The Spectrohelioscope

Abstract

IN the issue of NATURE for October 25, p. 628, is published an article by Prof. G. E. Hale on the spectrohelioscope. It may be of interest to readers of NATURE to know that, so early as 1912, I made experiments with such an instrument, using a rotating disc in which was cut a number of radial slits. Preliminary experiments were made and a rough model was constructed by the kind help and suggestions of Mr. F. Twyman, who also described the method to Prof. R. W. Wood. Unfortunately, owing to the pressure of more important work, these experiments were abandoned and the model dismantled, but not before certain conclusions were arrived at.