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.
Oxides
Substances combined with oxygen without being in a state of acid. The metallic oxides are the most important, and occur naturally as abundant and valuable ores. See METALS; ORES; REDUCTION OF ORES; OXYGEN. Oxidized Metal is silver or other metal subjected to a process of dipping into a boiling solution of hyposulphite of soda or ammonium sulphide, continuing the process until the required degree of discoloration has taken place. It may then be varnished with non-transparent varnish consisting of alcohol 18, red arsenic 3, castoroil 1. See DIPPING; LACQUERING; STAINING METALS.