Excerpt from Rock Drills: Design, Construction, and Use In presenting this collection of essays on rock drills, I make claim to have treated the subjects exhaustively. Rock drills have formed the subject of numerous articles in the technical press. Various authors have dealt with the subject; but only incidentally and as a branch of other subjects. I kw of book that will, in the first place, give a description of the leading modem makes of English, Australian, and American drills of both piston and hammer types, or give such details of their actual use in metalliferous mines as would enable a vice to approach them with some previous kwledge; and, at the same time, assist the engineer and mine manager to choose machines most suited to his particular needs and to maintain and work them at their highest efficiency. This is my excuse for attempting such a task, while engaged in other mining work. I have t hesitated to reprint much of the writing of others, always, I hope, with due ackwledgment. Where the facts were stated concisely and clearly I saw object in transcribing. I had much help from H. P. Gillette's excellent book, C. LeNeve Foster's and other works on mining. I have borrowed largely from proceedings of scientific societies and from A. and Z. Daw's exhaustive work on Blasting Rock. Many thanks are due to manufacturers for much help. I have tried to write without bias in comparing the merits of various machines and devices, and the book is t an advertisement for any particular drill. I have t given much space to either rotary or gasoline drills as they scarcely come within the scope of the book. My apology to my critics, who will doubtless find many omissions in the book, is, that it is a collection of tes that the author himself would have been very pleased to have had in book form when recently selecting and working rock drills. My chief qualification for writing this book is, that I have had to earn my living by using many of the machines described, and more recently in superintending rock-drilling operations. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art techlogy to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.