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 358
ex steel button. The iron ring, which may be roughly made, is used so long as it is not burned, andoften serves for twenty and more successive cupels and smeltings. Each refining, or assay, requires inall cases a fresh cupel. The moistening of the ashes for making the cupel is a delicate operation,… … * Overruanr/s Metallurgy. 356 CUPEL.
Mechanical engineering · Mechanics · Engineering
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