or OXIDE, in Chemistry, is the term used to denote a very numerous class of bodies formed by the union of certain bases with a smaller proportion of oxygen than what is necessary for their conversion into acids. The most remarkable of these bodies are what were formerly called metallic calces, and have for their base some metallic substance. It is in this state that metals are often contained in the ores, from which they are extracted, and converted into the metallic form, by the process called reduction. Metals are converted into oxides by combustion, and by solution in acids; and many of them assume this form from the action of the atmosphere alone, but more readily when this is assisted by moisture. See the history of the metals under Chemistry.

OXIDATION, or OXIDATION, is a term employed to express the process by which bodies are converted into oxides. See Metals under Chemistry.