IN a recent communication, Hough and Goldsmith 1 have described a method of increasing the sharpness of interference fringes by high-contrast photography with controlled exposure. Although the ...

IN the course of some experiments on Poisson's ratio by Cornu's method 1, one of us (B. J. G.) used a photographic method of recording the observed fringes for sodium light. Ilford Thin Film Half Tone ...