Download or read book The Heat of the Comstock Mines (Classic Reprint) written by John A. Church and published by . This book was released on 2015-08-04 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Heat of the Comstock Mines These high temperatures appear to be partly due to the usual sources of heat in mines, and partly to chemical action in the rock, for the average depth in which the heat rises one degree Fahrenheit from the surface downward varies with the ground. The copper-bearing lodes are therefore the hottest, and in Corn-wall heated ground is thought to be a good indication of copper, just as hot ground is looked upon in the Comstock mines as a favorable sign of ore. Temperature in the Comstock Mines. These readings were obtained by placing a thermometer in a drill-hole immediately after the hole was finished, and leaving it there for periods varying from ten minutes to half an hour. Very little or no difference was discovered between holes which were drilled wet or dry, or if wet, between holes which were naturally wet, and those which were made so artificially. No doubt there must be some difference due to these varying conditions, but they are so slight as to be completely masked by the steady flow of heat from the rock during the exposure of the thermometer. The holes in which the thermometers were placed were not sunk especially for this work of testing, but were the ordinary drill-holes made for the purpose of blasting the rock. They varied therefore from about ten inches to three feet in depth. No variations in the height of the thermometer were found to be caused by this difference of depth, and this also is quite reasonable. 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.