensity as the square of the distance increases. For instance let a fig. 1, represent the luminous body from which lightproceeds, and suppose three square boards, b. C. D. Severally one, four and sixteen square inches in size be placed; b one foot, c twofeet, and d four feet from a, it will be perceived that the smallestboard b will throw c into shadow; that is, obstruct all rays of lightthat would otherwise fall on c, and if b were removed c would in likemanner hide the light from d--Now, if b recieve as much light as wouldfall on c whose surface is four times as large, the light must be fourtimes as powerful and sixteen times as powerful as that which wouldfall on the second and third boards, because the same quantity of lightis diffused over a space four and sixteen times greater. These samerays may be collected and their intensity again increased. 

Rays of light are reflected from one surface to another; Refracted, orbent, as they pass from the surface of one transparent medium toanother; and Inflected, or turned from their course, by the attractionof opaque bodies. From the first we derive the principles on whichmirrors are constructed; to the second we are indebted for the power ofthe lenses, and the blessings of sight, --for the light acts upon theretina of the eye in the same manner as on the lens of a camera. Thelatter has no important bearing upon our subject. 

When a ray of light falls perpendicularly upon an opaque body, it isreflected bark in the same line in which it proceeds; in this case thereflected ray returns in the same path the incident ray traversed; butwhen a ray falls obliquely, it is reflected obliquely, that is, it isthrown off in opposite direction, and as far from the perpendicular aswas the incident ray, as shown at Fig. 2; a representing the incidentray and b the reflected. The point, or angle c made by the incidentray, at the surface of the reflector e f, with a line c d, perpendicular to that surface, is called the angle of incidence, whilethe angle formed by the reflected ray b and the perpendicular line d iscalled the angle of reflection, and these angles are always equal. 

[Illustration: Fig. 2 (hipho_2. Gif)]

It is by this reflection of light that objects are made visible; butunless light falls directly upon the eye they are invisible, and arenot sensibly felt until after a certain series of operations upon thevarious coverings and humors of the eye. Smooth and polished surfacesreflect light most powerfully, and send to the eye the images of theobjects from which the light proceeded before reflection. Glass, whichis transparent--transmitting light--would be of no use to us as amirror, were it not first coated on one side with a metalic amalgam, which interrupts the rays in their passage from the glass into the air, and throws them either directly in the incident line, or in an obliquedirection. The reason why trees, rocks and animals are not allmirrors, reflecting other forms instead of their own, is, that theirsurfaces are uneven, and rays of light reflected from an uneven surfaceare diffused in all directions. 

Parallel rays falling obliquely upon a plane mirror are reflectedparallel; converging rays, with the same degree of convergence; anddiverging rays equally divergent. 

Stand before a mirror and your image is formed therein, and appears tobe as far behind the glass as you are before it, making the angle ofreflection equal to that of incidence, as before stated. The incidentray and the reflected ray form, together, what is called the passage ofreflection, and this will therefore make the actual distance of animage to appear as far again from the eye as it really is. Any objectwhich reflects light is called a radiant. The point behind areflecting surface, from which they appear to diverge, is called thevirtual focus. 

Rays of light being reflected at the same angle at which they fall upona mirror, two persons can stand in such a position that each can seethe image of the other without seeing his own. Again; you may see yourwhole figure in a mirror half your length, but if you stand before onea few inches shorter the whole cannot be reflected, as the incident raywhich passes from your feet into the mirror in the former case, will inthe latter fall under it. Images are always reversed in mirrors. 

Convex mirrors reflect light from a rounded surface and disperse therays in every direction, causing parallel rays to diverge, divergingrays to diverge more, and converging rays to converge less--theyrepresent objects smaller than they really are--because the angleformed by the reflected ray is rendered more acute by a convex than bya plane surface, and it is the diminishing of the visual angle, bycausing rays of light to be farther extended before they meet in apoint, which produces the image of convex mirrors. The greater theconvexity of a mirror, the more will the images of the objects bediminished, and the nearer will they appear to the surface. Thesemirrors furnish science with many curious and pleasing facts. 

Concave mirrors are the reverse of convex; the latter being roundedoutwards, the former hollowed inwards--they render rays of light moreconverging--collect rays instead of dispersing them, and magnifyobjects while the convex diminishes them. 

Rays of light may be collected in the focus of a mirror to suchintensity as to melt metals. The ordinary burning glass is anillustration of this fact; although the rays of light are refracted, orpassed through the glass and concentrated into a focus beneath. 

When incident rays are parallel, the reflected rays converge to afocus, but when the incident rays proceed from a focus, or aredivergent, they are reflected parallel. It is only when an object isnearer to a concave mirror than its centre of concavity, that its imageis magnified; for when the object is farther from the mirror, thiscentre will appear less than the object, and in an inverted position. 

The centre of concavity in a concave mirror, is an imaginary pointplaced in the centre of a circle formed by continuing the boundary ofthe concavity of the mirror from any one point of the edge to anotherparallel to and beneath it. 

REFRACTION OF LIGHT:--I now pass to the consideration of the passage oflight through bodies. 

A ray of light failing perpendicularly through the air upon a surfaceof glass or water passes on in a straight line through the body; but ifit, in passing from one medium to another of different density, fallobliquely, it is bent from its direct course and recedes from it, either towards the right or left, and this bending is calledrefraction; (see Fig. 3, b. ) If a ray of light passes from a rarer intoa denser medium it is refracted towards a perpendicular in that medium;but if it passes from a denser into rarer it is bent further from aperpendicular in that medium. Owing to this bending of the rays oflight the angles of refraction and incidence are never equal. 

Transparent bodies differ in their power of bending light--as a generalrule, the refractive power is proportioned to the density--but thechemical constitution of bodies as well as their density, is found toeffect their refracting power. Inflammable bodies possess this powerto a great degree. 

The sines of the angle of incidence and refraction (that is, theperpendicular drawn from the extremity of an arc to the diameter of acircle, ) are always in the same ratio; viz: from air into water, thesine of the angle of refraction is nearly as four to three, whatever bethe position of the ray with respect to the refracting surface. Fromair into sulphur, the sine of the angle of refraction is as two toone--therefore the rays of light cannot be refracted whenever the sineof the angle of refraction becomes equal to the radius* of a circle, and light falling very obliquely upon a transparent medium ceases to berefracted; this is termed total reflection. 

* The RADIUS of a circle is a straight line passing from the centre tothe circumference. 

Since the brightness of a reflected image depends upon the quantity oflight, it is quite evident that those images which arise from totalreflection are by far the most vivid, as in ordinary cases ofreflection a portion of light is absorbed. 

I should be pleased to enter more fully into this branch of the scienceof optics, but the bounds to which I am necessarily limited in a workof this kind will not admit of it. In the next chapter, however, Ishall give a synopsis of Mr. Hunt's treatise on the "Influence of theSolar Rays on Compound Bodies, with especial reference to theirPhotographic application"--a work which should be in the hands of everyDaguerreotypist, and which I hope soon to see republished in thiscountry. I will conclude this chapter with a brief statement of theprinciples upon which the Photographic art is founded. 

SOLAR and Stellar light contains three kinds of rays, viz:

1. Colorific, or rays of color. 

2. Calorific, or rays of heat. 

3. Chemical rays, or those which produce chemical effects. 

On the first and third the Photographic principle depends. Inexplaining this principle the accompanying wood cuts, (figs. 3 and 4)will render it more intelligible. 

If a pencil of the sun's rays fall upon a prism, it is bent in passingthrough the transparent medium; and some rays being more refracted thanothers, we procure an elongated image of the luminous beam, exhibitingthree distinct colors, red, yellow and blue, which are to be regardedas primitives--and from their interblending, seven, as recorded byNewton, and shown in the accompanying wood cut. These rays beingabsorbed, or reflected differently by various bodies, give to naturethe charm of color. Thus to the eve is given the pleasure we derive inlooking upon the green fields and forests, the enumerable varieties offlowers, the glowing ruby, jasper, topaz, amethist, and emerald, thebrilliant diamond, and all the rich and varied hues of nature, bothanimate and inanimate. 

[Illustration: Fig. 3 (hipho_3. Gif)]

Now, if we allow this prismatic spectrum (b. Fig. 3. ) to fall upon anysurface (as at c. ) prepared with a sensitive photographic compound, weshall find that the chemical effect produced bears no relation to theintensity of the light of any particular colored ray, but that, on thecontrary, it is dispersed over the largest portion of the spectrum, being most energetic in the least luminous rays, and ever active overan extensive space, where no traces of light can be detected. Fig. 4, will give the student a better idea of this principle. It is a copy ofthe kind of impression which the spectrum, spoken of, would make on apiece of paper covered with a very sensitive photographic preparation. The white space a. Corresponds with the most luminous, or yellow ray, (5, Fig. 3) over limits of which all chemical change is prevented. Asimilar action is also produced by the lower end of the red ray c; butin the upper portion, however we find a decided change (as at d). Themost active chemical change, you will perceive, is produced by the raysabove the yellow a; viz. 4, 3, 2 and 1 (as at b) the green (4) beingthe least active, and the blue (3) and violet (1) rays the most so, theaction still continuing far beyond the point b which is the end of theluminous image. 

[Illustration: Fig. 4 (hipho_4. Gif)]

Suppose we wish to copy by the Daguerreotype, or Calotype process, anyobjects highly colored--blue, red and yellow, for instancepredominating--the last of course reflects the most light, the blue theleast; but the rays from the blue surface will make the most intenseimpression, whilst the red radiations are working very slowly, and theyellow remains entirely inactive. This accounts for the difficultyexperienced in copying bright green foliage, or warmly coloredportraits; a large portion of the yellow and red rays entering into thecomposition of both--and the imperfections of a Daguerreotype portraitof a person with a freckled face depends upon the same cause. 

A yellow, hazy atmosphere, even when the light is very bright, willeffectually prevent any good photographic result--and in the height ofsummer, with the most sensative process, it not unfrequently happensthat the most annoying failures arise from this agency of a yellowmedium. A building painted of a yellow color, which may reflect thesun's rays directly into the operator's room will have the same effect. Daguerreotypists, being ignorant of these facts, are very apt to chargetheir want of success to the plates, or chemicals, or any thing but thereal cause; and it would be well to bear these facts constantly in mindand as far as possible avoid them. This, may be accomplished, in ameasure, by a choice of location or by having the glass of your windowstinged with blue; or a screen of thin blue paper may be interposedbetween the light and sitter. In selecting subjects, all strikingcontrasts in color should be avoided, and sitters for portraits shouldbe cautioned not to wear anything that may produce the effect spokenof--dark dresses always being the best. 

The action of light both combines and decomposes bodies. For instance, chlorine and hydrogen will remain in a glass vessel without alterationif kept in the dark; but if exposed to the rays of the sun, theyimmediately enter into combination, and produce hydrochloric acid. Onthe other hand, if colorless nitric acid be exposed to the sun, itbecomes yellow, then changes to red, and oxygen is liberated by thepartial decomposition effected by the solar rays. 

Of the organic substances none are more readily acted upon by lightthan the various combinations of silver. 

Of these some are more, and others less sensitive. If Chloride ofsilver, which is a white precipitate formed by adding chloride ofsodium (common salt) to a solution of nitrate of silver, be exposed todiffused light, it speedily assumes a violet tint, and ultimatelybecomes nearly black. With iodide of silver, bromide of silver, ammonio-nitrate of silver, and other salts of this metal, the resultwill be much the same. 

Some bodies, which under the influence of light, undergo chemicalchanges, have the power of restoring themselves to their originalcondition in the dark. This is more remarkably displayed in the iodideof platinum, which readily recieves a photogenic image by darkeningover the exposed surfaces, but speedily loses it by bleaching in thedark. The ioduret of Daguerre's plate, and some other iodides, exhibitthe same peculiarity--This leads us to the striking fact, that bodieswhich have undergone a change of estate under the influence ofday-light have some latent power by which they can renovate themselves. Possibly the hours of night are as necessary to inanimate nature asthey are to the animate. During the day, an excitement which we do notheed, unless in a state of disease, is maintained by the influence oflight and the hours of repose, during which the equilibrium isrestored, are absolutely necessary to the continuance of health. 

Instead of a few chemical compounds of gold and silver, which at firstwere alone supposed to be photographic, we are now aware that copper, platinum, lead, nickel, and indeed, probably all the elements, areequally liably to change under the sun's influence. This fact may beof benefit to engravers, for if steel can be made to take photographicimpressions, the more laborious process of etching may be dispensedwith. In fact, in the latter part of this work, a process is describedfor etching and taking printed impressions from Daguerreotype plates. As yet this process has produced no decided beneficial results--butfuture experiments may accomplish some practical discovery of intrinsicvalue to the art of engraving. 

A very simple experiment will prove how essential light is to thecoloring of the various species comprising the vegetable and animalkingdoms. If we transplant any shrub from the light of day into a darkcellar, we will soon see it lose its bright green color, and becomeperfectly white. 

Another effect of light is that it appears to impart to bodies somepower by which they more readily enter into chemical combination withothers. We have already said that chlorine and hydrogen, if kept inthe dark, will remain unaltered; but if the chlorine alone bepreviously exposed to the sun, the chlorine thus solarised will unitewith the hydrogen in the dark. Sulphate of iron will throw down goldor silver from their solutions slowly in the dark; but if eithersolution be first exposed to sunshine, and the mixture be then made, inthe dark, the precipitation takes place instantly. Here is again, evidence of either an absorption of some material agent from thesunbeam, or an alteration in the chemical constitution of the body. Itwas from understanding these principles and applying them thatphilosophers were enabled to produce the Calotype, Daguerreotype, &c. For the effects and action of light on the camera, see Chapter V. 

Some advances have been made towards producing Photographic impressionsin color--the impossibility of which some of our best and oldestartists have most pertinaciously maintained. The colored image of thespectrum has been most faithfully copied, ray for ray, on paper spreadwith the juice of the Cochorus Japonica, (a species of plant) and thefluoride of silver; and on silver plate covered with a thin film ofchloride. The day may be still remote when this much to be desireddesideratum shall be accomplished in portrait taking; but I am led tohope that future experiments may master the secret which now causes itto be looked upon, by many, as an impossibility. 

That great advantages have resulted, and that greater still will resultfrom the discovery of the Photographic art, few will deny. Thefaithful manner in which it copies nature, even to the most minutedetails, renders it of much value to the painter; but a few minutessufficing to take a view that formerly would have occupied severaldays. Its superiority in portraits, over miniature or oil painting hasbeen tacitly acknowledged by the thousands who employ it to securetheir own, or a friends likeness, and by the steady increase in thenumber of artists who are weekly, aye daily springing up in every townand village in the land. 

CHAP. III. 

SYNOPSIS OF MR. HUNT'S TREATISE ON "THE INFLUENCE OF THE SOLAR RAYS ONCOMPOUND BODIES, WITH ESPECIAL REFERENCE TO THEIR PHOTOGRAPHICAPPLICATION. "

OXIDE OF SILVER exposed for a few hours to good sunshine, passes into amore decided olive color, than characterises it when first prepared byprecipitation from nitrate of silver. Longer exposure renders thiscolor very much lighter, and the covered parts, are found much darker, than those on which the light has acted directly. In some instanceswhere the oxide of silver has been spread on the paper a decidedwhitening process in some parts, after a few days exposure, is noticed. Oxide of silver dissolved in ammonia is a valuable photographic fluid;one application of a strong solution forming an exceedingly sensitivesurface. The pictures on this paper are easily fixed by salt or weakammonia. 

NITRATE OF SILVER. --This salt in a state of purity, does not appear tobe sensibly affected by light, but the presence of the smallest portionof organic matter renders it exceedingly liable to change underluminous influence. 

If a piece of nitrated paper is placed upon hot iron, or held near thefire, it will be found that at a heat just below that at which thepaper chars, the salt is decomposed. Where the heat is greatest, thesilver is revived, and immediately around it, the paper becomes a deepblue; beyond this a pretty decided green color results, and beyond thegreen, a yellow or yellow brown stain is made. This exhibits aremarkable analogy between heat and light, --before spoken of in chap. II--and is of some practical importance in the preparation of the paper. 

PRISMATIC ANALYSIS. --The method of accomplishing the prismaticdecomposition of rays of light by the spectrum has already beendescribed on pages 22 and 23. The color of the impressed spectrum, onpaper washed with nitrate of silver, is at first, a pale brown, whichpasses slowly into a deeper shade; that portion corresponding with theblue rays becoming a blue brown; and under the violet of a peculiarpinkey shade, a very decided green tint, on the point which correspondswith the least refrangible blue rays, may be observed, its limits ofaction being near the centre of the yellow ray, and its maximum aboutthe centre of the blue, although the action up to the edge of theviolet ray is continued with very little diminution of effect; beyondthis point the action is very feeble. 

When the spectrum is made to act on paper which has been previouslydarkened, by exposure to sunshine under cupro-sulphate of ammonia, thephenomena are materially different. The photographic spectrum islengthened out on the red or negative side by a faint but very visiblered portion, which extends fully up to the end of the red rays, as seenby the naked eye. The tint of the general spectrum, too, instead ofbrown is dark grey, passing, however, at its most refracted or positiveend into a ruddy brown. 

In its Photographic application, the nitrate of silver is the mostvaluable of the salts of that metal, as from it most of the otherargentine compounds can be prepared, although it is not of itselfsufficiently sensible to light to render it of much use. 

CHLORIDE OF SILVER. --This salt of silver, whether in its precipitatedstate, or when fused, changes its color to a fine bluish grey by a veryshort exposure to the sun's rays. If combined with a small quantity ofnitrate, the change is more rapid, it attains a deep brown, then slowlypasses into a fine olive, and eventually, after a few weeks, themetalic silver is seen to be revived on the surface of the salt. Greatdifferences of color are produced on chlorides of silver precipitatedby different muriates. Nearly every variety in combination with thenitrate, becomes at last of the same olive color, the followingexamples, therefore, have reference to a few minutes exposure, only, togood sunshine; it must also be recollected that the chloride of silverin these cases is contaminated with the precipitant. 

Muriate of ammonia precipitates chloride to darken to a fine chocolatebrown, whilst muriate of lime produces a brick-red color. Muriates ofpotash and soda afford a precipitate, which darkens speedily to a puredark brown, and muriatic acid, or aqueous chlorine, do not appear toincrease the darkening power beyond the lilac to which the purechloride of silver changes by exposure. This difference of colorappears to be owing to the admixture of the earth or alkali used withthe silver salt. 

The prismatic impression on paper spread with the chloride of silver isoften very beautifully tinted, the intensity of color varying with thekind of muriate used. Spread paper with muriate of ammonia or barytaand you obtain a range of colors nearly corresponding with the naturalhues of the prismatic spectrum. Under favorable circumstances the meanred ray, leaves a red impression, which passes into a green over thespace occupied by the yellow rays. Above this a leaden hue isobserved, and about the mean blue ray, where the action is greatest, itrapidly passes through brown into black, and through the mostrefrangible rays it gradually declines into a bluish brown, which tintis continued throughout the invisible rays. At the least refrangibleend of the spectrum, the very remarkable phenomenon has been observed, of the extreme red rays exerting a protecting influence, and preservingthe paper from that change, which it would otherwise undergo, under theinfluence of the dispersed light which always surrounds the spectrum. Not only the extreme red ray exerts this very peculiar property, butthe ordinary red ray through nearly its whole length. 

In photographic drawing this salt is of the utmost importance. Mr. Talbot's application of it will be given hereafter in another portionof this work. 

IODIDE OF SILVER--Perfectly pure, undergoes very little change underthe influence of light or heat; but if a very slight excess of thenitrate of silver be added it becomes infinitely more sensitive thanthe chloride. 

The spectrum impressed upon paper prepared with a weak solution of thehydriodate of potash presents some very remarkable peculiarities. Themaximum of intensity is found at the edge of the most refrangibleviolet rays, or a little beyond it, varying slightly according to thekind of paper used, and the quantity of free nitrate of silver present. The action commences at a point nearly coincident with the mean red ofthe luminous spectrum, where it gives a dull ash or lead color, whilethe most refrangible rays impress a ruddy snuff-brown, the change oftint coming on rather suddenly about the end of the blue or beginningof the violet rays of the luminous spectrum. Beyond the extreme violetrays, the action rapidly diminishes, but the darkening produced bythese invisible rays, extends a very small space beyond the point atwhich they cease to act on the chloride of silver. 

In its photographic application, it is, alone, of very little use; butin combination with other reagents it becomes exquisitely sensitive. With gallic acid and the ferrocyanate of potash it forms two of themost sensitive photographic solutions with which we are acquainted. These are used in the calotype process. 

IODURET OF SILVER. --If upon a plate of polished silver we place a smallpiece of iodine, and apply the heat of a lamp beneath the plate for amoment, a system of rings is speedily formed. The first ring, whichspreading constantly forms the exterior of the circle, is of a brightyellow color; within this, there arises, successively, rings of green, red and blue colors, and then again a fine yellow circle, centred by agreyish spot on the place occupied by the iodine. On exposing these tothe light, the outer yellow circle almost instantly changes color, theothers slowly, in the order of their position, the interior yellowcircle resisting for a long time the solar influence. These rings mustbe regarded as films of the ioduret of silver, varying, not only inthickness, but in the more or less perfect states of combination inwhich the iodine and metal are. The exterior circle is an ioduret in avery loose state of chemical agregation; the attractive forces increaseas we proceed towards the centre, where a well formed ioduret, orprobably a true iodide of silver, is formed, which is acted upon bysunlight with difficulty. The exterior and most sensitive filmconstitutes the surface of Daguerreotype plates. The changes whichthese colored rings undergo are remarkable; by a few minutes exposureto sunlight, an inversion of nearly all the colors takes place, the twofirst rings becoming a deep olive green; and a deep blue inclining toblack. 

The nature of the change which the ioduret of silver undergoes onDaguerreotype plates, through the action of light, Mr. Hunt considersto be a decided case of decomposition, and cites several circumstancesin proof of his position. These with other facts given by Mr. Hunt inhis great work on the Photographic art, but to voluminous to include ina volume of the size to which I am obliged to confine myself, should bethoroughly studied by all Daguerreotypists. 

PRISMATIC ANALYSIS. --The most refrangible portion of the spectrum, (ona Daguerreotype plate) appears, after the plate has been exposed to thevapor of mercury, to have impressed its colors; the light and delicatefilm of mercury, which covers that portion, assuming a fine blue tintabout the central parts, which are gradually shaded off into a palegrey; and this is again surrounded by a very delicate rose hue, whichis lost in a band of pure white. Beyond this a protecting influence ispowerfully exerted; and notwithstanding the action of the dispersedlight, which is very evident over the plate, a line is left, perfectlyfree from mercurial vapor, and which, consequently, when viewed by aside light, appears quite dark. The green rays are represented by aline of a corresponding tint, considerably less in size than theluminous green rays. The yellow rays appear to be without action, orto act negatively, the space upon which they fall being protected fromthe mercurial vapor; and it consequently is seen as a dark band. Awhite line of vapor marks the place of the orange rays. The red rayseffect the sensitive surface in a peculiar manner; and we have themercurial vapor, assuming a molecular arrangement which gives to it afine rose hue; this tint is surrounded by a line of white vapor, shadedat the lowest extremity with a very soft green. Over the spaceoccupied by the extreme red rays, a protecting influence is againexerted; the space is retained free from mercurial vapor and the bandis found to surround the whole of the least refrangible rays, and tounite itself with the band which surrounds the rays of greatestrefrangibility. This band is not equally well defined throughout itswhole extent. It is most evident from the extreme red to the green; itfades in passing through the blue, and increases again, as it leavesthe indigo, until beyond the invisible chemical rays it is nearly asstrong as it is at the calorific end of the spectrum. 

Images on Daguerreotype plates which have been completely obliteratedby rubbing may be restored, by placing it in a tolerably strongsolution of iodine in water. 

BROMIDE OF SILVER. --This salt, like the iodide, does not appear to bereadily changed by the action of light; but when combined with thenitrate of silver it forms a very sensitive photographic preparation. 

Paper prepared with this salt, blackens over its whole extent withnearly equal intensity, when submitted to the prismatic spectrum. Themost characteristic peculiarity of the spectrum is its extravagantlength. Instead of terminating at the mean yellow ray, the darkenedportion extends down to the very extremity of the visible red rays. Intint it is pretty uniformly of a grey-black over its whole extent, except that a slight fringe of redness is perceptible at the leastrefracted end. Beyond the red ray, an extended space is protected fromthe agency of the dispersed light, and its whiteness maintained; thusconfirming the evidence of some chemical power in action, over a spacebeyond the luminous spectrum, which corresponds with the rays of theleast refrangibility. 

This salt is extensively used in photographic drawing. 

PREPARATIONS OF GOLD. --Chloride of Gold, freed from an excess of acidis slowly changed under the action of light; a regularly increasingdarkness taking place until it becomes purple, the first action of thelight being to whiten the paper, which, if removed from the light atthis stage, will gradually darken and eventually develope the picture. This process may be quickened by placing the paper in cold water. 

Chloride of gold with nitrate of silver gives a precipitate of a yellowbrown color. Paper impregnated with the acetate of lead, when washedwith perfectly neutral chloride of gold, acquires a brownish-yellowhue. The first impression of light seems rather to whiten than darkenthe paper, by discharging the original color, and substituting for it apale greyish tint, which by slow degrees increases to a dark slatecolor; but if arrested, while yet, not more than a moderate ash grey, and held in a current of steam, the color of the parts acted upon bylight--and of that only--darkens immediately to a deep purple. 

Here I must leave the subject of the action of light upon metaliccompounds--referring to Mr. Hunts work for any further information thestudent may desire on the other metals--as I find myself going beyondmy limits. I cannot, however, entirely dismiss the subject withoutgiving a few examples of the action of light on the juices of plants, some of which produce very good photographic effect. 

CORCHORUS JAPONICA--The juice of the flowers of this plant impart afine yellow color to paper, and, so far as ascertained, is the mostsensitive of any vegetable preparation; but owing to its continuing tochange color even in the dark, photographic images taken on paperprepared with it soon fade out. 

WALL FLOWER. --This flower yields a juice, when expressed with alcohol, from which subsides, on standing, a bright yellow finely dividedfaecula, leaving a greenish-yellow transparent liquid, only slightlycolored supernatant. The faecula spreads well on paper, and is verysensitive to light, but appears at the same time to undergo a sort ofchromatic analysis, and to comport itself as if composed of two verydistinct coloring principles, very differently affected. The one onwhich the intensity and sub-orange tint of the color depends, isspeedily destroyed, but the paper is not thereby fully whitened. Apaler yellow remains as a residual tint, and this on continued exposureto the light, slowly darkens to brown. Exposed to the spectrum, thepaper is first reduced nearly to whiteness in the region of the blueand violet rays. More slowly, an insulated solar image is whitened inthe less refrangible portion of the red. Continue the exposure, and abrown impression begins to be percieved in the midst of the whitestreak, which darkens slowly over the region between the lower blue andextreme violet rays. 

THE RED POPPY yields a very beautiful red color, which is entirelydestroyed by light. When perfectly dried on paper the color becomesblue. This blue color is speedily discharged by exposure to the sun'srays, and papers prepared with it afford very interestingphotographs. -- Future experiments will undoubtedly more fully developethe photogenic properties of flowers, and practically apply them. 

Certain precautions are necessary in extracting the coloring matter offlowers. The petals of fresh flowers, carefully selected, are crushedto a pulp in a mortar, either alone or with the addition of a littlealcohol, and the juice expressed by squeezing the pulp in a clean linenor cotton cloth. It is then to be spread upon paper with a flat brush, and dried in the air. If alcohol be not added, it must be appliedimmediately, as the air changes or destroys the color instantly. 

Most flowers give out their coloring matter to alcohol or water--butthe former is found to weaken, and in some cases to dischargealtogether these colors; but they are in most cases restored in drying. Paper tinged with vegetable colors must be kept perfectly dry and indarkness. 

To secure an eveness of tint on paper it should be first moistened onthe back by sponging, and blotting off with bibulous paper. It shouldthen be pinned on a board, the moist side downwards, so that two of itsedges--the right and lower ones--project a little over those of theboard. Incline the board twenty or thirty degrees to the horizon, andapply the tincture with a brush in strokes from right to left, takingcare not to go over the edges which rests on the board, but to passclearly over those that project; and also observing to carry the tintfrom below upwards by quick sweeping strokes, leaving no dry spacesbetween them. Cross these with other strokes from above downwards, leaving no floating liquid on the paper. Dry as quickly as possible, avoiding, however, such heat as may injure the tint. 

CHAP. IV. 

A FEW HINTS AND SUGGESTIONS TO DAGUERREOTYPISTS. 

There are very few who may not be capable of practising thePhotographic art, either on paper, or metalic plates--but, like allother professions, some are more clever in its various processes thanothers. 

Impatience is a great drawback to perfect success, and combined withlaziness is a decided enemy. Besides this, no one can excel inPhotography who does not possess a natural taste for the fine arts, whois not quick in discerning grace and beauty--is regardless of theprinciples of perspective, foreshortening and other rules of drawing, and who sets about it merely for the sake of gain--without the leastambition to rise to the first rank, both in its practice and theory. There is no profession or trade in which a slovenly manner will notshow itself, and none where its effects will be more apparent than this. 

In order to be great in any pursuit, we must be ourselves, and keep allthings, in order. In your show and reception rooms, let neatnessprevail; have your specimens so placed--leaning slightly forward--asto obtain the strongest light upon them, and at the same time preventthat glassiness of appearance which detracts so materially from theeffect they are intended to produce. If possible, let the light be ofa north-western aspect, mellowed by curtains of a semitransparent hue. Your show-cases, at the door, should be kept well cleaned. I haveoften been disgusted while attempting to examine portraits in the casesof our artists, at the greasy coating and marks of dirty fingers uponthe glass and frame enclosing them. Believe it, many a good customeris lost for no other reason. 

In your operating room, dust should be carefully excluded. It shouldbe furnished with nothing apt to collect and retain dust; a carpet istherefore not only a useless article, but very improper. A bare flooris to be prefered; but if you must cover it use matting. There is noplace about your establishment where greater care should be taken tohave order and cleanliness; for it will prevent many failures oftenattributed to other causes. "A place for every thing, and every thingin its place, " should be an absolute maxim with all artists. Do notoblige the ladies, on going away from your rooms, to say--"That H. Is aslovenly man; see how my dress is ruined by sitting down in a chairthat looked as if it had just come out of a porter house kitchen andhad not been cleaned for six months. "

In choosing your operating room, obtain one with a north-westernaspect, if possible; and either with, or capable of having attached, alarge skylight. Good pictures may be taken without the sky-light, butnot the most pleasing or effective. 

A very important point to be observed, is to keep the camera perfectlyfree from dust. The operator should be careful to see that theslightest particle be removed, for the act of inserting theplate-holder will set it in motion, if left, and cause those littleblack spots on the plate, by which an otherwise good picture isspoiled. The camera should be so placed as to prevent the sun shininginto the lenses. 

In taking portraits, the conformation of the sitter should be minutelystudied to enable you to place her or him in a position the mostgraceful and easy to be obtained. The eyes should be fixed on someobject a little above the camera, and to one side--but never into, oron the instrument, as some direct; the latter generally gives a fixed, silly, staring, scowling or painful expression to the face. Careshould also be taken, that the hands and feet, in whatever position, are not too forward or back ward from the face when that is in goodfocus. 

If any large surface of white is present, such as the shirt front, orlady's handkerchief, a piece of dark cloth (a temporary bosom ofnankeen is best, ) may be put over it, but quickly withdrawn when theprocess is about two thirds finished. 

A very pleasing effect is given to portraits, by introducing, behindthe sitter, an engraving or other picture--if a painting, avoid thosein which warm and glowing tints predominate. The subject of thesepictures may be applicable to the taste or occupation of the personwhose portrait you are taking. This adds much to the interest of thepicture, which is otherwise frequently dull, cold and inanimate. 

Mr. J. H. Whitehurst of Richmond, Va. , has introduced a revolvingbackground, which is set in motion during the operation, and produces adistinctness and boldness in the image not otherwise to be obtained. The effect upon the background of the plate is equally pleasing; ithaving the appearance of a beautifully clouded sky. 

In practising Photographic drawing on paper, the student must bear inmind that it is positively essential, to secure success in the variousprocesses, to use the utmost precaution in spreading the solutions, andwashes from the combination of which the sensitive surfaces result. The same brush should always be used for the same solution, and neverused for any other, and always washed in clean water after having beenemployed. Any metalic mounting on the brushes should be avoided, asthe metal precipitates the silver from its solution. The brushesshould be made of camels or badger's hair and sufficiently broad andlarge to cover the paper in two or three sweeps; for if small ones beemployed, many strokes must be given, which leave corresponding streaksthat will become visible when submitted to light, and spoil the picture. 

These few preliminary hints and suggestions, will, I trust, be of someservice to all who adopt this pleasing art as a profession; and will, with a due attention to the directions given in the practical workingof the Daguerreotype, Calotype, etc. , ensure a corresponding measure ofsuccess. 

CHAP. V. 

DAGUERREOTYPE APPARATUS. 

The entire Daguerreotype process is comprised in seven distinctoperations; viz:

1. --Cleaning and polishing the plate. 

2. --Applying the sensitive coating. 

3--Submitting the plate to the action of light in the camera. 

4. --Bringing out the picture; in other words rendering it visible. 

5. --Fixing the image, or making it permanent--so that the light may nolonger act upon it. 

6. --Gilding: or covering the picture with a thin film of gold--whichnot only protects it, but greatly improves its distinctness and tone ofcolor. 

7. --Coloring the picture. 

For these various operations the following articles--which make up theentire apparatus of a Daguerrean artist--must be procured

1. --THE CAMERA. --(Fig. 5. ). The Camera Obscura of the Italianphilosophers, although highly appreciated, on account of the magicalcharacter of the pictures it produced, remained little other than ascientific toy, until the discovery of M. Daguerre. The value of thisinstrument is now great, and the interest of the process which it soessentially aids, universally admitted. A full description of it willtherefore be interesting. 

[Illustration: Fig. 5 (hipho_5. Gif)]

The camera is a dark box (a), having a tube with lenses (b) placed inone end of it, through which the radiations from external objects pass, and form a diminished picture upon the ground glass (g) placed at theproper distance in the box to receive it; the cap c covering the lensesat b until the plate is ready to receive the image of the object to becopied. 

Thus a (fig. 6. ) representing the lens, and b the object desired to berepresented, the rays (c, c) proceeding from it fall upon the lens, andare transmitted to a point, which varies with the curvature of theglass, where an inverted image (d) of b is very accurately formed. Atthis point, termed the focus, the sensitive photographic material isplaced for the purpose of obtaining the required picture. 

[Illustration: Fig. 5 (hipho_6. Gif)]

The great desideratum in a photographic camera is perfect lenses. Theyshould be achromatic, and the utmost transparency should be obtained;and under the closest inspection of the glass not the slightest wavyappearance, or dark spot should be detected; and a curvature which asmuch as possible prevents spherical aberration should be secured. Theeffect produced by this last defect is a convergence of perpendiculars, as for instance; two towers of any building, would be represented asleaning towards each other; and in a portrait the features would seemcontracted, distorted and mingled together, so as to throw the pictureout of drawing and make it look more like a caricature than a likeness. If the lens be not achromatic, a chromatic aberration takes place, which produces an indistinct, hazy appearance around the edges of thepicture, arising from the blending of the rays. 

The diameter and focal length of a lens must depend in a great measureon the distance of the object, and also on the superficies of the plateor paper to be covered. For portraits one of 1 1/2 inches diameter, and from 4 1/2 to 5 1/2 inches focus may be used; but for distantviews, one from 2 inches to 3 inches diameter, and from 8 to 12 inchesfocal length will answer much better. For single lenses, the aperturein front should be placed at a distance from it, corresponding to thediameter, and of a size not more than one third of the same. A varietyof movable diaphragms or caps, to cover the aperture in front, are veryuseful, as the intensity of the light may be modified by them and moreor less distinctness and clearness of delineation obtained. These capsalway come with Voitlander instruments and should be secured by thepurchaser. 

Though the single acromatic lens answers very well for copyingengravings; taking views from nature or art, for portraits the doubleshould always be used. The extensive manufacture of the most approvedcameras, both in Europe and in this country, obviates all necessity forany one attempting to construct one for their own use. Lenses are nowmade so perfect by some artisans that, what is called the "quickworking camera" will take a picture in one second, while the ordinarycameras require from eight to sixty. 

The camera in most general use is that manufactured by Voitlander andSon of Germany. Their small size consists of two seperate acromaticlenses; the first, or external one, has a free aperture of 1 1/2inches; the second, or internal, 1 5/8 inches; and both have the samefocus, viz: 5 3/4 inches. The larger size differs from the smaller. The inner lens is an achromatic 3 1/4 inches diameter, its focal lengthbeing 30 inches. The outer lens is a meniscus--that is bounded by aconcave and convex spherical surface which meet--having a focal lengthof 18 inches. For every distant view, the aperture in front iscontracted by a diaphram to 1/8 of an inch. By this means the light isreflected with considerable intensity and the clearness and correctnessof the pictures are truly surprising. 

THE AMERICA instruments are constructed on the same principle and manyof them are equally perfect. Mr. Edward Anthony of 205 Broadway, NewYork city, has constructed, and sold cameras fully equal to the Germanand for which Voitlander instruments have been refused in exchange bythe purchaser. 

The ordinary camera box (see fig. 5, a) varies in size to suit thetube, and is termed medium, half, or whole. Within the box is a slideto assist in regulating the focus, and in enlarging or diminishing thepicture. In one end of this slide is a springed groove into which theground-glass spectrum (g fig. 5) is slid, for the purpose of moreconveniently arranging the focus. After the plate is prepared it isplaced in the holder--partly seen at e, fig. 5, and covered with thedark slide f, fig. 5; the spectrum is then withdrawn and the holdertakes its place, and the lids d, d, are closed after removing the darkslide f. The plate is now ready to receive the image, and the cap cmay be removed to admit the light into the box. 

A camera constructed by Voitlander is thus described by Mr. Fisher. "It is made entirely of brass, so that variations of climate has noeffect upon it. It is very portable and when packed in its box, withall the necessary apparatus and materials for practising theDaguerreotype art, occupies but very little space. It is not, however, well adapted for the Calotype process. "

[Illustration: Fig. 7 (hipho_7. Gif)]

"The brass foot A (fig. 7. ), is placed on a table, or other firmsupport, and the pillar B. Screwed into it; the body of the camera, C, C is laid into the double forked bearing D. D. The instrument is nowproperly adjusted by means of the set screws, e, e, e, in the brassfoot, or it may be raised, lowered, or moved, by the telescope stand, and when correct, fixed by the screw b. The landscape to be delineatedis viewed either through the small lens, g, or with the naked eye onthe ground glass plate H, the focus being adjusted by the screw I. Theoptical part of the instrument consist of the small set of achromaticlenses already described. When the portrait or view is deliniated onthe ground glass to the entire satisfaction of the operator, the brasscap L is placed over the lens, and the entire body is removed away intothe dark, taking care not to disturb the position of the stand. Thebody is now detached at the part H, and the prepared paper or plateenclosed in the brass frame work introduced in its place; the whole isagain placed upon the pedestal, the brass cap L is removed, by whichthe paper or plate is exposed to the full influence of the light, afterwhich the cap is again replaced. 

Mr. Woodbridge, of this city, has constructed an instrument for takingfull length portraits on plates 10 by 13 inches, which is worthy ofsome notice. It is a double camera, consisting of two boxes, placed ina frame, one above the other, and so arranged as to slide easily up anddown. After the focus has been adjusted, on the object, in bothcameras, the plate is put into the upper box, in the manner alreadydescribed, until the superior portion of the figure is complete; it isthen placed in the second box and the lower extremities obtained. Theadjustment of the instrument is so complete that a perfect union of theparts is effected in the picture without the least possible line ofdemarkation being visible. Fig. 8 gives a front view of thisinstrument. 

[Illustration: Fig. 8 (hipho_8. Gif)]

Fig. 9 represents Talbot's Calotype Camera, --a very beautifulinstrument. 

The copying camera box has an extra slide in the back end, by which itmay be considerably lengthened at pleasure. 

II. --CAMERA STAND. --The best constructed stands are made of maple orblack walnut wood, having a cast iron socket (a, Fig. 12, ) throughwhich the sliding rod b passes, and into which the legs c, c, with ironscrew ferules are inserted. The platform d is made of two pieces, hinged together, as at e, and having a thumb screw for the purpose ofelevating or depressing the instrument. 

[Illustration: Fig. 9 (hipho_9. Gif)]

III. MERCURY BATH. --Fig. 13 gives a front view of the mercury bath nowin general use in this country for mercurializing and bringing out thepicture. It is quite an improvement on those first used. To make itmore portable it is in three pieces, a b and c; having a groove e onone side to receive the thermometre tube and scale by which the properdegree of heating the mercury is ascertained. Into the top are nicelyfitted two or three iron frames, with shoulders, for the plate to restin, suitable for the different sizes of plates. The bath is heated bymeans of a spirit lamp placed under it. From two to four ounces ofhighly purified mercury are put into the bath at a time. 

IV. PLATE BLOCKS AND VICES. --There are several kinds of this article inuse; I shall describe the two best only. 

[Illustration: Fig. 10 (hipho_10. Gif)]

Fig. 10 gives an idea of the improvement on the English hand block. The top a is perfectly flat and smooth--a little smaller than theplate, so as to permit the latter to project a very little allaround--having at opposite angles c c two clasps, one fixed the othermoveable, but capable of being fastened by the thumb screw d, so as tosecure the plate tightly upon the block. This block turns upon aswivle, b, which is attached to the table by the screw c, This block isonly used for holding the plate while undergoing the first operation incleaning. 

[Illustration: Fig. 11 (hipho_11. Gif)]

Fig. 11, shows the form of Lewis' newly patented plate vice, which fordurability, simplicity and utility is preferable to all others. Itconsists of a simple platform and arm of cast iron, the former, a, having a groove, d, in the centre for fixing the different sizes ofplate beds, e--and the latter supporting the leaves, e f. On this vicewhich is secured to a table, or bench, the plate receives its finishingpolish with rouge, or prepared lampblack. Mr. Lewis gives thefollowing directions for its use. "As the cam wears tighten it withthe adjusting screw (g) so as to allow the lever (f) to fall back intoa horizontal position; the plate being in its place at the time. Oilthe wearing parts occasionally. "

Some Daguerreotypists, however, use a foot lathe with buff wheels ofvarious forms; but this vice is sufficient for all ordinary purposes. 

[Illustration: Fig. 12 (hipho_12. Gif)]

[Illustration: Fig. 13 (hipho_13. Gif)]

V. COATING BOXES. --The usual form for iodine and bromine boxes is see, at figs. 14 and 15. They are far superior to those in use with theEnglish operators. Each consists of a wooden box (a, ) having firmlyembeded within it a stout glass jar (c), the edges of which are ground. Over this is placed the sliding cover b, double the length of the box, one half occupied by a piece of ground glass (e), tightly pressed uponthe glass pot by a spring (i) beneath the cross bar g, and fits the potso accurately that it effectually prevents the escape of the vapor ofthe iodine, bromine or other accelerating liquid contained therein. The other half of the lid is cut through, shoulders being left at thefour angles for the different sizes of frames, designed to recieve theplate while undergoing the coating process. When the plate is put intothe frame, the cover b is shoved under the second lid h and when coatedto the proper degree, it resumes its former position and the plate isplaced in the holder of the camera box. To test the tightness of thebox, light a piece of paper, put it into the pot and cover it with thesliding lid. The burning paper expels the air from the pot, and if itbe perfectly tight you may raise the whole box by the lid. 

VI. GLASS FUNNELS. --Are a necessary article to the Daguerreotypist, forfiltering water, solutions, &c. 

[Illustration: Fig. 14 (hipho_14. Gif)]

VII. GILDING STAND. --For nervous persons the gilding stand is a usefularticle. It is adjusted to a perfect level by thumb screws placed inits base. 

VIII. SPIRIT LAMPS. --The most useful and economical of those made arethe Britania, as they are less liable to break; and the tube for thewick being fastened to the body by a screw renders it less liable toget out of order or explode. Glass is the cheapest, and for an amateurwill do very well, but for a professed artist the Britania shouldalways be obtained. 

IX. COLOR BOX. --These are generally found on sale at the shops, andusually contain eight colors, four brushes and a gold cup. The artistwould, however, do well to obtain, all the colors mentioned in the lastchapter of this work, and be sure to get the very best, as there arevarious qualities of the same color, particularly carmine, which isvery expensive, and the cupidity of some may induce them to sell a poorarticle for the sake of larger profits. 

[Illustration: Fig. 15 (hipho_15. Gif)]

STILL. --Daguerreotypists should always use distilled water forsolutions, and washing the plate, as common water holds varioussubstances in solution which detract very materially from theexcellence of a photograph, and often gives much trouble, quiteunaccountable to many. For the purpose of distilling water theapparatus represented at Fig. 16 is both convenient and economical. 

It may be either wholly of good stout tin, or of sheet iron tinned onthe inside, and may be used over a common fire, or on a stove. A isthe body, which may be made to hold from one to four gallons of water, which is introduced at the opening b, which is then stopped by a cork. The tube d connects the neck a of the still with the worm tub, orrefrigerator B, at e, which is kept filled with cold water by means ofthe funnel c, and drawn off as fast as it becomes warm by the cock f. The distilled water is condensed in the worm--and passes off at thecock b, under which a bottle, or other vessel, should be placed toreceive it. The different joints are rendered tight by lute, or in itsabsence, some stiff paste spread upon a piece of linen and wrappedaround them will answer very well; an addition of sealing wax over allwill make them doubly secure. 

[Illustration: Fig. 16 (hipho_16. Gif)]

HYGROMETER. --This is an instrument never to be found, I believe, in therooms of our operators, although it would be of much use to them, forascertaining the quantity of moisture floating about the room; and asit is necessary to have the atmosphere as dry as possible to prevent anundue absorption of this watery vapor by the iodine &c. , and to procuregood pictures, --its detection becomes a matter of importance. Mason'shygrometer, manufactured by Mr. Roach and sold by Mr. Anthony, 205Broadway, New York is the best in use. 

It consists of two thermometre tubes placed, side by side, on a metalicscale, which is graduated equally to both tubes. The bulb of one ofthese tubes communicates, by means of a net-work of cotton, with aglass reservoir of water attached to the back of the scale. Fig. 17and 18 represent a front and back view of this instrument. 

Fig. 17 is the front view, showing the tubes with their respectivescales; the bulb b being covered with the network of cottoncommunicating with the reservoir c fig. 18, at d. 

[Illustration: Fig. 17 (hipho_17. Gif)]

[Illustration: Fig. 18 (hipho_18. Gif)]

The evaporation of the water from this bulb decreases the temperatureof the mercury in the tube b in proportion to the dryness of theatmosphere, and the number of degrees the tube b indicates below thatof the other, shows the real state of the atmosphere in the room; forinstance, if b stands at forty and a at sixty-one the room is in astate of extreme dryness, the difference of twenty-one degrees betweenthe thermometers--let a stand at any one point--gives this result. Ifthey do not differ, or there is only four or five degrees variation, the atmosphere of the room is very moist and means should be taken toexpel the superfluous quantity. 

HEAD RESTS. --The button head rest with chair back clip, A fig. 19--ismuch the best for travelling artists, as it can be taken apart, intoseveral pieces and closely packed; is easily and firmly fixed to theback of a chair by the clamp and screw a and b, and is readily adjustedto the head, as the buttons c, c and arms d, d are movable. 

Sometimes the button rest is fixed to a pole, which is screwed to thechair; but this method is not so secure and solid as the clip andoccupies more room in packing. Both the pole and clip, are furnishedin some cases with brass band rests instead of the button; but the onlyrecommendation these can possibly possess in the eyes of any artist, istheir cheapness. 

[Illustration: Fig. 19 (hipho_19. Gif)]

For a Daguerreotypist permanently located the independent ironhead-rest, B fig. 19, is the most preferable, principally on account ofits solidity. It is entirely of iron, is supported by a tripod (a) ofthe same metal and can be elevated by means of a rod (b) passingthrough the body of the tripod, to a height sufficient for a person, standing, to rest against. 

[Illustration: Fig. 20 (hipho_20. Gif)]

GALVANIC BATTERY. --This article is used for the purpose of giving toimperfectly coated plates a thicker covering of silver. The form ofbattery now most universally employed for electrotype, and othergalvanic purposes, is Smee's--Fig. 20. It consists of a piece ofplatinized silver, A, on the top of which is fixed a beam of wood, B, to prevent contact with the silver. A binding screw C is soldered onto the silver plate to connect it with any desired object, by means ofthe copper wire, e. A plate of amalgamated zinc, D, varying with thefancy of the operator from one half to the entire width of the silveris placed on each side of the wood. This is set into a glass vessel, P, --the extreme ends of the wood resting upon its edge--on which theacid with which it is charged has no effect. The jar is charged withsulphuric acid, (common oil of vitriol) diluted in eight parts its bulkof water. The zinc plates of the battery have been amalgamated withquicksilver, and when the battery is set into the jar of acid thereshould be no action percieved upon them when the poles F, G, are not incontact. Should any action be percieved, it indicates imperfectamalgamation; this can be easily remedied by pouring a little mercuryupon them immediately after removing them from the acid, taking care toget none upon the centre plate A. 

Directions for use. --A sheet of silver must be attached to the wireconnected with the centre plate A of the battery, and placed in thesilver solution--prepared as directed below. The plate to be silveredis first cleaned with diluted sulphuric acid, and then attached to thewire, G, proceeding from the zinc plates D, D, and placed in the silversolution, opposite the silver plate attached to the pole F, and abouthalf an inch from it. A slight effervescence will now be percievedfrom the battery, and the silver will be deposited upon theDaguerreotype plate, while at the same time a portion of the silverplate is dissolved. 

To prepare the solution of silver. --Dissolve one ounce of chloride ofsilver in a solution of two ounces of cyanide of potassium, previouslydissolved in one quart of water. The oxide of silver may be usedinstead of the chloride. This solution is put into a tumbler, or othervessel. 

[Illustration: Fig. 21 (hipho_21. Gif)]

[Illustration: Fig. 22 (hipho_22. Gif)]

This battery with the necessary articles for using it may be obtainedof E. Anthony, 205 Broadway, New York city. 

The other articles required by every operator may be simply enumerated, viz:

Sticking, or sealing paper. 

A pair of pliers, or forceps. 

Porcelain pans or dishes, for applying the hyposulphite of soda andwashing after the imagine is fixed, something in form like fig. 23. 

A support for holding the plate while being washed, like fig. 24. 

[Updater's note: Figures 23 and 24 were missing from the image set. ]

[Illustration: Fig. 25 (hipho_25. Gif)]

BUFF STICKS. --Fig. 25. --These are usually from one to three feet inlength, and about three inches wide--some think two and a halfsufficient. The underside, which is convex, is covered with a strip offinely prepared buckskin, or velvet, well padded with cotton or tow. 

All the articles enumerated in this chapter may be obtained, of thevery best quality and at the most reasonable rates, of Mr. E. Anthony, 205, Broadway, New York. 

CHAP. VI. 

THE DAGUERREOTYPE PROCESS. 

The process of taking Daguerreotype pictures differs very materiallyfrom all others of the photographic art, inasmuch as the production ofthe image is effected upon plates of copper coated with silver. Thesilver employed should be as pure as possible; the thickness of theplate is of little consequence, provided there be sufficient silver tobear the cleaning and polishing--is free from copper spots, issusceptible of a high polish, an exquisitely sensitive coating and apleasing tone. These qualities are possessed to an eminent degree bythe French plates. 

Having already enumerated the various processes--and the apparatusnecessary for the manipulation, I will here give a list of thechemicals to be used, and then proceed to explain them more fully. Therequisite chemicals are--

 NITRIC ACID, ROUGE, DRY IODINE, MERCURY, DRYING POWDER, HYPOSULPHITE OF SODA, CYANIDE OF POTASSIUM, CHLORIDE OF GOLD; OR ROTTENSTONE, HYPOSULPHITE OF GOLD. TRIPOLI, CHLORIDE OF SILVER. CHLORIDE OF IODINE, } their compounds, or other BROMINE } accelerating mixtures. 

FIRST OPERATION. --Cleaning and polishing the plate. --For this purposethe operator will require the--

Plate Blocks, Plate Vice

Spirit Lamp, Polishing Buffs, Nitric Acid, diluted in fifteen times its bulk of water

Galvanic Battery, to galvanize the plate, if it is too imperfect to beused without, previous cleaning it, as directed in the last chapter. 

Rottenstone, Tripoli, which is too often dispensed with. 

Rouge, or lampblack--the first being most preferable. The Englishoperators mix the two together. 

Prepared cotton Wool, or Canton flannel. If the first is used, itshould be excluded from the dust, as it is not so easily cleansed asthe latter. 

The plate is secured, with its silver side upward, to the block, by themeans described on page 58--having previously turned the edges backwardall around. The amount of cleaning a plate requires, depends upon thestate it is in. We will suppose one in the worst condition; dirty, scratched, and full of mercury spots, all of which imperfections aremore or less to be encountered. The mercury spots are to be removed byburning the plate. To do this hold the plate over the flame of aspirit lamp, more particularly under the mercury spots, until they, assume a dull appearance, when the lamp is to be removed, and the plateallowed to cool, after which it is attached to the block. 

Place the block upon the swivle, and hold it firmly with the left hand;take a small knot or pellet of cotton, or, if you like it better, asmall piece of canton flannel--wet it with a little diluted nitricacid; then sift some finely prepared rottenstone--Davie's, * if you canget it--upon it, and rub it over the plate with a continual circularmotion, till all traces of the dirt and scratches are removed; thenwipe off the rottenstone with a clean piece of cotton, adopting, asbefore, a slight circular motion, at the same time wiping the edges ofthe plate. Even the back should not be neglected, but throughlycleansed from any dirt or greasy film it may have received fromhandling. 

* Sold by E. Anthony. 

When this is thoroughly accomplished, mix a portion of your tripoliwith the dilute nitric acid, to the consistence of thick cream. Thentake a pellet of cotton and well polish the plate with this mixture, inthe same manner as with the rottenstone. Continue the process till, onremoving the tripoli with a clean pellet, the plate exhibits a clear, smooth, bright surface, free from all spots, or scratches. Any remainsof the acid on the plate may be entirely removed By sifting on it alittle Drying powder, and then wiping it carefully off with a finecamels hair brush, or duster. The finishing polish is now to be given. 

For this purpose the rouge--or a mixture of rouge and lamp-black, inthe proportion of one part of the former to seven of the latter--isused. It should be kept either in a muslin bag, or wide mouth bottle, over which a piece of muslin is tied--in fact, both the rottenstone andtripoli should be preserved from the dust in the same manner. With alittle of this powder spread over the buff--described on page 53--theplate recieves its final polish; the circular motion is changed for astraight one across the plate, which, if intended for a portrait, should be buffed the narrow way; but if, for a landscape or view of ahouse, the length way of the plate. 

The operation of cleaning the plate at first appears difficult andtedious, and many have been deterred from attempting this interestingart on that account; but, in reality, it is more simple in practicethan in description, and with a little patience and observation, alldifficulties are easily overcome. Great care must be taken to keep thebuff free from all extraneous matter, and perfectly dry, and when notin use it should be wrapped up in tissue paper, or placed in a tightbox. 

The plate should be buffed immediately before the sensitive coating isgiven; particles of dust are thus effectually removed; the temperatureof the plate is also increased by the friction, and the required tintmore readily obtained. 

SECOND OPERATION. --Applying the sensative coating. --The apparatus andchemicals required, are an

Iodine box--see fig. 14 page 53. 

Bromine box--similar to the iodine box but a trifle deeper. 

Dry Iodine. 

Bromine, or a compound of Bromine and Chloride of Iodine, or othersensitive mixture. 

Most of our best operators use the compound Bromine and Chloride ofIodine. In the early days of the Daguerreotype, Iodine alone was usedin preparing the plate, and although it still plays a very importantpart, other preparations, called accelerating liquids, quickstuff, &c. , are used, and the discovery of which has alone ensured the applicationof the Daguerreotype successfully to portrait taking--for when firstintroduced among us it took from five to ten minutes to produce atolerable good view, while now but the fraction of a minute is requiredto obtain an accurate likeness. 

To iodize the plate perfectly it must be placed over the iodine vaporimmediately after buffing. Scatter from a sixteenth to the eighth ofan ounce of dry iodine over the bottom of your coating box, andslightly cover it with cotton wool. The plate is then dropped into theframe b, fig. 12, with its silvered surface downward, and thrust underthe lid h. The bright surface of the plate is soon coated with a filmof iodine of a fine yellow color; it is then removed and placed overthe accelerating solution. It is not absolutely necessary to performthis operation in the dark, although a bright light should be avoided. Not so the next part of the process, viz; giving the plate its extremesensitiveness, or coating with the accelerating liquids. In this greatcaution should be used to prevent the slightest ray of light impringingdirectly on the plate, and in examining the color reflected lightshould always be used. A convenient method of examining the plate, isto make a small hole in the partition of the closet in which you coat, and cover it with a piece of tissue paper; by quickly turning the plateso that the paper is reflected upon it the color is very distinctlyshown. Most of our operators are not so particular in this respect asthey should be. 

ACCELERATING LIQUID. --Of these there are several kinds, which differboth in composition and action--some acting very quickly, others givinga finer tone to the picture although they are not so expeditious inthere operations; or in other words, not so sensitive to the action oflight. These are adopted by Daguerreotypists according to their tastesand prejudices. They are all applied in the same way as the coating ofiodine. The following are the best. 

Bromine water--This solution is much used in France, and, I shalltherefore give its preparation, and the method of using it, in thewords of M. Figeau. "Put into a bottle of pure water, a large excessof bromine; shake the mixture well, and before using it, let all thebromine be taken up. An ascertained quantity of this saturated wateris then diluted in a given quantity of distilled water, which gives asolution of bromine that is always identical. " M. Figeau recommends onepart of the saturated solution to thirty parts its bulk of water; butM. Lesebour finds it more manageable if diluted with forty times. Incase pure distilled, or rain water cannot be procured, a few drops ofnitric acid--say six to the quart--should be added to the common water. 

Put into the bromine box a given quantity of this solution, sufficientto well cover the bottom; the plate, having been iodized to a deepyellow, is placed over it; the time the plate should be exposed must beascertained by making a few trials; it averages from twelve to fortyseconds. When once ascertained, it is the same for any number ofplates, as the solution, which of course would become weaker andweaker, is changed after every operation, the same quantity beingalways put into the pot. 

Chloride of Iodine. --This is prepared by introducing chlorine gass intoa glass vessel containing iodine; the iodine is liquified, and theabove named compound is the result. Operators need not, however, be atthe trouble and expense of preparing it, as it can be obtainedperfectly pure of Mr. Anthony, 205 Broadway, N. Y. , as also all of thechemicals herein enumerated. The compound is diluted with distilledwater, and the plate submitted to its action till it is of a rosecolor. Chloride of iodine alone, is seldom if ever used now byAmerican operators, as it does not sufficiently come up to theirlocomotive principle of progression. The next is also eschewed by themajority, although many of our best artists use no other, on account ofthe very fine tone it gives to pictures. 

Bromide of Iodine. --This is a compound of bromine and chloride ofiodine. In mixing it, much depends upon the strength of theingredients; an equal portion of each being generally used. Perhapsthe best method of preparing it, is to make a solution in alcohol ofhalf an ounce of chloride of iodine, and add the bromine drop by drop, until the mixture becomes of a dark red color; then dilute withdistilled water, till it assumes a bright yellow. Put about half anounce of this compound into the pot, and coat over it to a violetcolor, change the solution when it becomes too weak to produce thedesired effect. 

Another. --Mix half an ounce of bromine with one ounce of chloride ofiodine, add two quarts pure distilled water, shake it well and let itstand for twelve hours then add twenty-five drops of muriatic acid, andlet it stand another twelve hours, occasionally shaking it up well. Dilute six parts of this solution in sixteen of water. Coat over dryiodine to a deep yellow, then over the sensitive to a deep rosecolor--approaching purple--then back, over dry iodine from four toeight seconds. 

Roach's Tripple Compound. --This is one of the very best sensitivesolutions, and is very popular among Daguerreotypists. To use this, take one part in weight, say one drachm, of the compound and dilute itwith twelve of water; coat over dry iodine to yellow, then over thecompound to a rosy red. The effect in the camera is quick, andproduces a picture of a fine white tone. 

Gurney's Sensitive. --This is another preparation of bromine, and givesa fine tone. To two parts of water add one of the sensitive, and putjust sufficient in the box to cover the bottom, or enable you to coatin from eight to ten seconds. Coat over dry iodine to a dark yellow, and over the quick till you see a good change, then back over the dryiodine from two to three seconds. 

Bromide of Lime, or Dry Sensitive. --This is a compound but recentlyintroduced, and is becoming somewhat of it favorite, owing principallyto the slight trouble it gives in its preparation, and the tone itimparts to the picture. To prepare it, fill your jar about half orquarter full of dry slacked lime, then drop into it bromine, till itbecomes a bright orange red. The plate is generally coated over thiscompound, after the iodine coating to yellow, to a violet, or plumcolor; but it will work well under any circumstances, the color beingof little consequence, if coated from thirty to ninety seconds, according to its strength. 

Mead's Accelerator. --I merely mention this as being in the market, notknowing any thing in regard to its merits. The directions given forits use are as follows: Mix one-third of a bottle with a wine glassfull of water, coat the plate over dry iodine to a dark gold color, then over the accelerator to a violet, then back over dry iodine, orchloride of iodine, from three to five seconds. 

Chloride of Bromine. --M. Bissou, a French experimentalist, has foundthat bromine associated with chlorine, prepared in a similar manner tochloride of iodine, already described, a solution of bromine beingsubstituted for the iodine, is a very sensitive solution; by means ofit daguerreotype proofs are obtained in half a second, and, thus veryfugitive subjects are represented, making it the very best compound fortaking children. So quick is its operation, that even persons oranimals may be taken in the act of walking. 

Hungarian Liquid. --This, I believe, has never been used here, orimported into this country, and the composition of it is not generallyknown, even in Europe, where it has taken precedence of all others. Itacts quickly and with considerable certainty. It is used by dilutingit with from ten to fifteen times its bulk of water, putting asufficient quantity into the jar to cover the bottom. The plate beingpreviously iodized to a light yellow, is submitted to this mixture tillit assumes a light rose tint. 

Bromine and Fluoric Acid, in combination, are used by some Daguerreanartists as a sensitive, but any of the above compounds are better;besides this, the fluoric acid is a dangerous poison, and the quickmade from it will not repay the risk to the health in using it. 

As I have before said, great caution should be observed in examiningthe color of the plate, even by the feeble light allowed, which, whenattained, must be immediately placed in the holder belonging to thecamera and covered with the dark slide. You then pass to the

THIRD OPERATION. --Submitting the Plate to the action of Light in theCamera. --Experience alone must guide the operator as to the time theplate should be exposed to the influence of the light; this beingdependent on a variety of circumstances, as clearness of theatmosphere--and here, a reference to the hygrometer will be ofadvantage--time of day, object to be taken, and the degree ofsensitiveness imparted to the plate by the quickstuff. As I havebefore said, the artist should be careful to see that the interior ofthe camera is clean and free from dust, as the small particles flyingabout, or set in motion by the sliding of the holder into the box, attach themselves to the plate, and cause the little black spots, bywhich an otherwise good picture is frequently spoiled. Care shouldalso be taken in withdrawing the dark slide, in front of the plate, from the holder, as the same effect may be produced by a too hastymovement. The lens is the last thing to be uncovered, by withdrawingthe cap c. Fig. 5. , which should not be done until you have placed thesitter in the most desirable position. When, according to the judgmentand experience of the operator, the plate has remained long enough toreceive a good impression, the cap is replaced over the lens, and thedark slide over the plate, which is then removed from the camera. 

Daguerreotypists generally mark time by their watches, arriving at thenearest possible period for producing a good picture by making severaltrials. As a ready method of marking short intervals of time is, however, a very important consideration, and as any instrument whichwill enable an artist to arrive at the exact period, must be animprovement, and worthy of universal adoption, I will here describe oneinvented by Mr. Constable of England, which he calls a

Sand Clock, or Time Keeper. --"It consists of a glass tube, about twelveinches long, by one in diameter, half filled with fine sand, similar tothat used for the ordinary minute glasses, and, like them, it has adiaphram, with a small hole in the centre through which the sand runs. The tube is attached to a board which revolves on a centre pin; on theside is a graduated scale, divided into half seconds; the tube is alsoprovided with a moveable index. This instrument is attached, in aconspicuous place, to the wall. The glass tube being revolved on itscentre, the index is set to the number of half seconds required, andthe sand running down, the required time is marked without thepossibility of error. In practice it will be found to be a far moreconvenient instrument for the purpose than either a clock or a secondswatch, and is applicable both for the camera and mercury box. "

If the artist finds it desirable or necessary to take the object to becopied in its right position, that is reverse the image on thespectrum, he can do so by attaching a mirror (which may be had of Mr. Anthony, or Mr. Roach) to the camera tube, at an angle of forty-fivedegrees. 

If, after taking the plate from the camera, it be examined, no picturewill yet be visible, but this is brought about by the

FOURTH PROCESS. --Bringing out the Picture, or rendering it Visible. --Wenow come to the use of the mercury bath, Fig. 11. To the bath athermometer is attached, to indicate the proper degree of beatrequired, which should never be raised above 170 deg. Fahrenheit. Theplate maybe put into one of the frames (see Fig. 11, ) over the mercury, face downwards, and examined from time to time, by simply raising itwith the fingers, or a pair of plyers. This operation, as well as theothers, should take place in the dark closet. 

[Illustration: Fig. 26 (hipho_26. Gif)]

[Updater's note: hipho_26. Gif and hipho27. Gif are both captioned Figure27. ]

Sometimes, to prevent the necessity of raising the plate, an additionalcover or top is made use of. It consists of a box fitted closely tothe inner rim of the bath, and having an inclined top (a, Fig. 27. ) Thetop is cut through and fitted with frames for each size of plate, likethose already described, and in the back is a piece of glass (b, )through which to view the progress of mercurialization, and anadditional piece (c, ) on one side, colored yellow, to admit the light. The outline only of the top is here given, in order to show everyportion of it at one view. 

The picture, being fully developed, is now taken out and examined; itmust not, however, be exposed to too strong a light. If any glaringdefects be perceived, it is better not to proceed with it, but place iton one side to be re-polished; if, on the contrary, it appears perfect, you may advance to the

FIFTH OPERATION. --Fixing the Image so that the light can no longer actupon it. --The following articles are required for this purpose:

Two or three porcelain or glass dishes, in form, something like fig. 24. 

A plate support, fig. 25. Few, I believe, now make use of this, although it is a very convenient article. 

Hyposulphite of Soda, A pair of Plyers. 

In Europe, they also use a drying apparatus, Fig. 27, but this, likethe plate support, is a matter of little consequence, and may bedispensed with. I will, however, describe it, for the benefit of thosewho may wish to use it. 

[Illustration: Fig. 27 (hipho_27. Gif)]

[Updater's note: hipho_26. Gif and hipho27. Gif are both captioned Figure27. ]

A vessel made of copper or brass, tinned inside, and large enough totake in the largest plate, but not more than half an inch wide, is themost convenient. It must be kept perfectly clean. Hot distilled wateris poured into it, and the temperature kept up by a spirit lamp. 

Hyposulphite of Soda. --Having made a solution of hyposulphite of soda, and well filtered it--the strength is immaterial; about half an ounceof the salt to a pint of distilled water is sufficient--pour it intoone of the porcelain dishes, put into another plain, and into a thirddistilled water. Immerse the plate with its face downwards into thehyposulphite, and the whole of the sensitive is removed, and the lighthas no farther action upon it; it is then to be removed from thehyposulphite and plunged into the plain water, or placed upon thesupport, fig. 25, and the water poured over it. It is then washed in asimilar manner with the distilled water and well examined, to see thatnot the slightest particle of dust rests on the surface. The next stepis to dry it. 

This may be readily accomplished by holding the plate with your plyers, and pouring distilled water over it--if it is hot, so much the better. Apply the spirit lamp to the back, at the corner held by the plyers, atthe same time facilitating the operation with the breath; pass the lampgradually downwards, finishing at the extreme corner. The last dropmay now be removed by a little bibulous paper. A single drop, even, ofdistilled water allowed to dry on any part of the surface, is certainto leave a stain which no after process can remove. 

To illustrate the necessity for having perfectly clean water, and freefrom all foreign matter--only to be avoided by using that which isdistilled--in these processes, I will relate a little anecdote. 

An operator in this city (New York) frequently made complaint to me, that his plates were occasionally very bad; coming out all over inlittle black and white spots and spoiling many very good pictures, regretting at the same time that perfect plates were not made, for hehad lost many customers in consequence of these defects. Thesecomplaints being somewhat periodical, I suggested that the fault mightbe in the hyposulphite, or chloride of gold solutions, or particles ofdust floating about in the room, and not in the plate. 

A few days after he stated, that his plates having served him again inthe same way, he procured a fresh supply of hyposulphite of soda andchloride of gold, but after applying them the result was no better. Hethen, by my advice, thoroughly cleaned his wash dishes, bottles andwater pail, made fresh solutions and had no further trouble, becomingsatisfied that the plates suffered an undue share of censure. 

SIXTH PROCESS. --Gilding the Picture. --This is an improvement the honorof which is due to M. Figeau, and may take place either before thedrying process, or at any subsequent period; but it improves thepicture so materially that it should never be neglected. The articlesnecessary for gilding are--

A Pair of Plyers; or a Gilding Stand (see fig. 19) and Chloride ofGold; or Hyposulphite of Gold. 

The latter is imported by Mr. E. Anthony, 205 Broadway, New York, andis decidedly the best article for the purpose. One bottle simplydissolved in a quart of water will make a very strong solution, andgives a richness to the picture impossible to be obtained from thechloride of gold. The process is precisely similar to that describedbelow for chloride of gold, taking care to cease the moment the bubblesare well defined over the surface of the plate. Many Daguerreotypists, after a superficial trial, discard the hyposulphite of gold asinferior; but I have no hesitation in asserting that the fault lieswith themselves; for in every case within my knowledge, where its usehas been persisted in until the correct method has been ascertained andthe nature of the gilding has become familiar, it is always preferred. In illustration of this fact I will relate an anecdote:

A gentleman to whom it had been recommended, purchased a bottle, andafter making one or two trials of it, wrote to his correspondent--"Sendme two bottles of chloride of gold, for I want no more of thehyposulphite; it is good for nothing. " A few weeks after he sent forthree bottles of the condemned article, confessing that he had foundfault unnecessarily; for, that since he had become familiar to its use, he must acknowledge its superiority, and would use no other gilding. 

The Solution of Chloride of Gold is prepared by dissolving in a pint ofdistilled water, fifteen grains of chrystalized chloride of gold. Thissolution will be of a yellow tint. In another pint of distilled waterdissolve fifty-five grains of hyposulphite of soda; pour gradually, invery small quantities, the gold into the hyposulphite of soda, stirringthe solution at intervals; when finished the mixture should be nearlycolorless. 

Place the plate on its stand, or hold it in the plyers, in a perfectlyhorizontal position--silver surface upward--having previously slightlyturned up the edges, so that it may hold the solution. Wet the surfacewith alcohol, letting any superfluous quantity drain off. The alcoholis of no farther use than to facilitate the flowing of the gold mixtureover the surface. Now pour on, carefully, as much of the preparationof gold as will remain on the plate. The under part of the plate isthen to be heated as uniformly as possible with the spirit lamp; smallbubbles will arise, and the appearance of the portrait or view verysensibly improved. The process must not be carried too far, but assoon as the bubbles disappear the lamp should be removed, and the plateimmersed in distilled water, and dried as before directed. 

7th. COLORING THE PICTURE. --I very much doubt the propriety of coloringthe daguerreotypes, as I am of opinion, that they are little, if any, improved by the operation, at least as it is now generally practised. 

There are several things requisite in an artist to enable him to colora head, or even a landscape effectively, and correctly, and I must saythat very few of these are possessed by our operators as a class. These requirements are, a talent for drawing--taste--due discriminationof effect--strict observance of the characteristic points in thefeatures of the subject--quick perception of the beautiful, and aknowledge of the art of mixing colors, and blending tints. 

The method now pursued, I do not hesitate to say, and have no fears ofbeing contradicted by those capable of critisizing is on the wholeruinous to any daguerreotype, and to a perfect one absolutelydisgusting. The day may come when accurate coloring may be obtained inthe camera. Until that day, if we cannot lead taste into the rightchannel, we will endeavor to give such instructions thatDaguerreotypists may proceed with this part of his work with a betterunderstanding of the principles involved. For this purpose I haveprepared a short chapter on the art of coloring, which may be found inthe latter part of this volume. 

To Preserve Daguerreotypes they must be well sealed and secured in acase, or frame. These, of course, are selected according to the tasteof the customer, the principal requisite being good glass. MostDaguerreotypists prefer the white French plate glass--and many think, very erroneously, that none is good unless it is thick--but the greatdesideratum is clearness and freedom from blisters; even glass a littletinged with green or yellow is to be preferred to the French plate whencloudy or blistered and there is very little of it comes to this marketthat is not so. It is to be hoped that some of our glass factorieswill manage to manufacture an article expressly for daguerreotypes; andI would recommend them to do so, for they would find it quite an itemof profit annually. 

Before enclosing the picture in the case you should be careful to wipethe glass perfectly clean, and blow from the picture any particles ofdust which may have fallen upon it. Then take strips of stickingpaper, about half or three quarters of an inch wide, and firmly andneatly secure it to the glass, having first placed a "mat" between themto prevent the plate being scratched by the glass. 

TO MAKE SEALING PAPER. --Dissolve one ounce of gum arabic, and a quarterof an ounce of gum tragicanth in a pint of water; then add ateaspoonful of benzoin. Spread this evenly on one side of good stouttissue paper; let it dry, and then cut it up in stripes, about half orthree quarters of an inch wide, for use. If it becomes too soft forsummer use, add gum arabic; if too hard and cracking, add benzoin orgum tragicanth; if it gets too thick, add water. 

COLORED DAGUERREOTYPES ON COPPER. --To effect this, take a polishedplate of copper and expose it to the vapor of iodine, or bromine, orthe two substances combined; or either of them in combination withchlorine. This gives a sensitive coating to the surface of the plate, which may then be submitted to the action of light in the camera. After remaining a sufficient time in the camera, the plate is taken outand exposed to the vapor of sulphuretted hydrogen. This vapor producesvarious colors on the plate, according to the intensity with which thelight has acted on the different parts; consequently a coloredphotographic picture is obtained. No further process is necessary asexposure to light does not effect the picture. 

By this process we have an advantage over the silvered plate, both ineconomy, and in the production of the picture in colors. 

INSTANTANEOUS PICTURES BY MEANS OF GALVANISM. --It will be seen by thefollowing valuable communication that galvanism can be successfullyapplied in producing pictures instantly; a process of great importancein securing the likeness of a child, or in taking views of animatednature. Colonel Whitney informs me that he once took a view of thesteeple of the St. Louis Court House after sundown by this means, andalso secured the image of a man in the act of stepping into a store, and before he had time to place his foot, raised for that purpose, onthe door step. Mr. Whitney is well known as the talented editor of theSunday Morning news. 

 New York, January 16, 1849. Mr. H. H. SNELLING. 

Dear Sir, --As you are about publishing a history of the Daguerreotype, and request a description of my mode of taking pictures instantaneouslyby the aid of galvanism, I comply with great pleasure. 

In the year 1841, while practicing the art in St. Louis, Mo. , I was attimes, during the summer, much troubled with the electric influence ofthe atmosphere, especially on the approach of a thunder-storm. At suchtimes I found the coating of my plates much more sensitive than whenthe atmosphere was comparatively free from the electric fluid, and theeffect was so irregular that no calculation could counteract thedifficulty. This satisfied me that electricity was in some measure animportant agent in the chemical process, and it occurred to me that theelement might be turned to advantage. I determined, therefore, toenter on a series of experiments to test my theory. Finding itimpossible to obtain an electric machine, and unwilling to abandon theexamination, it occurred to me, that the galvanic influence mightanswer the same purpose. I therefore proceeded to make a galvanicbattery in the following simple manner. I obtained a piece of zincabout two inches long, one inch wide, and an eighth of an inch thick. On this I soldered a narrow strip of copper, about six inches long, thesoldered end laid on one side of the zinc, and extending its wholelength. The battery was completed by placing the zinc in a glasstumbler, two-thirds full of dilute sulphuric acid, strong enough toproduce a free action of the metals. The upper end of the copper slipextending above the tumbler was sharpened to a point, and bent a littleover the glass. 

The method of using, was thus:--After preparing the plate in the usualmanner and placing it in the camera, in such manner as to expose theback of the plate to view, the battery was prepared by placing the zincin the acid, and as soon as the galvanic fluid began to traverse (ascould be known by the effervescence of the acid, operating on the zincand copper) the cap of the camera was removed, and the plate exposed tothe sitter; at the same instant the point of the battery was broughtquickly against the back of the plate, and the cap replaced instantly. If the plate is exposed more than an instant after the contact thepicture will generally be found solarized. By this process I havetaken pictures of persons in the act of walking, and in taking thepictures of infants and young children I found it very useful. 

 Very respectfully yours, THOMAS R. WHITNEY. 

CHAP. VII

PAPER DAGUERREOTYPES. --ETCHING DAGUERREOTYPES. 

Mr. Hunt describes a process, discovered by himself by which theDaguerrean art may be applied to paper. His description is asfollows:--

"Placing the paper on some hard body, wash it over on one side--bymeans of a very soft camel's hair pencil--with a solution of sixtygrains of bromide of potassium, in two fluid ounces of distilled water, and then dry it quickly by the fire. Being dry, it is again washedover with the same solution, and dried as before. A solution ofnitrate of silver--one hundred grains to an ounce of distilledwater--is to be applied over the same surface, and the paper quicklydried in the dark. In this state the papers may be kept for use. 

"When they are required, the above solution of silver is to beplentifully applied, and the paper placed wet in the camera, thegreatest care being taken that no day light--not even the faintestgleam--falls upon it until the moment when you are prepared, byremoving the dark slide, to permit the light, radiating from the objectyou wish to copy, to act in producing the picture. After a few secondsthe light must be again shut off, and the camera removed into a darkroom. " The necessity of removing the camera is now avoided by the useof the dark slide, already described, covering the picture in theholder, which alone may be removed. --Amer. Aut. 

"It will be found by taking the paper from the holder, that there isbut a very faint outline--if any--yet visible. Place it aside, inperfect darkness until quite dry; then place it in the mercurial vaporbox (meaning bath) and apply a very gentle heat to the bottom. Themoment the mercury vaporizes, the picture will begin to developeitself. The spirit lamp must now be removed for a short time, and whenthe action of the mercury appears to cease, it is to be very carefullyapplied again, until a well defined picture is visible. Thevaporization must then be suddenly stopped, and the photograph removedfrom the box. The drawing will then be very beautiful and distinct;but much detail is still clouded, for the developement of which it isonly necessary to place it in the dark and suffer it to remainundisturbed for some hours. There is now an inexpressible charm aboutthe pictures, equaling the delicate beauty of the daguerreotype; butbeing very susceptible of change, it must be viewed by the light of ataper only. The nitrate of silver must now be removed from the paper, by well washing it in soft water, to which a small quantity of salt hasbeen added, and it should afterwards be soaked in water only. When thepicture has been dried, wash it quickly over with a soft brush dippedin a warm solution of hyposulphite of soda, and then wash it for sometime in distilled water, in order that all the hyposulphite may beremoved. The drawing is now fixed and we may use it to procurepositive copies, (the original being termed a negative, ) many of whichmay be taken from one original. "

"The action of light on this preparation, does indeed appear to beinstantaneous. The exquisite delicacy of this preparation may beimagined, when I state that in five seconds in the camera, I have, during sunshine, obtained perfect pictures, and that when the sky isovercast, one minute is quite sufficient to produce a most decidedeffect. "

"This very beautiful process is not without its difficulties; and theauthor cannot promise that, even with the closest attention to theabove directions, annoying failures will not occur. It often happensthat some accidental circumstance--generally a projecting film or alittle dust--will occasion the mercurial vapor to act with great energyon one part of the paper, and blacken it before the other portions areat all effected. Again, the mercury will sometimes accumulate alongthe lines made by the brush, and give a streaky appearance to thepicture, although these lines are not at all evident before themercurial vapor was applied. (A brush sufficiently large--and they maybe easily obtained--will, in a measure, prevent this difficulty. --AmerAu. ) I have stated that the paper should be placed wet in the camera;the same paper may be used dry, which often is a great convenience. When in the dry state a little longer exposure is required; and insteadof taking a picture in four or five seconds, two or three minutes arenecessary. "

The durability of daguerreotypes has been, and is still, doubted bymany, but experiment has proved that they are more permanent than oilpaintings or engravings. 

ETCHING DAGUERREOTYPES. --There are several methods of accomplishingthis object; discovered and applied by different individuals. 

The first process was published at Vienna by Dr. Berres, and consistedin covering the plate with the mucilage of gum arabic, and thenimmersing the plate in nitric acid of different strengths. 

Mr. Figeau, of whom I have already spoken, likewise discovered aprocess for the engraving of Daguerreotypes; and founded on the beliefthat the lights of a Daguerreotype plate consists of unaltered silver, while the dark or shadows consists of mercury or an amalgam of mercurywith silver. He finds that a compound acid, consisting of a mixture ofnitric, nitrous, and muriatic acids, or of nitric mixed with nitrate ofpotass and common salt, has the property of attaching the silver inpresence of the mercury without acting upon the latter. Bi-chloride ofcopper answers the purpose also, but less completely. 

"When the clean surface of a Daguerreotype plate is exposed to theaction of this menstruum, particularly if warm, the white parts, orlights are not altered, but the dark parts are attacked, and chlorideof silver is formed, of which an insoluble coating is soon deposited, and the action of the acid soon ceases. This coat of chloride ofsilver is removed by a solution of ammonia, and then the acid appliedagain, and so on, until the depth of biting in is sufficient. However, it is not possible, by repeating this process, to get a sufficientforce of impression; a second operation is required, in order to obtainsuch a depth as will hold the ink, to give a dark impression; for thispurpose the whole plate is covered with drying oil; this is cleared offwith the hand, exactly in the way a copper plate printer cleans hisplate. The oil is thus left in the sinkings, or dark bitten in partsonly. The whole plate is now placed in a suitable apparatus, and thelights or prominent parts of the face are gilt by the electrotypeprocess. The whole surface is now touched with what the Frenchengravers call the "Resin Grain, " (grain de resine), a species ofpartial stopping out, and it is at once bitten in to a sufficient depthwith nitric acid, the gilding preserving the lights from all action ofthe acid. The resin grain gives a surface to the corroded partssuitable for holding the ink, and the plate is now finished and fit togive impressions resembling aquatint. But as silver is so soft a metalthat the surface of the plate might be expected to wear rapidly, thediscoverer proposes to shield it by depositing over its whole surface avery thin coat of copper by the electrotype process; which when wornmay be removed at pleasure down to the surface of the noble metalbeneath, and again a fresh coat of copper deposited; and so anunlimited number of impressions obtained without injuring the plateitself. "

If, as has been asserted, steel may be rendered sufficiently sensitive, to take photographic impressions, to what a revolution will the art ofengraving be subject by the discovery of this process. 

CHAP. VIII. 

PHOTOGENIC DRAWING ON PAPER. 

We shall now proceed to describe the various processes for Photogenicdrawing on paper; first, however, impressing on the mind of theexperimenter, the necessity which exists for extreme care in everystage of the manipulation. In this portion of my work I am entirelyindebted to the works of Professors Hunt, Fisher and others. 

I. APPARATUS AND MATERIALS. --Paper. --The principal difficulty to becontended with in using paper, is the different power of imbibitionwhich we often find possessed in the same sheet, owing to triflinginequalities in its texture. This is, to a certain extent, to beovercome by a careful examination of each sheet, by the light of acandle or lamp at night, or in the dark. By extending each sheetbetween the light and the eye, and slowly moving it up and down, andfrom left to right, the variations in its texture will be seen by thedifferent quantities of light which pass through it in different parts;and it is always the safest course to reject every sheet in whichinequalities exist. Paper sometimes contains minute portions ofthread, black or brown specks, and other imperfections, all of whichmaterially interfere with the process. Some paper has an artificialsubstance given to it by sulphate of lime (Plaster of Paris); thisdefect only exists, however, in the cheaper sorts of demy, andtherefore can be easily avoided. In all cases such paper should berejected, as no really sensitive material can be obtained with it. Paper-makers, as is well known, often affix their name to one half thesheet; this moiety should also be placed aside, as the letters mustfrequently come out with annoying distinctness. Well sized paper is byno means objectionable, indeed, is rather to be preferred, since thesize tends to exalt the sensitive powers of the silver. The principalthing to be avoided, is the absorption of the sensitive solution intothe pores; and it must be evident that this desideratum cannot beobtained by unsized paper. Taking all things into consideration, thepaper known as satin post would appear to be preferable, although theprecautions already recommended should be taken in its selection. 

Brushes. --The necessary solutions are to be laid upon the paper bybrushes. Some persons pass the paper over the surface of thesolutions, thus licking up, as it were, a portion of the fluid; butthis method is apt to give an uneven surface; it also rapidly spoilsthe solutions. At all events, the brush is the most ready and the mosteffectual means. 

Distilled Water. --All the water used, both for mixing the solutions, washing the paper, or cleaning the brushes, must be distilled, toobtain good results, for reasons before specified. 

Blotting Paper. --In many instances, the prepared paper requires to belightly dried with bibulous paper. The best description is the whitesort. In each stage of the preparation distinct portions of bibulouspaper must be used. If these be kept seperate and marked, they can beagain employed for the same stage; but it would not do, for example, todry the finished picture in the same folds in which the sensitive paperhad been pressed. A very convenient method is to have two or threequarto size books of bibulous paper, one for each seperate process. 

Nitrate of Silver. --In the practice of the photographic art, muchdepends on the nitrate of silver. Care should be taken to procure thebest; the crystalized salt is most suitable for the purpose. While inthe form of crystal it is not injured by exposure to light, but thebottles containing the solutions of this salt should at all times bekept wrapped in dark paper, and excluded from daylight. 

II. DIFFERENT METHODS OF PREPARING THE PAPER. --Preparation of thePaper. --Dip the paper to be prepared into a weak solution of commonsalt. The solution should not be saturated, but six or eight timesdiluted with water. When perfectly moistened, wipe it dry with atowel, or press it between bibulous paper, by which operation the saltis uniformly dispersed through its substance. Then brush over it, onone side only, a solution of nitrate of silver. The strength of thissolution must vary according to the color and sensitiveness required. Mr. Talbot recommends about fifty grains of the salt to an ounce ofdistilled water. Some advise twenty grains only, while others sayeighty grains to the ounce. When dried in a dark room, the paper isfit for use. To render this paper still more sensitive, it must againbe washed with salt and water, and afterwards with the same solution ofnitrate of silver, drying it between times. This paper, if carefullymade, is very useful for all ordinary photographic purposes. Forexample, nothing can be more perfect than the images it gives of leavesand flowers, especially with a summer's sun; the light, passing throughthe leaves, delineates every ramification of their fibres. Inconducting this operation, however, it will be found that the resultsare sometimes more and sometimes less satisfactory, in consequence ofsmall and accidental variations in the proportions employed. Ithappens sometimes that the chloride of silver formed on the surface ofthe paper is disposed to blacken of itself, without any exposure tolight. This shows that the attempt to give it sensibility has beencarried too far. The object is, to approach as nearly to thiscondition as possible without reaching it; so that the preparation maybe in a state ready to yield to the slightest extraneous force, such asthe feeblest effect of light. 

Cooper's Method. --Soak the paper in a boiling hot solution of chlorateof potash (the strength matters not) for a few minutes; then take itout, dry it, and wet it with a brush, on one side only, dipped in asolution of nitrate of silver, sixty grains to an ounce of distilledwater, or, if not required to be so sensitive, thirty grains to theounce will do. This paper possesses a great advantage over any other, for the image can be fixed by mere washing. It is, however, very aptto become discolored even in the washing, or shortly afterwards, andis, besides, not so sensitive, nor does it become so dark as that madeaccording to Mr. Talbot's method. 

Daguerre's Method. --Immerse the paper in hydrochloric (or as it is morecommonly called, muriatic) ether, which has been kept sufficiently longto become acid; the paper is then carefully and completely dried, asthis is essential to its proper preparation. It is then dipped into asolution of nitrate of silver, and dried without artificial heat in aroom from which every ray of light is carefully excluded. By thisprocess it acquires a very remarkable facility in being blackened on avery slight exposure to light, even when the latter is by no meansintense. The paper, however, rapidly loses its extreme sensitivenessto light, and finally becomes no more impressionable by the solar beamsthan common nitrate paper. 

Bromide Paper. --Of all common photographic paper, the best, because theleast troublesome in making, and the most satisfactory in result, isthat which is termed bromine paper, and which is thusprepared:--Dissolve one hundred grains of bromide of potassium in oneounce of distilled water, and soak the paper in this solution. Takeoff the superfluous moisture, by means of your bibulous paper, and whennearly dry, brush it over on one side only, with a solution of onehundred grains of nitrate of silver to an ounce of distilled water. The paper should then be dried in a dark room, and, if required to bevery sensitive, should a second time be brushed over with the nitrateof silver solution. 

In preparing the papers mentioned above, there are two circumstanceswhich require particular attention. In the first place, it isnecessary to mark the paper on the side spread with the solutions ofnitrate of silver, near one of the extreme corners. This answers twopurposes: in the first place it serves to inform the experimentalistof the sensitive surface; and secondly, it will be a guide as to whichportion of the papers has been handled during the application of thesolution, as the impress of the fingers will probably come out upon thephotograph. The second caution is, that the application of thesensitive solution (nitrate of silver, ) and the subsequent drying ofthe paper, must be always conducted in a perfectly dark room, the lightof a candle alone being used. 

[Illustration: Fig. 29 (hipho_29. Gif)]

III. PHOTOGENIC PROCESS ON PAPER. --Method. --The simplest mode is toprocure a flat board and a square of glass, larger in size than theobject intended to be copied. On the board place the photographicpaper with the prepared side upwards, and upon it the object to becopied; over both lay the glass and secure them so that they are inclose connection by means of binding screws or clamps, similar to g. G. Fig. 29. Should the object to be copied be of unequal thickness, suchas a leaf, grass, &c. , it will be necessary to place on the board, first, a soft cushion, which may be made of a piece of fine flannel andcotton wool. By this means the object is brought into closer contactwith the paper, which is of great consequence, and adds materially tothe clearness of the copy. The paper is now exposed to diffuseddaylight, or, still better, to the direct rays of the sun, when thatpart of the paper not covered by the object will become tinged with aviolet color, and if the paper be well prepared, it will in a shorttime pass to a deep brown or bronze color. It must then be removed, asno advantage will be obtained by keeping it longer exposed; on thecontrary, the delicate parts yet uncolored will become in some degreeaffected. The photogenic paper will now show a more or less white anddistinct representation of the object. The apparatus figured at 29consists of a wooden frame similar to a picture frame; a piece of plateglass is fixed in front; and it is provided with a sliding cover ofwood, c. , which is removed when the paper is ready to be exposed to theaction of the light. The back, d. , which is furnished with a cushion, as just described, is made to remove for the purpose of introducing theobject to be copied, and upon it the prepared paper; the back is thenreplaced, and, by aid of the cross piece and screw, e. , the whole isbrought into close contact with the glass. 

The objects best delineated on these photographic papers, are lace, feathers, dried plants, particularly the ferns, sea-weeds and the lightgrasses, impressions of copper plate and wood engravings, particularlyif they have considerable contrast of light and shade--(these should beplaced with the face downwards, having been previously prepared ashereafter directed)--paintings on glass, etchings, &c. 

To fix the Drawings. --Mr. Talbot recommends that the drawings should bedipped in salt and water, and in many instances this method willsucceed, but at times it is equally unsuccessful. Iodide of potassium, or, as it is frequently called, hydriodate of potash, dissolved inwater, and very much diluted, (twenty-five grains to one ounce ofwater, ) is a more useful preparation to wash the drawings with; it mustbe used very weak or it will not dissolve the unchanged muriate only, as is intended but the black oxide also, and the drawing be therebyspoiled. 

But the most certain material to be used is the hyposulphite of soda. One ounce of this salt should be dissolved in about a pint of distilledwater. Having previously washed the drawing in a little lukewarmwater, which of itself removes a large portion of the muriate of silverwhich is to be got rid of, it should be dipped once or twice in thehyposulphite solution. By this operation the muriate which lies uponthe lighter parts will become so altered in its nature as to beunchanged by light, while the rest remains dark as before. 

It will be evident from the nature of the process, that the lights andshadows of an object are reversed. That which is originally opaquewill intercept the light, and consequently those parts of thephotogenic paper will be least influenced by light, while any part ofthe object which is transparent, by admitting the light through it, will suffer the effect to be greater or less in exact proportion to itsdegree of transparency. The object wholly intercepting the light willshow a white impression; in selecting, for example, a butterfly for anobject, the insect, being more or less transparent, leaves aproportionate gradation of light and shade, the most opaque partsshowing the whitest. It may be said, therefore, that this is notnatural, and in order to obtain a true picture--or, as it is termed, apositive picture--we must place our first acquired photograph upon asecond piece of photogenic paper. Before we do this, however, we mustrender our photograph transparent, otherwise the opacity of the paperwill mar our efforts. 

To accomplish this object, the back of the paper containing thenegative, or first acquired photograph, should be covered with white orvirgin wax. This may be done by scraping the wax upon the paper, andthen, after placing it between two other pieces of paper, passing aheated iron over it. The picture, being thus rendered transparent, should now be applied to a second piece of photogenic paper, andexposed, in the manner before directed, either to diffused day-light orto the direct rays of the sun. The light will now penetrate the whiteparts, and the second photograph be the reverse of the first, or a truepicture of the original. 

Instead of wax, boiled linseed oil--it must be the best and mosttransparent kind--may be used. The back of the negative photographshould be smeared with the oil, and then placed between sheets ofbibulous paper. When dry the paper is highly transparent. 

IV. APPLICATION OF PHOTOGENIC DRAWING. --This method of photogenicdrawing may be applied to useful purposes, such as the copying ofpaintings on glass by the light thrown through them on the preparedpaper--Imitations of etchings, which may be accomplished by covering apiece of glass with a thick coat of white oil paint; when dry, with thepoint of a needle, lines or scratches are to be made through the whitelead ground, so as to lay the glass bare; then place the glass upon apiece of prepared paper, and expose it to the light. Of course everyline will be represented beneath of a black color, and thus animitation etching will be produced. It is also applicable to thedelineation of microscopic objects, architecture, sculpture, landscapesand external nature. 

A novel application of this art has been recently suggested, whichwould doubtless prove useful in very many instances. By rendering thewood used for engravings sensitive to light, impressions may be at oncemade thereon, without the aid of the artist's pencil. The preparationof the wood is simply as follows:--Place its face or smooth sidedownwards, in a plate containing twenty grains of common salt dissolvedin an ounce of water; here let it remain for five minutes, take it outand dry it; then place it again face downwards in another platecontaining sixty grains of nitrate of silver to an ounce of water; herelet it rest one minute, when taken out and dried in the dark it will befit for use, and will become, on exposure to the light, of a fine browncolor. Should it be required more sensitive, it must be immersed ineach solution a second time, for a few seconds only. It will now bevery soon effected by a very diffused light. 

This process may be useful to carvers and wood engravers not only tothose who cut the fine objects of artistical design, but still more tothose who cut patterns and blocks for lace, muslin, calico-printing, paper hangings, etc. , as by this means the errors, expense and time ofthe draughtsman may be wholly saved, and in a minute or two the mostelaborate picture or design, or the most complicated machinery, bedelineated with the utmost truth and clearness. 

CHAP. IX. 

CALOTYPE AND CHRYSOTYPE. 

The materials and apparatus necessary for the Calotype process are--

Two or Three Shallow Dishes, for holding distilled water, iodide, potassium, &c. --the same water never being used for two differentoperations. 

White Bibulous Paper. 

Photogenic Camera--Fig. 9. 

Pressure Frame--Fig 29. 

Paper, of the very best quality--directions for the choice of whichhave been already given. 

A Screen of Yellow Glass. 

Camels' or Badgers' hair Brushes:--A seperate one being kept for eachwash and solution, and which should be thoroughly cleansed immediatelyafter using in distilled water. That used for the gallo-nitrate issoon destroyed, owing to the rapid decomposition of that preparation. 

A Graduated Measure. 

Three or Four Flat Boards, to which the paper may be fixed with drawingpins. 

A Hot Water Drying Apparatus, for drying the paper will also be founduseful. 

In preparing the Calotype paper, it is necessary to be extremelycareful, not only to prevent the daylight from impringing upon it, butalso to exclude, if possible, the strong glare of the candle or lamp. This may be effected by using a shade of yellow glass or gauze, whichmust be placed around the light. Light passing through such a mediumwill scarcely affect the sensitive compounds, the yellow glassintercepting the chemical rays. 

Preparation of the Iodized Paper. --Dissolve one hundred grains ofcrystalized nitrate of silver in six ounces of distilled water, andhaving fixed the paper to one of the boards, brush it over with a softbrush on one side only with this solution, a mark being placed on thatside whereby it may be known. When nearly dry dip it into a solutionof iodide of potassium, containing five hundred grains of that saltdissolved in a pint of water. When perfectly saturated with thissolution, it should be washed in distilled water, drained and allowedto dry. This is the first part of the process, and the paper soprepared is called iodized paper. It should be kept in a port-folio ordrawer until required: with this care it may be preserved for anylength of time without spoiling or undergoing any change. 

Mr. Cundell finds a stronger solution of nitrate of silver preferable, and employs thirty grains to the ounce of distilled water: he also addsfifty grains of common salt to the iodide of potassium, which heapplies to the marked side of the paper only. This is the firstprocess. 

Preparation of the paper for the Camera. --The second process consistsin applying to the above a solution which has been named by Mr. Talbotthe "Gallo-Nitrate of Silver;" it is prepared in the following manner:Dissolve one hundred grains of crystalized nitrate of silver in twoounces of distilled water, to which is added two and two-third drachmsof strong acetic acid. This solution should be kept in a bottlecarefully excluded from the light. Now, make a solution of gallic acidin cold distilled water: the quantity dissolved is very small. Whenit is required to take a picture, the two liquids above describedshould be mixed together in equal quantities; but as it speedilyundergoes decomposition, and will not keep good for many minutes, onlyjust sufficient for the time should be prepared, and that used withoutdelay. It is also well not to make much of the gallic acid solution, as it will not keep for more than a few days without spoiling. A sheetof the iodized paper should be washed over with a brush with this mixedsolution, care being taken that it be applied to the marked side. Thisoperation must be performed by candle light. Let the paper rest half aminute, then dip it into one of the dishes of water, passing it beneaththe surface several times; it is now allowed to drain, and dried byplacing its marked side upwards, on the drying apparatus. It is betternot to touch the surface with bibulous paper. It is now highlysensitive, and ready to receive the impression. In practice it isfound better and more economical not to mix the nitrate of silver andgallic acid, but only to brush the paper with the solution of thenitrate. 

Mr. Talbot has recently proposed some modifications in his method ofpreparing the calotype paper. The paper is first iodized in the usualway; it is then washed over with a saturated solution of gallic acid indistilled water and dried. Thus prepared he calls it the io-gallicpaper: it will remain good for a considerable time if kept in a pressor portfolio. When required for use, it is washed with a solution ofnitrate of silver (fifty grains to the ounce of distilled water), andit is then fit for the camera. 

Exposure in the Camera. --The calotype paper thus prepared possesses avery high degree of sensibility when exposed to light, and we are thusprovided with a medium by which, with the aid of the photogenic camera, we may effectually copy views from nature, figures, buildings, and eventake portraits from the shadows thrown on the paper by the living face. The paper may be used somewhat damp. The best plan for fixing it inthe camera is to place it between a piece of plate glass and some othermaterial with a flat surface, as a piece of smooth slate or an ironplate, which latter, if made warm, renders the paper more sensitive, and consequently the picture is obtained more rapidly. 

Time of Exposure. --With regard to the time which should be allowed forthe paper to remain in the camera, no direct rules can be laid down;this will depend altogether upon the nature of the object to be copied, and the light which prevails. All that can be said is, that the timenecessary for forming a good picture varies from thirty seconds to fiveminutes, and it will be naturally the first object of the operator togain by experience this important knowledge. 

Bringing Out the Picture. --The paper when taken from the camera, whichshould be done so as to exclude every ray of light--and here the darkslide of the camera plate holder becomes of great use--bears noresemblance to the picture which in reality is formed. The impressionis latent and invisible, and its existence would not be suspected byany one not acquainted with the process by previous experiment. Themethod of bringing out the image is very simple. It consists inwashing the paper with the gallo-nitrate of silver, prepared in the wayalready described, and then warming it gently, being careful at thesame time not to let any portion become perfectly dry. In a fewseconds the part of the paper upon which the light has acted will beginto darken, and finally grow entirely black, while the other partsretain their original color. Even a weak impression may be brought outby again washing the paper in the gallo-nitrate, and once more gentlywarming it. When the paper is quite black, as is generally the case, it is a highly curious and beautiful phenomenon to witness thecommencement of the picture, first tracing out the stronger outlines, and then gradually filling up all the numerous and complicated details. The artist should watch the picture as it developes itself, and when inhis judgment it has attained the greatest degree of strength andclearness, he shall stop further proceedings by washing it with thefixing liquid. Here again the mixed solution need not be used, but thepicture simply brushed over with the gallic acid. 

The Fixing Process. --In order to fix the picture thus obtained, firstdip it into water; then partly dry it with bibulous paper, and wash itwith a solution of bromide of potassium--containing one hundred grainsof that salt dissolved in eight or ten ounces of distilled water. Thepicture is again washed with distilled water, and then finally dried. Instead of bromide of potassium, a solution of hyposulphite of soda, asbefore directed, may be used with equal advantage. 

The original calotype picture, like the photographic one described inthe last chapter, is negative, that is to say, it has its lights andshades reversed, giving the whole an appearance not conformable tonature. But it is easy from this picture to obtain another which shallbe conformable to nature; viz. , in which the lights shall berepresented by lights, and the shades by shades. It is only necessaryto take a sheet of photographic paper (the bromide paper is the best), and place it in contact with a calotype picture previously renderedtransparent by wax or oil as before directed. Fix it in the frame, Fig. 29, expose it in the sunshine for a short time, and an image orcopy will be formed on the photogenic paper. The calotype paper itselfmay be used to take the second, or positive, picture, but this Mr. Talbot does not recommend, for although it takes a much longer time totake a copy on the photogenic paper, yet the tints of such copy aregenerally more harmonious and agreeable. After a calotype picture hasfurnished a number of copies it sometimes grows faint, and thesubsequent copies are inferior. This may be prevented by means of aprocess which revives the strength of the calotype pictures. In orderto do this, it is only necessary to wash them by candlelight withgallo-nitrate of silver, and then warm them. This causes all theshades of the picture to darken considerably, while the white parts areunaffected. After this the picture is of course to be fixed a secondtime. It will then yield a second series of copies, and, in this way, a great number may frequently be made. 

The calotype pictures when prepared as we have stated, possess ayellowish tint, which impedes the process of taking copies from them. In order to remedy this defect, Mr. Talbot has devised the followingmethod. The calotype picture is plunged into a solution consisting ofhyposulphite of soda dissolved in about ten times its weight of water, and heated nearly to the boiling point. The picture should remain inabout ten minutes; it must then be removed, washed and dried. By thisprocess the picture is rendered more transparent, and its lights becomewhiter. It is also rendered exceedingly permanent. After this processthe picture may be waxed, and thus its transparency increased. Thisprocess is applicable to all photographic papers prepared withsolutions of silver. 

Having thus fully, and it is hoped clearly, considered the process, itmay be necessary before dismissing the calotype from notice, to add oneor two remarks from the observations and labors of some who haveexperimented in this art. Dr. Ryan in his lectures before the RoyalPolytechnic Institution, has observed, that in the iodizing process thesensitiveness of the paper is materially injured by keeping it too longin the solution of iodide of potassium, owing to the newly formediodide of silver being so exceedingly solvable in excess of iodide ofpotassium as in a few minutes to be completely removed. The papershould be dipped in the solution and instantly removed. There isanother point, too, in the preparation of the iodized paper in whichsuggestions for a slight deviation from Mr. Talbot's plan have beenmade. In the first instance, it is recommended that the paper bebrushed over with the iodide of potassium, instead of the nitrate ofsilver, transposing, in fact, the application of the first twosolutions. The paper, having been brushed over with the iodide ofpotassium in solution, is washed in distilled water and dried. It isthen brushed over with nitrate of silver, and after drying is dippedfor, a moment in a fresh solution of iodide of potassium of onlyone-fourth the strength of the first, that is to say, one hundred andtwenty-five grains of the salt to a pint of water. After this it isagain washed and dried. The advantage derived from this method, is amore sensitive paper, and a more even distribution of the compoundsover the surface. 

Another deviation from Mr. Talbot's method has been suggested, asfollows:

Brush the paper over with a solution of one hundred grains of nitrateof silver to an ounce of water. When nearly, but not quite, dry, dipit into a solution of twenty-five grains of iodide of potassium to oneounce of distilled water, drain it, wash it in distilled water andagain drain it. Now brush it over with aceto-nitrate of silver, madeby dissolving fifty grains of nitrate of silver in one ounce ofdistilled water, to which is added one sixth of its volume of strongacetic acid. Dry it with bibulous paper, and it is ready for receivingthe image. When the impression has been received, which will requirefrom one to five minutes according to the state of the weather, it mustbe washed with a saturated solution of gallic acid to which a few dropsof the aceto-nitrate of silver, made as above, have been added. Theimage will thus be gradually brought out, and may be fixed withhyposulphite of soda. To obtain the positive picture, paper must beused brushed over with an ammonio-nitrate of silver, made thus: fortygrains of nitrate of silver is to be dissolved in one ounce ofdistilled water, and liquid ammonia cautiously added till itre-dissolves the precipitate. 

A pleasing effect may be given to calotype, or indeed to allphotographic pictures, by waxing them at the back, and mounting them onwhite paper, or if colored paper be used, various beautiful tones ofcolor are produced. 

POSITIVE CALOTYPE. 

At a meeting of the British Association, Professor Grove described aprocess by which positive calotype pictures could be directly obtained;and thus the necessity to transfer by which the imperfections of thepaper are shown, and which is moreover a troublesome and tediousprocess, is avoided. As light favors most chemical actions, Mr. Grovewas led to believe that a paper darkened by the sun (which darkening issupposed to result from the precipitation of silver) might be bleachedby using a solvent which would not attack the silver in the dark, butwould do so in the light. The plan found to be the most successful isas follows: ordinary calotype paper is darkened till it assumes a deepbrown color, almost amounting to black; it is then redipped into theordinary solution of iodide of potassium, and dried. When required foruse it is drawn over dilute nitric acid--one part acid to two and ahalf parts water. In this state, those parts exposed to the light arerapidly bleached, while the parts not exposed remain unchanged. It isfixed by washing in water, and subsequently in hyposulphite of soda, orbromide of potassium. 

Mr. Grove also describes a process for converting a negative calotypeinto a positive one, which promises, when carried out, to be of greatutility. 

Let an ordinary calotype image or portrait be taken in the camera, anddeveloped by gallic acid; then drawn over iodide of potassium anddilute nitric acid and exposed to full sunshine; while bleaching thedark parts, the light is redarkening the newly precipitated iodide inthe lighter portions and thus the negative picture is converted into apositive one. 

The calotype process has been applied to the art of printing, inEngland, but it possesses no advantages whatever over the method, withtype, now so gloriously brought to perfection; and I can hardly thinkit will ever be made of any utility. For the benefit of the curious, however, I will give Mr. Talbot's method. 

Some pages of letter-press are taken printed on one side only; andwaxed, to render them more transparent; the letters are then cut outand sorted. To compose a new page lines are ruled on a sheet of whitepaper, and the words are formed by fixing the seperate letters in theirproper order. The page being ready, a negative photograph is producedfrom it, from which the requisite number of positive photogenic copiesmay be obtained. 

Another method, which requires the use of the camera, consists inemploying large letters painted on rectangular pieces of wood, coloredwhite. These are arranged in lines on a tablet or board, by slippingthem into grooves which keep them steady and upright, thus forming apage on an enlarged scale. It is now placed before a camera, and areduced image of it of the required size is thrown upon the sensitivepaper. The adjustments must be kept invariable, so that theconsecutive pages may not vary from one another in the size of thetype. Mr. Talbot has patented his process, but what benefit he expectsto derive from it, I am at a loss to determine. 

Enlarged copies of calotype or Daguerreotype portraits may be obtainedby throwing magnified images of them, by means of lenses, upon calotypepaper. 

THE CHRYSOTYPE. 

A modification of Mr. Talbot's process, to which the name of Chrysotypewas given by its discoverer, Sir John Herschel, was communicated inJune 1843 to the Royal Society, by that distinguished philosopher. This modification would appear to unite the simplicity of photographywith all the distinctness and clearness of calotype. This preparationis as follows. 

The paper is to be washed in a solution of ammonio-citrate of iron; itmust then be dried, and subsequently brushed over with a solution ofthe ferro-sesquicyanuret of potassium. This paper, when dried in aperfectly dark room, is ready for use in the same manner as ifotherwise prepared, the image being subsequently brought out by anyneutral solution of gold. Such was the first declaration of hisdiscovery, but he has since found that a neutral solution of silver isequally useful in bringing out the picture. Photographic picturestaken on this paper are distinguished by a clearness of outline foreignto all other methods. 

CHAP. X. 

CYANOTYPE--ENERGIATYPE--CHROMATYPE--ANTHOTYPE--AMPHITYPE AND "CRAYONDAGUERREOTYPE. "

The several processes enumerated at the head of this chapter, are alldiscoveries of English philosophers, with the exception of the thirdand last named. Anthotype was first attempted by M. Ponton a Frenchsavan, although it was reserved to Mr. Hunt to bring the process to itspresent state. The "Crayon Daguerreotype" is an improvement made by J. A Whipple, Esq. , of Boston. 

I. CYANOTYPE. 

So called from the circumstance of cyanogen in its combinations withiron performing a leading part in the process. It was discovered bySir John Herschel. The process is a simple one, and the resultingpictures are blue. 

Brush the paper over with a solution of the ammonio-citrate of iron. This solution should be sufficiently strong to resemble sherry wine incolor. Expose the paper in the usual way, and pass over it verysparingly and evenly a wash of the common yellow ferro-cyanate ofpotass. As soon as the liquid is applied, the negative picturevanishes, and is replaced by a positive one, of a violet blue color, ona greenish yellow ground, which at a certain time possesses a highdegree of sharpness, and singular beauty of tint. 

A curious process was discovered by Sir John Herschel, by which dormantpictures are produced capable of developement by the breath, or bykeeping in a moist atmosphere. It is as follows. 

If nitrate of silver, specific gravity 1. 200 be added to ferro-tartaricacid, specific gravity 1. 023, a precipitate falls, which is in a greatmeasure redissolved by a gentle heat, leaving a black sediment, which, being cleared by subsidence, a liquid of a pale yellow color isobtained, in which the further addition of the nitrate causes noturbidness. When the total quantity of the nitrated solution addedamounts to about half the bulk of the ferro-tartaric acid, it isenough. The liquid so prepared does not alter if kept in the dark. Spread on paper, and exposed wet to the sunshine (partly shaded) for afew seconds, no impression seems to be made, but by degrees, althoughwithdrawn from the action of light, it developes itself spontaneously, and at length becomes very intense. But if the paper be thoroughlydried in the dark, (in which state it is of a very pale greenish yellowcolor, ) it possesses the singular property of receiving a dormant orinvisible picture, to produce which from thirty to sixty seconds'exposure to sunshine is requisite. It should not be exposed too long, as not only is the ultimate effect less striking, but a picture beginsto be visibly produced, which darkens spontaneously after it iswithdrawn. But if the exposure be discontinued before this effectcomes on, an invisible impression is the result, to develope which allthat is necessary is to breathe upon it, when it immediately appears, and very speedily acquires an extraordinary intensity and sharpness, asif by magic. Instead of the breath, it may be subject to the regularaction of aqueous vapor, by laying it in a blotting paper book, ofwhich some of the outer leaves on both sides have been dampened, or byholding over warm water. 

II. ENERGIATYPE. 

Under this title a process has been brought forward by Mr. Hunt. Itconsists of the application of a solution of succinic acid to paper, which is subsequently washed over with nitrate of silver. The image isthen to be taken either in the camera or otherwise, as required, and isbrought out by the application of the sulphate of iron in solution. Although this process has not come into general use, its exactdescription may be interesting to the general reader, and we thereforesubjoin it. 

The solution with which the paper is first washed is to be prepared asfollows: succinic acid, two drachms; common salt, five grains;mucilage of gum arabic, half a fluid drachm; distilled water, one fluiddrachm and a half. When the paper is nearly dry, it is to be brushedover with a solution of nitrate of silver, containing a drachm of thesalt, to an ounce of distilled water. It is now ready for exposure inthe camera. To bring out the dormant picture it is necessary to washit with a mixture of a drachm of concentrated solution of the greensulphate of iron and two drachms and a half of mucilage of gum arabic. 

Subsequently, however, it has been found that the sulphate of ironproduces upon all the salts of silver effects quite as beautiful as inthe succinate. On the iodide, bromide, acetate, and benzoate, theeffects are far more pleasing and striking. When pictures areproduced, or the dormant camera image brought out, by the agency ofsulphate of iron, it is remarkable how rapidly the effect takes place. Engravings can be thus copied almost instantaneously, and camera viewsobtained in one or two minutes on almost any preparation of silver. The common sulphate of copper solution has the same property. 

III. CHROMATYPE. 

Many efforts have been made to render chromatic acid an active agent inthe production of photographs. M. Ponton used a paper saturated withbichromate of potash, and this was one of the earliest photogenicprocesses. M. Becquerel improved upon this process by sizing the paperwith starch previous to the application of the bichromate of potashsolution, which enabled him to convert the negative picture into apositive one, by the use of a solution of iodine, which combined withthat portion of the starch on which the light had not acted. But byneither of these processes could clear and distinct pictures be formed. Mr. Hunt has, however, discovered a process which is so exceedinglysimple, and the resulting pictures of so pleasing a character, that, although it is not sufficiently sensitive for use in the camera, itwill be found of the greatest value for copying botanical specimens, engravings, or the like. 

The paper to be prepared is washed over with a solution of sulphate ofcopper--about one drachm to an ounce of water--and partially dried; itis then washed with a moderately strong solution of bichromate ofpotash, and dried at a little distance from the fire. Paper thusprepared may be kept any length of time, in a portfolio, and are alwaysready for use. 

When exposed to the sunshine for a time, varying with the intensity ofthe light, from five to fifteen or twenty minutes, the result isgenerally a negative picture. It is now to be washed over with asolution of nitrate of silver, which immediately produces a verybeautiful deep orange picture upon a light dim colored, or sometimesperfectly white ground. This picture must be quickly fixed, by beingwashed in pure water, and dried. With regard to the strength of thesolutions, it is a remarkable fact, that, if saturated solutions beemployed, a negative picture is first produced, but if the solutions bethree or four times their bulk of water, the first action of the sun'srays darkens the picture, and then a very bleaching effect follows, giving an exceedingly faint positive picture, which is brought out withgreat delicacy by the silver solution. 

It is necessary that pure water should be used for the fixing, as thepresence of any muriate damages the picture, and here arises anotherpleasing variation of the Chromatype. If the positive picture beplaced in a very weak solution of common salt the image slowly fadesout, leaving a faint negative outline. If it now be removed from thesaline solution, dried, and again exposed to sunshine, a positivepicture of a lilac color will be produced by a few minutes exposure. Several other of the chromates may be used in this process, but none isso successful as the chromate of copper. 

IV. ANTHOTYPE. 

The expressed juice, alcoholic, or watery infusion of flowers, orvegetable substances, may be made the media of photogenic action. Thisfact was first discovered by Sir John Herschel. We have already givena few examples of this in the third chapter. 

Certain precautions are necessary in extracting the coloring matter offlowers. The petals of fresh flowers are carefully selected, andcrushed to a pulp in a marble mortar, either alone or with the additionof a little alcohol, and the juice expressed by squeezing the pulp in aclean linen or cotton cloth. It is then to be spread upon paper with aflat brush, and dried in the air without artificial heat. If alcoholbe not added, the application on paper must be performed immediately, as the air (even in a few minutes), irrecoverably changes or destroystheir color. If alcohol be present this change is much retarded, andin some cases is entirely prevented. 

Most flowers give out their coloring matter to alcohol or water. Some, however, refuse to do so, and require the addition of alkalies, othersof acid, &c. Alcohol has, however, been found to enfeeble, and in manycases to discharge altogether these colors; but they are, in mostcases, restored upon drying, when spread over paper. Papers tingedwith vegetable colors must always be kept in the dark, and perfectlydry. 

The color of a flower is by no means always, or usually, that which itsexpressed juice imparts to white paper. Sir John Herschel attributesthese changes to the escape of carbonic acid in some cases; to achemical alteration, depending upon the absorption of oxygen, inothers; and again in others, especially where the expressed juicecoagulates on standing, to a loss of vitality, or disorganization ofthe molecules. To secure an eveness of tint on paper, the followingmanipulation is recommended:--The paper should be moistened on the backby sponging and blotting off. It should then be pinned on a board, themoist side downwards, so that two of its edges (suppose the right-handand lower ones) shall project a little beyond those of the board. Theboard then being inclined twenty or thirty degrees to the horizon, thealcoholic tincture (mixed with a very little water, if the petalsthemselves be not very juicy) is to be applied with a brush in strokesfrom left to right, taking care not to go over the edges which rest onthe board; but to pass clearly over those that project; and observingalso to carry the tint from below upwards by quick sweeping strokes, leaving no dry spaces between them, but keeping up a continuity of wetspaces. When all is wet, cross them by another set of strokes fromabove downwards, so managing the brush as to leave no floating liquidon the paper. It must then be dried as quickly as possible over astove, or in a warm current of air, avoiding, however, such heat as mayinjure the tint. 

In addition to the flowers already mentioned in my third chapter, thefollowing are among those experimented upon and found to give tolerablegood photographic sensitives. I can only enumerate them, referring thestudent, for any further information he may desire on the subject, toMr. Hunt's work; although what I have said above is sufficient for allpractical purposes; and any one, with the ambition, can readilyexperiment upon them, without further research, on any other flower hemay choose. 

Viola Odorata--or sweet sented violet, yields to alcohol a rich bluecolor, which it imparts in high perfection to paper

Senecio Splendens--or double purple groundsel, yields a beautiful colorto paper. 

The leaves of the laurel, common cabbage, and the grasses, are foundsufficiently sensitive. 

Common Merrigold yields an invaluable faecula, which appears identicalwith that produced by the Wall-flower, and Cochorus japonica mentionedbefore, and is very sensitive, but photographs procured upon it cannotbe preserved, the color is so fugitive. 

From an examination of the researches of Sir John Herschel on thecoloring matter of plants, it will be seen that the action of the sun'srays is to destroy the color, effecting a sort of chromatic analysis, in which two distinct elements of color are separated, by destroyingthe one and leaving the other outstanding. The action is confinedwithin the visible spectrum, and thus a broad distinction is exhibitedbetween the action of the sun's rays on vegetable juices and onargentine compounds, the latter being most sensibly affected by theinvisible rays beyond the violet. 

It may also be observed, that the rays effective in destroying a giventint, are in a great many cases, those whose union produces a colorcomplementary to the tint destroyed, or, at least, one belonging tothat class of colors to which such complementary tint may be preferred. For instance, yellows tending towards orange are destroyed with moreenergy by the blue rays; blues by the red, orange and yellow rays;purples and pinks by yellow and green rays. 

V. AMPHITYPE. 

This process is a discovery of Sir John Herschel and receives its namefrom the fact that both negative and positive photographs can beproduced by one process. The positive pictures obtained by it have aperfect resemblance to impressions of engravings with common printer'sink. The process, although not yet fully carried out, promises to beof vast utility. 

Paper proper for producing an amphitype picture may be prepared eitherwith the ferro-tartrate or the ferro-citrate of the protoxide, or theperoxide of mercury, or of the protoxide of lead, by using creams ofthese salts, or by successive applications of the nitrates of therespective oxides, singly or in mixture, to the paper, alternating withsolutions of the ammonia-tartrate or the ammonia-citrate of iron, thelatter solution being last applied, and in more or less excess. Ipurposely avoid stating proportions, as I have not yet been able to fixupon any which certainly succeed. Paper so prepared and dried takes anegative picture, in a time varying from half an hour to five or sixhours, according to the intensity of the light; and the impressionproduced varies in apparent force from a faint and hardly perceptiblepicture to one of the highest conceivable fulness and richness both oftint and detail, the color being in this case a superb velvety brown. This extreme richness of effect is not produced unless lead be present, either in the ingredients used, or in the paper itself. It is not, asI originally supposed, due to the presence of free tartaric acid. Thepictures in this state are not permanent. They fade in the dark, though with very different degrees of rapidity, some (especially iffree tartaric or citric acid be present) in a few days, while othersremain for weeks unimpaired, and require whole years for their totalobliteration. But though entirely faded out in appearance, the pictureis only rendered dormant, and may be restored, changing its characterfrom negative to positive, and its colors from brown to black, (in theshadows), by the following process:--A bath being prepared by pouring asmall quantity of solution of pernitrate of mercury into a largequantity of water, and letting the subnitrated precipitates subside, the picture may be immersed in it, (carefully and repeatedly clearingoff all air bubbles, ) and allowed to remain till the picture (if anywhere visible, ) is entirely destroyed; or if faded, till it is judgedsufficient from previous experience; a term which is often marked bythe appearance of a feeble positive picture, of a bright yellow hue, onthe pale yellow ground of the paper. A long time (several weeks) isoften required for this, but heat accelerates the action, and it isoften completed in a few hours. In this state the picture is to bevery thoroughly rinsed and soaked in pure warm water, and then dried. It is then to be well ironed with a smooth iron, heated so as barelynot to injure the paper, placing it, for greater security againstscorching, between clean smooth paper. If then the process have beensuccessful, a perfectly black positive picture is at once developed. At first it most commonly happens that the whole picture is sooty ordingy to such a degree that it is condemned as spoiled, but on keepingit between the leaves of a book, especially in a moist atmosphere, byextremely slow degrees this dinginess disappears, and the picturedisengages itself with continually increasing sharpness and clearness, and acquires the exact effect of a copper-plate engraving on a papermore or less tinted with a pale yellow. 

I ought to observe, that the best and most uniform specimens which Ihave procured have been on paper previously washed with certainpreparations of uric acid, which is a very remarkable and powerfulphotographic element. The intensity of the original negative pictureis no criterion of what may be expected in the positive. It is fromthe production by one and the same action of light, of either apositive or negative picture according to the subsequent manipulations, that I have designated the process, thus generally sketched out, by theterm Amphitype, --a name suggested by Mr. Talbot, to whom I communicatedthis singular result; and to this process or class of processes (whichI cannot doubt when pursued will lead to some very beautiful results, )I propose to restrict the name in question, though it applies even moreappropriately to the following exceedingly curious and remarkable one, in which silver is concerned:

At the last meeting I announced a mode of producing, by means of asolution of silver, in conjunction with ferro-tartaric acid, a dormantpicture brought into a forcible negative impression by the breath ormoist air. (See Cyanotype. ) The solution then described, and which hadat that time been prepared some weeks, I may here incidentally remark, has retained its limpidity and photogenic properties, quite unimpairedduring the whole year since elapsed, and is now as sensitive asever, --a property of no small value. Now, when a picture (for examplean impression from an engraving) is taken on paper washed with thissolution, it shows no sign of a picture on its back, whether that onits face is developed or not; but if, while the actinic influence isstill fresh upon the face, (i. E. , as soon as it is removed from thelight), the back be exposed for a very few seconds to the sunshine, andthen removed to a gloomy place, a positive picture, the exactcomplement of the negative one on the other side, though wanting ofcourse in sharpness if the paper be thick, slowly and gradually makesits appearance there, and in half an hour or an hour acquires aconsiderable intensity. I ought to mention that the "ferro-tartaricacid" in question is prepared by precipitating the ferro-tartrate ofammonia (ammonia-tartrate of iron) by acetate of lead, and decomposingthe precipitate by dilute sulphuric acid. When lead is used in thepreparation of Amphitype paper, the parts upon which the light hasacted are found to be in a very high degree rendered water proof. --SirJ. Herschel. 

This process is a new invention of our countryman, J. A. Whipple, Esq. , of Boston, and has been patented by M. A. Root, Esq. , of Philadelphia. It will be seen, however, from the previous pages of my work that Mr. Root is mistaken in regard to his being the first improvement patentedin this country, although it is unquestionably the first by anAmerican. Of this improvement Mr. Root says:

VI. "CRAYON DAGUERREOTYPE. "

"The improvement to which you refer is denominated "The CrayonDaguerreotype. " This invention made by Mr. J. A. Whipple, is the onlyimprovement in Daguerreotyping, I believe, for which Letters Patent forthe United States were ever issued. The pictures produced by thisprocess--which is of the simplest description imaginable--have theappearance and effect of very fine "Crayon Drawings, " from which theimprovement takes its name. Some of our most distinguished artistshave given it their unqualified admiration. Among them, our MezzotintoEngravers, especially John Sartain, Esq. , who, from his richembellishments to most of the leading Magazines and Annuals of thecountry, as well as from the celebrity of the superb Magazine whichbears his name, is so well known and so well qualified to judge of itsmerits. As an auxiliary to the artist, in furnishing heads to theMagazines, or other works, it is invaluable; the great object which itaccomplishes being to give a finer effect and more distinct expressionto all the features--the whole power of the instrument being directedto, and confined to the head. "

"The late hour at which this subject has been brought to our noticeprevents so full a description as we would otherwise have been glad tofurnish. The New England States have been disposed of; negotiationsfor any of the others can be made through M. A. Root, 140 Chestnutstreet, Philadelphia. "

"A series of beautiful portraits are about being prepared by the"Crayton Process" for the express purpose of being placed on theexhibition at the "Art Union, " when amateurs, artists, and the publicgenerally will have an opportunity of witnessing its effect. We areespecially gratified with this striking improvement, from theadvantages which it promises to the Daguerrean art. "

"It is admirably designed to excite a new interest on the subjectthrough the community, and in this way--and from its tendency to renderthe art more generally useful, and to elevate and distinguish it--tomake it to all a matter of more general importance. "

 "Yours respectfully, "M. A. ROOT. "

In our second edition, we hope--with Mr. Root's permission--to lay thewhole process before the public, although our artists must bear in mindthat Mr. Root's patent secures to him the exclusive right of itsapplication. 

CHAP. XI. 

ON THE PROBABILITY OF PRODUCING COLORED PICTURES BY THE SOLARRADIATIONS--PHOTOGRAPHIC DEVIATIONS--LUNAR PICTURES--DRUMMOND LIGHT. 

Having before noticed the fact that some advances had been made towardstaking Daguerreotypes in color, by means of solar rays, and expressedthe hope that the day was not far distant when this might beaccomplished, I here subjoin Mr. Hunt's remarks on this subject. 

Mr. Biot, in 1840, speaking of Mr. Fox Talbot's beautiful calotypepictures, considers as an illusion "the hope to reconcile, not only theintensity but the tints of the chemical impressions produced byradiations, with the colors of the object from which these radiationsemanated. " It is true that three years have passed away, and we havenot yet produced colored images; yet I am not inclined to consider thehope as entirely illusive. 

It must be remembered that the color of bodies depends entirely uponthe arrangement of their molecules. We have numerous very beautifulexperiments in proof of this. The bi-niodide of mercury is a finescarlet when precipitated. If this precipitate is heated betweenplates of glass, it is converted into crystals of a fine sulphuryellow, which remain of that color if undisturbed, but which becomesvery speedily scarlet if touched with any pointed instrument. Thisvery curious optical phenomena has been investigated by Mr. Talbot andby Mr. Warrington. Perfectly dry sulphate of copper is white; theslightest moisture turns it blue. Muriate of cobalt is of a pale pinkcolor; a very slight heat, by removing a little moisture, changes it toa green. These are a few instances selected from many which might begiven. 

If we receive a prismatic spectrum on some papers, we have evidencethat the molecular or chemical disturbance bears some relation to thecolor of each ray, or, in other words, that colored light so modifiesthe action of ENERGIA that the impression it makes is in proportion tothe color of the light it accompanies, and hence there results amolecular arrangement capable of reflecting colors differently. Someinstances have been given in which the rays impressed correspond withthe colors of the luminous rays in a very remarkable manner. * One ofthe most decided cases is that of the paper prepared with the fluorideof soda and nitrate of silver. Sir John Herschel was, however, thefirst to obtain any good specimens of photographically impressedprismatic colorations. 

* See Mr. Hunt's "Researches on Light. "

It was noticed by Daguerre that a red house gave a reddish image on hisiodized silver plate in the camera obscura; and Mr. Talbot observed, very early in his researches, that the red of a colored print wascopied of a red color, on paper spread with the chloride of silver. **

** In 1842, I had shown me a picture of a house in the Bowery, whichhad been repaired a few days previous, and in the wall a red brickleft. This brick was brought out on the Daguerreotype plate ofprecisely the same color as the brick itself. The same artist alsoexhibited to me, the full length portrait of a gentleman who were apair of pantaloons having a blue striped figure. This blue stripe wasfully brought out, of the same color, in the picture. --AMER. ED. 

"In 1840 I communicated to Sir John Herschel some very curious resultsobtained by the use of colored media, which he did me the honor ofpublishing in one of his memoirs on the subject from which I again copyit. "

"A paper prepared with muriate of barytes and nitrate of silver, allowed to darken whilst wet in the sunshine to a chocolate color, wasplaced under a frame containing a red, a yellow, a green, and a blueglass. After a week's exposure to diffused light, it became red underthe red glass, a dirty yellow under the yellow glass, a dark greenunder the green, and a light olive under the blue. 

"The above paper washed with a solution of salt of iodine, is verysensitive to light, and gives a beautiful picture. A picture thustaken was placed beneath the above glasses, and another beneath fourflat bottles containing colored fluids. In a few days, under the redglass and fluid, the picture became a dark blue, under the yellow alight blue, under the green it remained unchanged, whilst under theblue it became a rose red, which in about three weeks changed intogreen. Many other experiments of a similar nature have been triedsince that time with like results. 

"In the summer of 1843, when engaged in some experiments on papersprepared according to the principles of Mr. Talbot's calotype, I hadplaced in a camera obscura a paper prepared with the bromide of silverand gallic acid. The camera embraced a picture of a clear blue sky, stucco-fronted houses, and a green field. The paper was unavoidablyexposed for a longer period than was intended--about fifteenminutes, --a very beautiful picture was impressed, which, when heldbetween the eye and the light, exhibited a curious order of colors. The sky was of a crimson hue, the houses of a slaty blue, and the greenfields of a brick red tint. Surely these results appear to encouragethe hope, that we may eventually arrive at a process by which externalnature may be made to impress its images on prepared surfaces, in allthe beauty of their native coloration. "

PHOTOGRAPHIC DEVIATIONS. 

Before taking leave of the subject of photogenic drawing, I mustmention one or two facts, which may be of essential service tooperators. 

It has been observed by Daguerre, and others, in Europe, and probablyby some of our own artists, that the sun two hours after it has passedthe meridian, is much less effective in the photographic process, thanit is two hours previous to its having reached that point. This maydepend upon an absorptive power of the air, which may reasonably besupposed to be more charged with vapor two hours before noon. The fuseof the hygrometer may possibly establish the truth or falsity of thissupposition. The fact, however, of a better result being producedbefore noon being established, persons wishing their portraits taken, will see the advantage of obtaining an early sitting, if they wish goodpictures. On the other hand, if the supposition above mentioned provetrue, a too early sitting must be avoided. 

If we take a considerable thickness of a dense purple fluid, as, forinstance, a solution of the ammonia-sulphate of copper, we shall findthat the quantity of light is considerably diminished, at leastfour-fifths of the luminous rays being absorbed, while the chemicalrays permeate it with the greatest facility, and sensitive preparationsare affected by its influence, notwithstanding the deficiency of light, nearly as powerfully as if exposed to the undecomposed sunbeams. 

It was first imagined that under the brilliant sun and clear skies ofthe south, photographic pictures would be produced with much greaterquickness than they could be in the atmosphere of Paris. It is found, however, that a much longer time is required. Even in the clear andbeautiful light of the higher Alps, it has been proved that theproduction of the photographic picture requires many minutes more, evenwith the most sensitive preparations, than it does in London. It hasalso been found that under the brilliant light of Mexico, twentyminutes, and half an hour, are required to produce effects which inEngland would occupy but a minute; and travellers engaged in copyingthe antiquities of Yucatan have on several occasions abandoned the useof the photographic camera, and taken to their sketch books. Dr. Draper* has observed a similar difference between the chemical actionof light in New York and Virginia. This can be only explained by thesupposition that the intensity of the light and heat of these climesinterferes with the action of the ENERGIC rays on those sensitivepreparations which are employed. 

* I would here take occasion to remark that our country man, Dr. Draper, is very frequently quoted by Mr. Hunt in his "Researches. "

LUNAR PICTURES--DRUMMOND LIGHT. 

The Roman Astronomers state that they have procured Daguerreotypeimpressions of the Nebula of the sword of Orion. Signor Rondini has asecret method of receiving photographic images on lithographic stone;on such a prepared stone they have succeeded in impressing an image ofthe Nebula and its stars; "and from that stone they have been enabledto take impressions on paper, unlimited in number, of singular beauty, and of perfect precision. " Experiments have, however, proved that "noheating power exists in the moon's rays, and that lunar light will notact chemically upon the iduret of silver. "

It was at one time supposed that terrestrial or artificial lightpossessed no chemical rays, but this is incorrect--Mr. Brandediscovered that although the concentrated light of the moon, or thelight even of olefiant gas, however intense, had no effect on chlorideof silver, or on a mixture of chloride and hydrogen, yet the lightemitted by electerized charcoal blackens the salt. At the RoyalPolytechnic Institution pictures have been taken by means of sensitivepaper acted upon by the Drummond Light; but it must of course bedistinctly understood, that they are inferior to those taken by thelight of the sun, or diffused daylight. 

If our operators could manage to produce good pictures in this way theywould put money in their pockets, as many who cannot find time duringthe day would resort to their rooms at night. I throw out the hint inhopes some one will make the experiment. 

I have learned, since the above was written, that an operator in Bostonsucceeded a short time since in procuring very good pictures by the aidof the Drummond Light; but that the intensity of the light fallingdirectly upon the sitter's face caused great difficulty, and heabandoned it. This may, probably, be remedied by interposing a screenof very thin tissue paper tinged slightly of a bluish color. 

CHAP. XII. 

ON COLORING DAGUERREOTYPES. 

Nearly, if not quite all the various colors used in painting may bemade from the five primitive colors, black, white, blue, red andyellow, but for the Daguerrean artist it would be the best policy toobtain such as are required by their art already prepared. In amajority of cases, the following will be found sufficient, viz. 

 Carmine. Prussian Blue. White. Chrome Yellow, Gamboge, Yellow Ochre; or all three. * *Gamboge is best for drapery; Ochre for the face. Light Red. Indigo. Burnt Sienna. Bistre, or Burnt Umber. 

If, in coloring any part of a lady's or gentleman's apparel, it isfound necessary to produce other tints and shades, the followingcombinations may be used:

Orange--Mix yellow with red, making it darker or lighter by using moreor less red. 

Purple--This is made with Prussian blue, or indigo and red. Carmineand Prussian blue producing the richest color, which may be deepened inthe shadows by a slight addition of indigo or brown. 

Greens--Prussian blue and gamboge makes a very fine green, which may bevaried to suit the taste of the sitter or operator, by larger portionsof either, or by adding white, burnt sienna, indigo, and red, as thecase may require. These combinations, under different modifications, give almost endless varieties of green. 

Brown--May be made of different shades of umber, carmine and lamp-black. 

Neutral tint--Is composed of indigo and lamp-black. 

Crimson--Mix carmine and white, deepening the shaded parts of thepicture with additional carmine. 

Flesh Color--The best representative of flesh color is light red, brightened in the more glowing or warmer parts, with carmine, softenedoff in the lighter portions with white, and shaded with purple andburnt sienna. 

Lead Color--Mix indigo and white in proportions to suit. 

Scarlet--Carmine and light red. 

For Jewelry cups of gold and silver preparations accompany each box forDaguerreotypists, or may be procured separately. 

The method of laying colors on Daguerreotypes is one of considerabledifficulty, inasmuch as they are used in the form of perfectly dryimpalpable powder. The author of this little work is nowexperimenting, in order, if possible, to discover some more easy, artistic and unexceptionable method. If successful, the result will bepublished in a future edition. 

The rules we shall give for coloring Daguerreotypes depends, and arefounded, upon those observed in miniature painting, and are intendedmore as hints to Daguerrean artists, in hopes of leading them toattempt improvements, than as instructions wholly to be observed. 

The writer is confident that some compound or ingredient may yet bediscovered which, when mixed with the colors, will give a moredelicate, pleasing, and natural appearance to the picture than isderived from the present mode of laying them on, which in hisestimation is more like plastering than coloring. 

IN COLORING DAGUERREOTYPES, the principal shades of the head are to bemade with bistre, mixed with burnt sienna, touching some places with amixture of carmine and indigo. The flesh tints are produced by the useof light red, deepened towards the shaded parts with yellow ochre, blueand carmine mixed with indigo, while the warmer, or more highly coloredparts have a slight excess of carmine or lake. Color the shades aboutthe mouth and neck with yellow ochre, blue, and a very little carmine, heightening the color of the lips with carmine and light red, lettingthe light red predominate on the upper, and the carmine on the lowerlip; the shades in the corner of the mouth being touched slightly withburnt sienna, mixed with carmine. 

In coloring the eyes, the artist will of course be guided by nature, observing a very delicate touch in laying on the colors, so as topreserve as much transparency as possible. A slight touch ofblue--ultramarine would be best if it would adhere to the Daguerreotypeplate--in the whites of the eye near the iris, will produce a goodeffect. 

In coloring the heads of men it will be necessary to use the darkertints with more freedom, according to the complexion of the sitter. For women, the warmer tints should predominate, and in order to givethat transparency so universal with the softer sex--and which gives somuch loveliness and beauty to the face--a little white may bejudiciously intermingled with the red tints about the lighter portionsof the face. 

In taking a picture of a lady with light or auburn hair, by theDaguerrean process, much of the beauty of the face is destroyed, onaccount of the imperfect manner in which light conveys the image oflight objects to the spectrum of the camera. This may be obviated insome measure by proper coloring. To do this, touch the shaded partswith burnt sienna and bistre, filling up the lighter portions withyellow ochre, delicate touches of burnt sienna, and in those partswhich naturally have a bluish tint, add very delicate touches ofpurple--so delicate in fact as hardly to be perceived. The roots ofthe hair at the forehead should also be touched with blue, and theeyebrows near the temples made of a pinkish tint. 

The chin of a woman is nearly of the same color as the cheeks in themost glowing parts. In men it is stronger, and of a bluish tint, inorder to produce the effect given by the beard. 

In portraits of women--the middle tints on the side of the light, whichare perceived on the bosom and arms, are made of a slight mixture ofochre, blue and lake, (or carmine), to which add, on the shaded sides, ochre, bistre and purple, the latter in the darker parts. The tints ofthe hands should be the same as the other parts of the flesh, the endsof the fingers being a little pinkish and the nails of a violet hue. If any portion of the fleshy parts is shaded by portions of the dress, or by the position of the hand, this shade should be colored with umbermixed with purple. 

TO COLOR THE DRAPERY. --Violet Velvet--Use purple made of Prussian blueand carmine, touching up the shaded parts with indigo blue. 

Green Velvet--Mix Prussian blue and red-orpiment, shade with purple, and touch up the lights with a little white. 

Red Velvet--Mix a very little brown with carmine, shading with purple, marking the lights in the strongest parts with pure carmine, and touchthe most brilliant slightly with white. 

White Feathers--May be improved by delicately touching the shaded partswith a little blue mixed with white. White muslin, linen, lace, satin, silk, etc. , may also be colored in the same way, being careful not tolay the color on too heavily. 

FURS--Red Furs may be imitated by using light red and a littlemasticot, shaded with umber. Gray Furs--black and white mixed andshaded with bistre. Sable--white shaded lightly with yellow ochre. 

These few directions are quite sufficient for the art, and it is quiteunnecessary for me to pursue the subject further. I would, however, remark that the Daguerreotypists would find it greatly to theiradvantage to visit the studies of our best artists, our publicgalleries of paintings, and statuary, and wherever else they can obtaina sight of fine paintings, and study the various styles of coloring, attitudes, folds of drapery and other points of the art. In coloringDaguerreotypes, artists will find the magnifying glass of muchadvantage in detecting any imperfections in the plate or in the image, which may be remedied by the brush. In selecting brushes choose thosemost susceptible of a fine point, which may be ascertained by wettingthem between the lips, or in a glass of water. 

CHAP. XIII. 

THE PHOTOGRAPHOMETER. 

The last number (for March, 1849) of the London Art-Journal, gives thefollowing description of a recent improvement in PhotographicManipulation, and as I am desirous of furnishing everything new in theart, I stop the press to add it, entire, to my work. 

"Since the photographic power of the solar rays bears no directrelation to their luminous influence, it becomes a question ofconsiderable importance to those who practice the beautiful art ofphotography, to have the means of readily measuring the ever changingactivity of this force. Several plans more or less successful, havebeen devised by Sir John Herschel, Messrs. Jordan, Shaw and Hunt. Theinstrument, however, which is now brought forward by Mr. Claudet, whois well known as one of our most successful Daguerreotypists, appearsadmirably suited to all those purposes which the practical manrequires. The great difficulty which continually annoys thephotographic amateur and artist, is the determination of thesensibility of each tablet employed, relatively to the amount ofradiation, luminous and chemical, with which he is working. With thephotographometer of Mr. Claudet this is easily ascertained. Thefollowing woodcuts and concise description will sufficiently indicatethis useful and simple apparatus. 

[Illustration: Fig. 30 (hipho_30. Gif)]

"For an instrument of this kind it is important in the first place tohave a motion always uniform, without complicated or expensivemechanism. This is obtained by means founded upon the principle of thefall of bodies sliding down an inclined plane. The sensitive surfaceis exposed to the light by the rapid and uniform passage of a metalplate, A, B, (Fig. 31, ) having openings of different length, whichfollow a geometric progression. It is evident that the exposure tolight will be the same for each experiment, because the plate furnishedwith the proportional openings falls always with the same rapidity, theheight of the fall being constant, and the angle of the inclined planethe same. Each opening of this moveable plate allows the light to passduring the same space of time, and the effect upon the sensitivesurface indicates exactly the intensity of the chemical rays. Therapidity of the fall may be augmented or diminished by altering theinclination of the plane by means of a graduated arc, C, D, (Fig. 30, )furnished with a screw, E, by which it may be fixed at any angle. Thesame result may be obtained by modifying the height of the fall or theweight of the moveable plate. The photogenic surface, whether it bethe Daguerreotype plate, the Talbotype paper, or any other preparationsensitive to light, is placed near the bottom of the inclined plane, F. It is covered by a thin plate of metal, pierced with circular holes, which correspond to the openings of the moveable plate at the moment ofthe passage of the latter, during which the sensitive surface receivesthe light wherever the circular holes leave it exposed. 

[Illustration: Fig. 31 (hipho_31. Gif)]

"The part of the apparatus which contains the sensitive surface is anindependent frame, and it slides from a dark box into an opening on theside of the inclined plane. 

"A covering of black cloth impermeable to light is, attached to thesides of the moveable plate, enveloping the whole inclined plane, rolling freely over two rollers, R, R, placed the one at the upper andthe other at the lower part of the inclined plane. This cloth preventsthe light striking the sensitive surface before and after the passageof the moveable plate. 

"It will be seen that this apparatus enables the experimentalist toascertain with great precision the exact length of time which isrequired to produce a given amount of actinic change upon any sensitivephotographic surface, whether on metal or paper. Although at presentsome calculation is necessary to determine the difference between thetime which is necessary for exposure in direct radiation, and to theaction of the secondary radiations of the camera obscura; this is, however, a very simple matter, and it appears to us exceedingly easy toadapt an instrument of this description to the camera itself. 

"By this instrument Mr. Claudet has already determined many veryimportant points. Among others, he has proved that on the mostsensitive Daguerreotype plate an exposure of . 0001 part of a second issufficient to produce a decided effect. 

"Regarding photography as an auxiliary aid to the artist of no meanvalue, we are pleased to record a description of an instrument which, without being complicated, promises to be exceedingly useful. In thisopinion we are not singular; at a recent meeting of the PhotographicClub, to which this instrument was exhibited, it was with much realsatisfaction that we learned that several of our most eminent artistswere now eager and most successful students in Photography. Thebeautiful productions of the more prominent members of this clubexcited the admiration of all, particularly the copies of architecturalbeauties, and small bits of landscape, by Messrs. Cundell and Owen. Wethink that now the artist sees the advantage he may derive from the aidof science, that both will gain by the union. "

I hope the above description will induce our townsman, Mr. Roach, tosuccessfully produce an instrument that will meet the wants of ourartists in that part of the Daguerrean process referred to. 

FINIS. 

INDEX. 

 Accelerating Liquids. 65 Amphitype. 116 Anthotype. 113 Apparatus. Daguerreotype. 43 Calotype 97 Photogenic 87 Application of Photogenic Drawing. 95 Applying the Sensitive. 64

 Bringing out the Picture. 71 Bromine Box. 51 Chloride of 68 Roach's Tripple Compound of 67 water. 65 Bromide of Iodine. 67 of Lime. 68 Paper. 91 of silver. 35 Brushes. 88 Buff Sticks. 60

 Calotype process. 97 paper. Exposure in Camera of 100 Pictures. Bringing out ib. Fixing 101 Camera. Description of the 43 Stand. 49 Woodbridge's ib. Calotype. 50 Voigtlander 45 Chloride of Bromine. 68 of Gold. 36 to make a solution of 75 of Iodine. 66 of Silver. 31 Chromatype. 112 Chrysotype. 106 Cleaning and Polishing the plate. 61 Coating Boxes. 51 Color Boxes. 53 Colored Daguerreotypes on Copper. 77 Coloring the Picture. 76 Daguerreotypes. 129 Concave Mirrors. 19 Convex Mirrors 19 Corchorus Japonica. 37 Crayon Daguerreotypes. 120 Cyanotype 109

 Daguerreotype Apparatus. 43 Process. 61 Plates. 62 Daguerreotypes. Crayon 77 on paper 81 Dedication. Iii Definitions of terms used in optics, 15 Different methods of preparing photogenic paper. 89 Directions for use of Galvanic Battery. 58 Distilled water 88 Drummond light. 128 Dry Sensitive. 68 Drying apparatus. 72

 Effects of light on bodies 25 Energiatype 111 Etching Daguerreotypes. 83

 Fifth operation. Fixing the picture. 61 First operation. Cleaning the plate 61 Fluoric acid. 69 Fourth operation-Bringing out the picture. 71 Funnels. 53

 Galvanic Battery. 57 Solution for use of 58 Gilding stand. 53 the picture. 74 Gold. Chloride of 36 To make solution of 75 Hyposulphite; or Salt of 74 Preparation of. 36 Gurney's Sensitive. 67

 Head Rests. 57 Hints and Suggestions. 39 History of Photography. 3 Hungarian Liquid. 69 Hygrometers. 55 Hyposulphite of Gold. 74 of Soda. 28

 Instantaneous pictures by means of Galvanism. 77 Introduction. I Iodine, Dry 64 Chloride of 66 Bromide of 67 Box. 51 Iodide of silver. 32 Ioduret of silver. 33 Iodize the Plate. To 64 Iodized Paper for Calotypes. To prepare 98 To prepare for the Camera ib. 

 Lamps, Spirit 53 Light. Theory on 14 Motion of 16 Reflection of 17 Refraction of 20 on bodies. Effects of 25 Prismatic analysis of 22 Lime, Bromide of 68 Lunar Pictures. 127

 Mead's Accelerator. 68 Mercury Bath 50

 Nitrate of Silver. 89

 Oxide of Silver. 29 On coloring Daguerreotypes 129 On the probability of Producing colored Photographs. 123

 Paper. Blotting; or bibulous, 88 Daguerreotypes. 81 preparation of 89 suitable for Photographs. 87 Photogenic drawing on ib Photographic principle, the 22 Photographic process on paper. 92 drawing. Application of 95 To fix the 93 deviations. 126 Photographometer, The 135 Plate Support. 59 Blocks. 50 Vice. 51 Poppy, The Red 37 Porcelain dishes. 59 Positive Calotype 104 Preface. V Preparation of Iodized Paper. 98 of Gold. 36 Prismatic Spectrum. 22 Analysis of Light. Ib

 Reflection of Light. 17 Refraction of Light. 20 Roach's Tripple Compound of Bromine. 67

 Sand Clock. 70 Sealing paper. To make 77 Second operation. 94 Sensitive. Ib Silver. Bromide of 35 Chloride of 31 Iodide of 32 Ioduret of 33 Nitrate of 89 Oxide of 28 Solution of Chloride of 59 Sixth operation. 74 Soda Hyposulphite of 72 Solar and Stellar Light. 21 Still for purifying water, 54 Submitting the Plate to the action of Light 69 Synopsis of Mr. Hunt's Treatise on Light, 29

 Talbotype Camera. 50 Theory on Light. 14 Third operation. 69

 Wall Flower. 37