12260 A RUDIMENTARY TREATISE ON COAL AND COAL-MINING BY WARINGTON W. SMYTH, M.A., VICE-PRES. G. S.; PRES. R. G. S. OF CORNWALL; F.R.S. CHIEF INSPECTOR OF THE MINES OF THE CROWN AND OF THE DUCHY OF LOCKWOOD & CO., 7, STATIONERS' HALL COURT LUDGATE HILL 1873 PREFACE TO THE SECOND EDITION. As the present publishers of this work intend to issue a new edition of it as one of the "Rudimentary Treatises," for which series it was originally written, the author has gladly availed himself of the opportunity to correct some errors which had escaped notice in the former edition. He has also brought the statistics up to a recent date, and inserted notes bearing upon several. important topics. In the interval which has elapsed since the first publication of these pages, the most notable phase in coal-mining has been the attention bestowed by coalviewers and engineers on the farther application of machinery to three departments of their art; viz., the getting of the coal, the underground haulage, and the ventilation of the works. Many coal-cutters and several ingenious contrivances for wedging down the seam by hydraulic power have been patented, but neither of them has been as yet so commonly applied as to need full description in a work professing only an elementary and general character. The latter two subjects have |