REFRACTION

n. Re-fra2k'sh'n. From refringere, to break up. Fr., refraction. Ger., Brechung, Refraktion. Deflection from a straight course; especially the change of direction of rays of light, heat, and sound in pa ing from one medium to another of different density, or through a medium the density of which is not uniform (cf. ANGLE of r. and Refractive INDEX), [a, 48.] Double r. Ger., Doppelbrechung. The breaking up of a ray of light into two rays, which proceed in different directions on emerging from the medium (such as Iceland spar) which produces this bifurcation. [a, 48.] R. equivalent. Ger., Refractions a qui val ent. A number expre ing the product of the specific refractive power of a substance by the molecular weight of the latter. This number, when calculated for the different members of an homologous series of organic chemical compounds, is found to vary according to more or le definite rules; and, its value being determined for the elementary bodies, its value for compounds can be deduced, at least in some instances. [Strecker (B).] [s. 387]