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.

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This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Excerpt from Comstock Mining and Miners To present these varied themes clearly and fairly in a well-joined narrative has been the aim of the writer. No assertion or statement of fact has been made without the citation of authorities. If, in any case, more positive evidence is desirable, its lack may fairly be attributed to the death of witnesses and the absence or destruction of trustworthy records. Cumulative evidence has only been cited when its support was clearly requisite, but all material obtained has been filed for reference among the manuscript records of the United States Geological Survey. No minute examination has been here essayed of subjects which have been elaborately treated in the complementary reports already published and now in press. For strictly technical discussions of the geology, chemistry, physics, and mechanics of the Lode, reference should be made to the standard treatises of Richthofen, King, Church, and Hague, and to the reports of Professor George F. Becker and W. R. Eckart, C. E., form ing the principal portion of the series of volumes treating of the Comstock Lode as the work was originally planned. It has been judged, however, that the investigation here attempted merits a place in the annals of mining in America, and is fittingly conducted under the direction of the United States Geological Survey. 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.