CONTENTS OF VOL. XLII. 



(SIXTH SERIES). 



NUMBER CCXLVIL— JULY 1921. 



Page 



Prof. W. L. Bragg, Mr. E. W. James, and Mr. C. H. Bosanquet 



on the Intensity of .Reflexion of X-Eays by Rock-Salt. ... 1 

 Prof. Barton and Miss Browning on Triple Pendulum's with 

 Mutual Interaction and the Analogous Electrical Cir- 

 cuits.— II. (Plate I.) 17 



Mr. L, C. Jackson on the Theory of the Oscillations in Three 



Coupled Electric Circuits . . . 35 



Prof. L. Vegard on Eecent Results of Northlight Investi- 

 gations and the Nature of the Cosmic Electric Eays. 



(Plate II.) 47 



Dr. W. E. Adeney and Mr. H. G. Becker on the Determi- 

 nation of the Eate of Solution of Atmospheric Nitrogen and 



Oxygen by Water 87 



Mr. E. A. Milne on Sound Waves in the Atmosphere 96 



Prof. K. Honda and Mr. Seibei Konno on the Determina- 

 tion of the Coefficient of Normal Viscosity of Metals. 



(Plates III.-VI.) . ". 115 



Mr. Edwin C. Kemble on the Probable Normal State of the 



Helium Atom 123 



Mr. W. Hughes on the Nature of Chemical Force and the 



Anomaly of Strong Electrolytes . , 134 



Mr. W. J. Walker on Fluid Discharges as affected by Ee- 



sistance to Plow 138 



Dr. E. W. Aston on the Mass Spectra of Chemical Elements. 



(Part 3.) (Plate VII.) 140 



Mr. J. A. Tom kins on the Direct Determination of the 



Powers of Lenses 144 



Prof. Harold Hilton on the Vibrations of a Crystalline Medium. 148 

 Prof. E. K. Eideal on the Critical Energy Increment and 



Trouton's Eule . '. 156 



Prof. A. Ogg on the Crystalline Structure of Antimony and 



Bismuth ; 163 



Prof. W. G. Duffield and Mr. T. H. Littlewood on the Cor- 

 rection of a Marine Barometer for Errors due to Swinging. 166 

 Mr. E. E. Eelf on the Sound emitted by Wires of Circular 



Section when exposed to an Air-Current 173 



Sir Oliver Lodge ou Light and Electrons 177 



Dr. H. Chatley on Latent Heat and Surface Energy — Cohesion. 183 

 Mr. Nikhilranjan Sen on a Type of Vibration of an Elastic 

 Spherical Shell 185 



