CONTENTS OF VOL. XXIV. SIXTH SERIES. V 



Page 

 Mr. V. E. Pound on the Secondary Bays excited by the a Bays 



of Polonium.— II . . . 401 



Mr. H. Davies on some Applications of the Law of the Becti- 



linear Diameter = 415 



Dr. A. M. Tyndall on the Spread of the Discharge from an 



Electrified" Point 424 



Dr. A. S. Eve : A Comparison of the Ionization within closed 



vessels due to Bontgen and Gamma Eays . 432 



Prof. A. Anderson and Mr. T< Keane on the Theory and 

 Measurement of Eesidual Charges ............ ........ 437 



Dr. W. E. G-. Swann on the Motion of the Needle of a 



Quadrant Electrometer 445 



Prof. A. L. Clark : Density of Liquids and Eefractive Index of 



Liquids in Contact 451 



Notices respecting New Books: — 



Dr. Duncan M. T; Sommerville's Bibliography of Non- 

 Euclidean Geometry, including the Theory of Parallels, 

 the Eoundations of Geometry, and Space of n Dimen- 

 sions 452 



NUMBEE CXLIL— OCTOBEB. 

 Prof. E. Eutherford on the Origin of /3 and y Eays from 



Eadioactive Substances ............. -. ; , . . 453 



Prof. II. A. Bumstead and Mr. A. G. McGougan on the 



Emission of Electrons by Metals under the Influence of 



Alpha Eays 462 



Dr. J. E. Mills on the Law of Molecular Attraction 483 



Prof. D. N. Mallik: Theorv of Electric Discharge in a 



De La Rive's Tube ..../. . . 500 



Prof. E. P. Adams and Mr. C. Vf. Heaps on Changes in the 



Dielectric Constant produced by Strain 507 



Mr. C. Y. Eaman on the Maintenance of Eorced Oscillations 



of a New Type. (Plates X.-XII.) 513 



Prof. J. C. McLennan on the Eelative Intensities of the 



Earth's Penetrating Eadiation on Land and Sea 520 



Dr. Norman Campbell : Further Experiments on Delta Eays. 527 

 Mr. E. E. Smith on Bridge Methods for Besistance Measure- 

 ments of High Precision in Platinum Thermometry 541 



Prof. O. W. Eichardson on the Theory of Photoelectric Action. 570 

 Prof. O. W. Eichardson and Mr. Karl T. Compton on the 



Photoelectric Effect. (Plate XIII.) 575 



Mr. J. Chadwick : The y E.ays excited by the j3 Eays of 



Eadium .......;..., 594 



Mr. George E. Becker : The Gudermannian Complement and 



Imaginary Geometry 600 



Miss P. M. Borthwick on Potential Measurements in the 



Neighbourhood of the Electrodes in Point-plane Discharge. 608 



