| radiometer | 1. A forestaff. 2. <physics> An instrument designed for measuring the mechanical effect of radiant energy. It consists of a number of light discs, blackened on one side, placed at the ends of extended arms, supported on an a pivot in an exhausted glass vessel. When exposed to rays of light or heat, the arms rotate. Origin: L. Radius radius: cf. F. Radiometre. Source: Websters Dictionary (01 Mar 1998) |
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| photographic | Of or pertaining to photography; obtained by photography; used ib photography; as a photographic picture; a photographic camera. Photograph"ically, Photographic printing, the process of obtaining pictures, as on chemically prepared paper, from photographic negatives, by exposure to light. Origin: Cf. F. Photographique. Source: Websters Dictionary (01 Mar 1998) |