Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
White Tombac
When copper is combined with arsenic, by melting them together in a close crucible, and covering the surface with common salt, to prevent oxidation, a white brittle alloy is formed. 3444. Speculum Metal for Telescopes. Melt 7 pounds of copper, and when fused add 3 pounds zinc and 4 pounds tin.
These metals will combine to form a beautiful alloy of great lustre, and of a light yellow color, fitted to be made into specula for telescopes. Mr. Mudge used only copper and grain tin, in the proportion of 2 pounds of the former to 14 ounces of the latter.
It is said to answer well for chill moulding, that is, for pouring in metal moulds, by which method it is rendered very homogeneous. changed by the addition of a small proportion The crystalline nature of the zinc is entirely of copper, iron, &c. The alloy is hard, closegrained, and resembles steel. Moreover, it is easier to file than either zinc or copper. The use: following table presents the proportions in Zinc. 1001 110 Copper. Cast Iron.
Lead. 90 8 91 8 92 7 0 97 21 0 97 3 0 0