Excerpt from Catalogue of the Mechanical Engineering Collection in the Science Division of the Victoria and Albert Museum, South Kensington, Vol. 2: With Descriptive and Historical Notes When a reference is made in the text, it is to the serial numbers at the beginning of each entry. When an object is illustrated the reference is given immediately after the entry. The numbers on the right hand lower corner are those under which the objects are registered in the Museum, and the dates given are generally those when the objects were first received. Mining Appliances. Deep Boring. - It is usual, before commencing more extended operations, to ascertain by borings of small diameter, the nature of the strata to be traversed, and the depth and extent of mineral deposits when reached. Two methods are used: - rotation and percussion. In the first method, in soft ground, shell or screw augers, rotated by hand or by power according to the depth, can be used. The connections to the tool, as the depth increases, are made by adding rods with screwed joints (see No. 1,001). The auger when full, must be drawn up, necessitating unscrewing and screwing up again the line of rods. This loss of time may be avoided by forcing down a current of water to carry up the fragments. Sometimes the lining tube is provided with a steel cutting edge and itself rotated. 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.