Cuprous adj. (Chem.) Of, pertaining to, or derived from, copper; containing copper; said of those compounds of copper in which this element is present in its highest proportion.
... daylight, and the electric carbon light is more powerful even than sunlight. The photo-electric action of light belongs principally to the "chemically active" rays; this is shown by the fact that the production of electricity is extremely small behind a glass colored with cuprous oxide, and behind a film of a solution of quinine sulphate; while it is not appreciably diminished by a film of a solution of alum. The photo-electric excitability of fluor-spar crystals is increased by a moderate heat (80 ... — Scientific American Supplement, No. 288 - July 9, 1881 • Various
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