[f. Gr. βολή beam of light + μέτρον measure.] An electrical instrument of great sensitiveness for measuring radiant heat. Hence Bolometric a.
1882. Nature, XXV. 14/2. An instrument … capable of indicating a change of temperature as minute as 1-100,000th of a single Centigrade degree…. The instrument is termed by its discoverer, Prof. S. P. Langley, the bolometer, or actinic balance.
1882. Athenæum 2 Sept., 310/1. His ‘bolometer,’ or radiation measurer—an instrument some twenty times more sensitive than the thermopile.
1881. C. A. Young, Sun, 306. Shown by the bolometric measures described above.
