Excerpt from Tunneling by Machinery: Description of Perforators and Plans of Operations The length of the Mount Cenis drill is one hundred and six and one-third inches, its weight between six hundred and seven hundred pounds, too great to be handled except by machinery its length permits holes to be drilled only in directions nearly parallel. Its parts are numerous, its liability to derangement great. The cost of repairs so considerable that the expense of tunneling exceeds the cost by hand labor. A section of the Mount Cenis drill on a scale of one-eighth the full size is given in Plate 1, Fig. 1. 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 technology 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.