I. <i>The intensity of reflexion of X-rays by rock-salt</i>.—Part II

Abstract

Reflexion Formulce.1. | N a previous paper in the Philosophical Magazine t, Jl we described a series of measurements of the intensity of reflexion of X-rays by various planes of the rocksalt crystal structure.In analysing tile results obtained, ~ formula for the intensity of roflexion was assmned which is essentially the same as that obtained by Darwin :~ anti Compton §.Let the Intensity I0 of a beam of homogeneous X-rays, at a given point, be defined as the total amount of radiation falling on an area of one square centimetre at right-angles to the direction of the beam.If a crystal-element of volume dV, supposed to be so small that absorption of the rays by the crystal is inappreciable, be placed so that ig is bathed by the X-rays, and if it is turned with angular * Communicated by the Authors.