﻿T PI E 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OP SCIENCE. 



[SIXTH SERIES.] 



JANUAR Y 1912, 

 



I. The Investigation of Stresses in a Rectangular Bar hi/ 

 means of Polarized Light. By L. N. Gr. Filon, M.A., 

 B.Sc, F.R.S., Assistant Professor of Mathematics at 

 University College, London *. 



[Plates I. & II.] 



§ 1. Introduction. 



THE question of the distribution of stress across the 

 section of an elastic solid of rectangular shape has 

 recently been receiving some attention, both theoretically 

 and experimentally, chiefly in connexion with the problem of 

 stresses in dams f . The experiments to be described were 

 undertaken some years ago with a view to verifying the 

 results of de Saint- Venant relating to the parabolic distri- 

 bution of shear in a long bar of rectangular cross-section at a 

 distance from the points of loading. The method was further 

 applied to check certain theoretical results obtained by the 

 author % regarding the distribution of stress in such a bar 

 immediately below a concentrated load. 



The method used depends on the well-known property of 

 glass, that under mechanical stress it becomes doubly re- 

 fracting, and a plane wave of light traversing it is broken 



* Communicated by Prof. F. T. Trouton, F.R.S. 



f Pearson and Atcberley, Drapers Company Research Memoirs, 1900. 

 L. F. Richardson, " The Approximate Arithmetical Solution by Finite 

 Differences of Physical Problems/' Phil. Trans. A. vol. ccx. pp. 307-358. 

 E. N. da C. Andrade, R. S. Proc, A. vol.lxxxv. pp. 448-401. 



t L. N. G. Filon, Phil. Trans. A. yol, cci. pp. 03-155. 



Phil. Mag. S. 6. Vol. 23. No. 133. Jan. 1912. B 



