The Progress of America From the Discovery by Columbus to the Year 1846 (Volume 1, pt. 1) - Softcover
Inhaltsangabe
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1847. Excerpt: ... with hewn stone of the hardest quality. Transversely through an upright post which turns upon its axis in the centre of the plan, passes a shaft of wood, at each end of which are attached by cords one or two grinding-stones with smooth flat surfaces, which are dragged (by mules fastened to the extremities of the shaft) slowly around upon the bottom of the cistern, into which the ore is thrown after being pounded into small pieces. It is here ground, with the addition of water, into an impalpable mortar, by the constant friction of the dragging stones against the sides and bottom of the cistern. A suitable quantity of quicksilver is perfectly mixed with the mortar; to which, are added some muriates, sulphates, and other chemical substances, to facilitate the amalgamation. The compound is then piled up in small heaps, and not disturbed again until this process is supposed to be complete, when it is transferred to the washing-machine. Those I have observed are very simple, consisting of a kind of stone tub, into which a stream of water is made to flow constantly, so as to carry off all the lighter matter, which is kept stirred up by an upright studded with pegs, that revolves in the centre, while the amalgamated metals sink to the bottom. Most of the quicksilver is then pressed out, and the silver submitted to a burning process, by which the remaining portion of mercury is expelled. "The Bilver which is taken from the furnace generally contains an intermixture of gold, averaging from ten to thirty per cent; but what is extracted by amalgamation is mostly separated in the washing. While in a liquid state, the gold, from its greater specific gravity, mostly settles to the bottom; yet it usually retains a considerable alloy of silver. The compound is distinguis...
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Reseña del editor
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1847. Excerpt: ... with hewn stone of the hardest quality. Transversely through an upright post which turns upon its axis in the centre of the plan, passes a shaft of wood, at each end of which are attached by cords one or two grinding-stones with smooth flat surfaces, which are dragged (by mules fastened to the extremities of the shaft) slowly around upon the bottom of the cistern, into which the ore is thrown after being pounded into small pieces. It is here ground, with the addition of water, into an impalpable mortar, by the constant friction of the dragging stones against the sides and bottom of the cistern. A suitable quantity of quicksilver is perfectly mixed with the mortar; to which, are added some muriates, sulphates, and other chemical substances, to facilitate the amalgamation. The compound is then piled up in small heaps, and not disturbed again until this process is supposed to be complete, when it is transferred to the washing-machine. Those I have observed are very simple, consisting of a kind of stone tub, into which a stream of water is made to flow constantly, so as to carry off all the lighter matter, which is kept stirred up by an upright studded with pegs, that revolves in the centre, while the amalgamated metals sink to the bottom. Most of the quicksilver is then pressed out, and the silver submitted to a burning process, by which the remaining portion of mercury is expelled. "The Bilver which is taken from the furnace generally contains an intermixture of gold, averaging from ten to thirty per cent; but what is extracted by amalgamation is mostly separated in the washing. While in a liquid state, the gold, from its greater specific gravity, mostly settles to the bottom; yet it usually retains a considerable alloy of silver. The compound is distinguis...
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