(under subclass 43) Subject matter including a standard incandescent source of radiation together with structure to compare or facilitate the comparison of the unknown light radiation from a hot body or other emissive source with the visible radiation emitted from the incandescent standard.
(1) Note. Patents claiming electrical circuitry to cause current to flow through electric incandescent lamps which are light standards are placed here, whether the standard lamp is used for a temperature test or a light intensity test.
SEE OR SEARCH THIS CLASS, SUBCLASS:
218+, for photoelectric photometers.
230+, for visual photometers utilizing a light standard.
243.1+, for standards generally.
SEE OR SEARCH CLASS 313, Electric Lamp and Discharge Devices,
271, for support or spacing structure for incandescent filaments used for light emission, and subclass 315 for incandescent lamps.
