spectrum

(spek’trum). pl. spectra [L. “ image "’]. A variously colored band into which light is decomposed in pa ing through a prism or grating of gla . absorption s., one afforded by light which has pa ed through various gaseous media, each yas absorbing those rays of which its own spectrum is composed. chemic s., that part of the spectrum which includes the ultra-violet or actinic rays. chromatic s., that part of the spectrum which includes the visible rays. con- The tinuous s., one in which Fraunhofer’s lines are not developed. diffraction-s., a spectrum formed by the pa age of light through a diffraction grating. fortification s. See tichopsia. gaseous 8., one which is afforded by an incandescent gas. ocular s. Same as after-image. prismatic s., one obtained by refraction through aprism. solar s., that which is afforded by sunlight. thermal s, that part of the spectrum which contains the ultra-red or heat rays. toxin s., a diagram in the form of a spectrum employed by Ehrlich to show the neutralizing power of antitoxin.