The Kerr Effect in Optically Active Liquids

Abstract

WHEN polarised light passes through an optically active liquid in an electrostatic or a magnetic field the phenomenon of double refraction observed with a non-active substance is complicated by the optical rotation, and the only method employed to study the birefringence has been to mix equal quantities of right- and left-handed samples of the compound to be investigated, so as to obtain a non-active liquid.. M. R. de Mallemann, in the Annales de Physique for July-August, making use of the Airy-Gouy principle that on the element of path dl the double refraction and the rotation act independently of one another, and that the resultant effect can be calculated by compounding the elementary vectors representing the two effects, derives formulae by means of which the true double refraction of the liquid can be derived from the observations. Measurements are described on pinene, turpentine, ethyl tartrate, carvone and camphor, in which Panthener's method of instantaneous charge was used, which, in spite of certain difficulties, gives fairly satisfactory results in all cases, and enables the birefringence of imperfect insulators to be determined. I