Molecular Physics: an Attempt at a Comprehensive Dynamical Treatment of Physical and Chemical Forces ¹

Abstract

II. §6. Double Refraction. A CCORDING to the theories both of Fresnel and of Neumann, double refraction is explained on the assumption that the elasticity of the ether in crystals which exhibit this phenomenon is different in different directions. The elasticity is proportional to the square of the velocity of propagation, and if a, b, c are the ratios of the elasticities, parallel to the principal axes of the crystal, of the ether within it to its density, the velocity in any direction α, β γ will be given by the equation.—