﻿Vlll CONTENTS OF VOL. XXIII. SIXTH SERIES. 



Page 



Prof. C. Gr. Barkla and Mr. V. Collier on the Absorption of 



X-Rays and Fluorescent X-Ray Spectra 9S7 



Prof. H. L. Callendar on Anisotropic Expansion of a Drawn 



Tube of Vitreous Silica 998 



Notices respecting New Books : — 



Dr. G-. W. C. Kaye and Prof. T. H. Laby's Physical 

 and Chemical Constants and some Mathematical 

 Functions 1000 



Index , 1002 



P L A T E S. 



I. & II. Illustrative of Prof. L. N. G. Filon's Paper on the Investi- 

 gation of Stresses in a Rectangular Bar by means of 

 Polarized Light. 

 III. & IV. Illustrative of Dr. H. Stansfield and Mr. II. P. Walmsley's 

 Paper on Changes in Diffraction Spectra produced by 

 Aberration and the Aberration of an Echelon Grating. 

 V. Illustrative of Miss E. O'Connor's Paper on the Spectrum of 

 the Magnesium High-frequency Arc. 

 VI. Illustrative of Prof. E. F. Burton and Mr. W. B. Wiegand's 

 Paper on the Effect of Electricity on Streams of Water 

 Drops. 

 VII. Illustrative of Mr. L. V. King's Paper on Absorption 



Problems in Radioactivity. 

 VIII. Illustrative of Mr. Allan Ferguson's Paper on Photographic 

 Measurements of Pendent Drops. 

 IX. Illustrative of Mr. Karl T. Compton's Paper on the In- 

 fluence of the Contact Difference of Potential between 

 the Plates emitting and receiving Electrons liberated by 

 Ultra-violet Light on the Measurement of the Velocities 

 of these Electrons. 

 X. -XII. Illustrative of Prof. R. W. Wood's Paper on Selective 

 Reflexion, Scattering and Absorption by Resonating Gas 

 Molecules. 

 XIII.-XV. Illustrative of Prof. E. H. Barton and Mr. W. B. Kilby's 

 Paper on Simultaneous Vibration Curves for Strings and 

 Air of Violin. 

 XVI. Illustrative of Mr. A. I. Steven's Paper on the Composition 

 of Two Simple Harmonic Motions exhibitedrbv a Stretched 

 String 1 . 



