| 释义 |
actinometer|ˌæktɪˈnɒmɪtə(r)|
[f. actino- + µέτρον measure.]
1. An instrument for measuring the intensity of the sun's heating rays; first invented by Sir John Herschel, and described in Edinb. Journal of Science for 1825.
1833Sir J. Herschel Brit. Assoc. Report 379 The actinometer is an instrument..for measuring at any instant the direct heating power of the solar rays. 1879Photogr. in Cassell's Techn. Educ. III. 326 The consequent progress of the printing may be most accurately determined by means of the actinometer. 1880Radcliffe in Contemp. Rev. Feb. 210 In interplanetary space, if the experiments with the actinometer are to be trusted, the temperature is not less than 256° Fahrenheit below the freezing point of fresh water.
2. Photogr. (See quots.)
1866J. W. Swan in Brit. Jrnl. Photogr. 16 Mar. 125/2, I name the instrument the ‘photographic Actinometer’, because it is exclusively designed for regulating the exposure in photographic printing. 1926Tansley & Chipp Aims & Methods in Study of Vegetation 93 The ordinary photographic ‘actinometer’ or ‘exposure meter’ is a very useful instrument for roughly measuring the relative light intensities of different habitats. 1958M. L. Hall et al. Newnes Compl. Amat. Photogr. vii. 94 Actinometers. Used for many years, but now obsolete, these measured the light intensity falling on the subject by the time taken by a printing-out paper to darken to match a standard tint. |