Polarisation Experiment

Abstract

BY the following simple arrangement a single pile of glass plates may serve at once as polariser and analyser, and be used to study or to exhibit on a screen the interference colours with mica or crystal sections. It may not be new, but I have not seen it given anywhere. A beam of light is reflected down from a pile, polarised in the plane of reflection. Passing through a double-refracting crystal, it is resolved and then reflected by a common mirror under the crystal. On passing through the pile, which polarises by refraction in a plane at right angles to the plane of first polarisation, it shows the interference colours. Using sunlight and interposing a convex lens, we may by this simple means project the interference rings of crystal sections.