CONTENTS OF VOL. XXXI. 



(SIXTH SERIES). 



NUMBER CLXXXL— JANUARY 1916. 



Pag« 



Sir George Greenhill : Skating on Thin Ice . . . 1 



Mr. James Kam : A Criticism on van der Waals' Equation 



and some new Equations derived therefrom 22 



Dr. Allan Ferguson on the Variation of Surface-Tension with 



Temperature 37 



Messrs. C. V. Raman and S, Appaswamaiyar on Discontinuous 



"Wave-Motion, (Plate I.) 47 



Prof. J. A. Pollock on the Relation between the Thermal 

 Conductivity and the Viscosity of Gases with reference to 



Molecular Complexity 52 



Mr. E. J. Evans : Some Observations on the Absorption 



Spectra of the Vapours of Inorganic Salts. (Plate II.) . . 55 

 Mr. W. Morris Jones on the most Effective Primary Capacity 



for Tesla Coils , 62 



Prof. L J. Sch watt : Methods for the Summation of certain 



Types of Series . , . » 75 



Dr. L. Vegard on the Structure of Silver Crystals 83 



Notices respecting New Books : — 



Prof. J. Pierpont's Functions of a Complex Variable . . 88 

 Intelligence and Miscellaneous Articles : — 



On the Structure of the Spinal Group of Crystals, bv 

 Prof. W. HL Bragg ........ 88 



NUMBER CLXXXIL— FEBRUARY. 



Lord Rayleigh on the Propagation of Sound in narrow Tubes 

 of variable section 89 



Prof. J. A. Pollock on the Wave-length of the Electrical 

 Vibration associated with a thin Straight terminated Con- 

 ductor 96 



