CANDLE-POWER, the quality of brightness or intensity of a light. The international unit of intensity used in photometry (q.v.) is the international candle, which is one-tenth of the light given out by the Harcourt 10 candle-power pentane lamp, burn ing in an atmosphere containing o.8% parts by volume of water vapour and at normal pressure, and giving out ten times as much as the British standard candle (see CANDLE) of 1860.