PREFACE. WHEN towards the close of the year 1895 the last copies of the fourth edition of my work on The Coal-fields of Great Britain were sold out, it became a question whether another edition should be issued but on conferring with my publisher on the subject it was considered undesirable to take this course, on the ground that the section of the public who take an interest in the matters discussed in that work had been sufficiently supplied. The demand for the book was certainly not exhausted but it was doubtful whether it would be sufficient to justify the I issue of a new edition. Had it been otherwise, I had intended to give greater prominence than had previously been done to the new coal-fields that have been discovered, and are being opened up, in our Colonial Empire and other parts of the world, and with this object in view I had been collecting the necessary information. Under these circumstances I have determined to revert to the purpose for which The Coal-fields of Great Britain was originally written as far back as I 860 namely, the investigation of the question regarding the coal-resources of the British Islands. At that time there was absolutely no reliable information on the subject and I have reason to believe that the estimates I was able to lay before the public, though necessarily imperfect, did something towards allaying an apprehension, then very generally entertained, that our coal-fields would not be able to endure for a long time, without exhaustion, the ever increasing drain to which they were being subjected. Some years later, in 1866, a Royal Commission, under the presidency of the Duke of Argyll, was appointed for the purpose, amongst other matters, of investigating the probable quantity of coal contained in the coal-fields of the United Kingdom, and to report on the quantity of such coal which may be reasonably expected to be available for use. The Commission, which was separated into five distinct committees, each having a distinct subject of investigation on which to report, issued their joint Report in 1871, containing an enormous mass of valuable matter supplied by experts, and others qualified to deal with the questions, besides the Commissioners themselves. As regards the main point of the remaining quantity of coal at that period available for future use, the results by the Commissioners somewhat largely exceeded those at which I had arrived by my own unaided labours but this is partly to be accounted for by the fact that the Commissioners included in their estimates seams below two feet in thickness which I had excluded, and which I still consider ought not to have been included in the estimates of resources of coal which might reasonably be expected to be available for use. The question of the duration of our coal-supplies has not, meanwhile, lost its interest or importance. The annual output of coal which, when the Commissioners first met together on their appointment, only amounted to about one hundred millions of tons, has now risen to nearly double that quantity, and by the end of the nineteenth century will, in all probability, reach that quantity. The progress of exhaustion is still proceeding, nor can we say that the annual quantity extracted has reached its highest limit. Coal is an exhaustible product of the crust of the globe, and the subterranean cellar when once exhausted cannot, like those of our houses, be replenished... --This text refers to an alternate Paperback edition.