PREFACE. IN preparing the present volume for publication, our object has rather been to make it a convenient book of reference than a popular description of Mining and Metallurgic operations. The Introductory Chapter is the result of a considerable amount of research, and presents in a tabular form a large collection of analyses of various ancient alloys. The subject of Mining Machinery has been treated of at some length, and simple rules are given for making the necessary calculations. A chapter on Superheated Steam has been introduced, which, from the novelty and importance of the facts adduced, may not, it is hoped, be found entirely without interest. The notice of recent improvements in Metallurgy includes some valuable additions to our knowledge of that art. We are indebted for the description of Sinding's method of treating copper ores to Mr. P. Worsley, who was for some time occupied in making experiments on the precipitation of copper by this means. We have also the pleasure of inserting a paper on the Joint Stock Act of 1856, by Mr. W. V. Venables, and another on Boring, by Mr. G. Darlington. The Assaying of all the more common varieties of ore is treated of in a concise and practical manner, and care has been taken only to introduce such methods as long experience has proved to be both simple and effective. Considerable misapprehension appears to prevail relative to Mining as a source of investment for capital. This subject will be found noticed at considerable length, and is illustrated by a series of Tables showing the commercial value of that class of industry. Mining Economics have received a due proportion of attention, and it is hoped that the various information arranged in a tabular form may be found to afford a convenient source of reference. The illustrations of this volume have been reduced from working drawings, and engraved on wood by Mr. F. De la Motte. LONDON, Sept., 1857. |