﻿CONTENTS OF VOL. XLIV.— SIXTH SERIES. VII 



NUMBER CCLXIV,— DECEMBER. 



Page 



Mr. 1!. Hargreaves on Atomic Systems based on Free Electrons, 

 positive and negative, and their Stability 1065 



Prof. R. AY. Wood on Selective Reflexion of X. 2536 by Mercury 

 Vapour 1105 



Prof. R. W. Wood on Polarized Resonance Radiation of Mercury 

 Vapour. (Plate IX.) . ._ _ 1107 



Mr. S. J. Barnett on Electric Fields due to the Motion of Constant 

 Electromagnetic Systems 1112 



Prof. Megh Nad Saba on the Temperature Ionization of Elements 

 of the Higher Groups in the Periodic Classification 1128 



Prof. F. Uorton and Dr. A. C. Davies on the Ionization of Ab- 

 normal Helium Atoms by Low-Voltage Electronic Bombardment. 1140 



Prof. J. S. Townsend on the Ionizing Potential of Positive Ions . . 1147 



Dr. G. Breit on the Propagation of a Fan-shaped Group of Waves 

 in a Dispersing Medium 1149 



Prof. E. Keighlley Rideal on the Flow of Liquids under Capillary 

 Pressure '.1152 



Prof. S. Russ and Mr. L. H. Clark on a Balance Method of mea- 

 suring X-Rays 1 1 59 



Mr. J. W. T. Walsh on the Measurement of Light 1165 



Notices respecting New Books : — 



The Cambridge Colloquium, 1916 : Part 1 1169 



Mr. J. Edwards's A Treatise on the Integral Calculus : Vol. II. 1169 



Index 1170 



