﻿CONTENTS OF VOL. XXIII 



(SIXTH SERIES). 



NUMBER CXXXIIL— JANUARY 1912. 



Page 

 Prof. L. N. G. Eilon on the Investigation of Stresses in a 

 Rectangular Bar by means of Polarized Light. (Plates I. 

 & II.) 1 



Dr. Herbert Stansfield and Mr. H. P. "Walmsley on Changes 

 in Diffraction Spectra produced by Aberration and the 

 Aberration of an Echelon Grating. (PJates III. & IV.) . . 25 



Dr. J. R. Ashworth on the Magnetic Temperature Coefficients 

 of the Eerro-magnetic Elements in Corresponding States . 36 



Mr. Norman Campbell on Delta Rays 46 



Dr. W. E. G-. Swann : A Deduction of the Effects of Uniform 

 Translatory Motion, from the Electrical Theory of Matter, 

 without the Employment of a Transformation of the Elec- 

 tromagnetic Equations 64 



Dr. W. E. G. Swann on the EitzGerald Lorentz Contraction, 

 and an Examination of the Method of Determining the 

 Motions of Electrons, when considered simply as Singulari- 

 ties, moving so as to satisfy the Electromagnetic Scheme . 86 



Miss Ellen O'Connor on the Spectrum of the Magnesium 

 High-frequency Arc. (Plate V.) 94 



Mr. D. Tyrer on the Law of Molecular Attraction 101 



Mr. E. W. B. Gill on the Variation with Distance of the 

 Ionization produced by Rontgen Rays 114 



Mr. Clinton J. Davisson on the Positive Thermions from the 

 Salts of the Alkaline Earths 121 



Mr. Clinton J. Davisson on the Role Played by Gases in the 

 Emission of Positive Thermions from Salts 139 



Prof. E. F. Burton and Mr. W. B. Wiegand on the Effect of 

 Electricity on Streams of Water Drops. (Plate VI.) .... 148 



Prof. M. S. SmoluchowsM on Opalescence of Gases in the 

 Critical State 165 



Mr. J. C. Pomeroy on the Charges on Thermions produced 

 in Air and Hydrogen at Atmospheric Pressure 173 



Mr. Horace H. Poole on the Rate of Evolution of Heat by 

 Orano-ite 183 



Dr. J. N. Pring and Mr. A. Parker on the Ionization produced 

 by Carbon at High Temperatures 192 



