A Manual of Metallurgy

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VIII. SILVER. There is every evidence of the knowledge of silver from the very remotest ages. Thus, in the book of Job, it is said, Surely there is a vein for silver; and again, in the book of Genesis, we are told that Abraham bought the ground for his wife's burial-place, and, to pay for it,...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VIII. SILVER. There is every evidence of the knowledge of silver from the very remotest ages. Thus, in the book of Job, it is said, Surely there is a vein for silver; and again, in the book of Genesis, we are told that Abraham bought the ground for his wife's burial-place, and, to pay for it, weighed out four hundred shekels of silver, current with the merchants. And, somewhat later still, the Spanish peninsula was extremely productive of silver. In the middle ages, Austria was its chief source, in whose mines it was found as an associate metal with lead, and in the varying proportion of from 60 to 600 ounces to each ton of lead. It was also obtained plentifully in Saxony and the Hartz district. At the present day Mexico, Peru, and Chili, supply vast quantities of silver; in the former principally from the mining districts of Zacatecas and Guanaxuato. In Europe the Saxon mines yield much; and, lastly, our own island furnishes a very considerable quantity, all from lead-mines, much of which was formerly left in the lead; but, since the use of Mr. Pattinson's excellent process for its extraction, this silver has been profitably separated; so that, from this source, in one year alone, viz. 1852, the large amount of 800,000 ounces was obtained. Silver is found; ? First, as native silver, occurring in flat masses, at times arborescent, and often crystalline, thecube and octohedron being the prevailing forms, also the cubo-dodecahedron. Native silver is often associated in Mexico and Chili with iron in ferruginous rocks; whilst in America it occurs with native copper, large masses often being seen to consist of the two metals diffused, although distinct from each other. Also, as sulphide of silver, either alone, or mixed with certain other metals, viz. ir...