CONTENTS OF VOL. XXX. SIXTH SERIES. V 



Page 



.Dr. L. Silberstein ou Mutual Electromagnetic Mass 370 



Prof. E. P. Harrison and Mr. Sujit K. Chakravarti on the 

 Temperature Coefficient of Young's Modulus for Electrically 



Heated Iron Wire 373 



Prof. Prank Horton on the Zeleny Electroscope 381 



Prof. "W. M. Thornton on the Total Radiation from a Gaseous 



Explosion 383 



Prof. Yf. G. DurHeld: A Comparison of the Arc and Spark 

 Spectra of Nickel produced under Pressure ; with a Note 

 upon the Influence of Temperature and Density Gradients 



upon the Displacements of Spectrum Lines 385 



Dr. N. Bohr on the Quantum Theory of Radiation and the 



Structure of the Atom 391 



Prof. J. C. McLennan and Mr. C. L. Treleaven on Residual 



Ionization in Gases 415 



Prof. J. 0. McLennan and Mr. H. G. Murray on the Residual 



Ionization in Air enclosed in a vessel of Ice. (Plate V.). . 428 

 Mr. G. H. Livens on the Electron Theory of the Optical 



Properties of Metals.— II 434 



Notices respecting New Books : — 



Calculus Made Easy 445 



Proceedings of the Geological Society : — 



Prof. T. McKennv Hughes on the Gravels of East Anglia 445 

 Messrs. E. M. Anderson and E. G. Radley on the Pitch- 



stoiH'S of Mull and their Genesis 447 



Mr. II. S. Shelton on the Radioactive Methods of Deter- 

 mining Geological Time 448 



NUMBER CLXXVIIL— OCTOBER. 



Mr. C. F. Meyer and Prof. R. W. Wood : A Further Study 



of the Eluorescence produced by Ultra-Schumann Rays. 

 (Plate VI.) 449 



Mr. E. Talbot Paris on the Polarization of Light scattered by 

 Spherical Metal Particles of Dimensions comparable with 

 the Wave-length 450 



Prof. J. C. McLennan and Mr. Evan Edwards on the Ultra- 

 violet Spectrum of Elementary Silicon 482 



Prof. J. C. McLennan and Mr. I). A. Keys on the Mobilities 

 of Ions in Air at High Pressures 484 



Prof. J. C. McLennan and Mr. C. G. Pound on the Delta 

 Radiation emitted by Zinc when bombarded by Alpha Ravs. 

 (Plate VII.) 491 



Mr. W. B. Haines on Ionic Mobilities in Hydrogen and 

 Nitrogen 503 



