Appleton's dictionary of machines, mechanics, engine-work, and engineering : illustrated with four thousand engravings on wood ; in two volumes (1873)
D. Appleton and Company · New York : D. Appleton and Co. · leaf 412
The copper obtained in the first smelting operation is impure, and classes not higher than a rii;h matter melted ore; its granules consist of copper, iron, sulphur, ic. This matt or coarse metal is oncemore calcined in the calcining-furnace, and then subjected to another smelting, by which…
Mechanical engineering · Mechanics · Engineering
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