IV CONTENTS OF VOL. XX. SIXTH SERIES. 



Pago 



Intelligence and Miscellaneous Articles: — 



Reply to Mr. W. J. Harrison, by Dr. R. A. Houstoun . 247 

 On the Homogeneity of the y Kays of Kadi urn, by 

 Dr. K. D. Kleeman *. 248 



NUMBER CXVL— AUGUST. 



Mr. William Sutherland on Molecular and Electronic 

 Potential Energy 249 



Prof. A. P. Chattock on the Forces at the Surface of a 

 Needle-Point discharging in Air 266 



Prof. A. P. Chattock and Mr. A. M. Tyndall on the Ionizing 

 Processes at a Point discharging in Air. (Plate IA T .) .... 277 



Prof. Max Ma9on on the Flow of Energy in an Interference Field 290 



Dr. W. Miller on a Constant Pressure Gas Thermometer . . 296 



Messrs. Horace Lamb and Gilbert Cook : A Hydrodvnamical 

 Illustration of the Theory of the Transmission of Aerial 

 and Electrical Waves by a (J rating 303 



Dr. W. E. Sumpner and Mr. \Y. C. 8. Phillips on a Galvano- 

 meter for Alternate Current Circuits 309 



Mr. K. T. Beatty on the Production of Cathode Particles by 

 Homogeneous Rontgen Radiations, and their Absorption 

 by Hydrogen and Air. (Plate V.) 320 



Mr. Otto Stuhlmann on a Difference in the Photoelectric 

 Effect caused by Incident and Emergent Light 331 



Mr. Frederick Soddy on the Eolation between Uranium and 

 Radium. — V 340 



Mr. Frederick Soddy on the Kays and Product of Ura- 

 nium X.— II 342 



Mr. Frederick Soddy and Miss Kuth Pirret on the Ratio 

 between Uranium and Radium in Minerals 345 



Prof. Sir J. Larmor on the Statistical Theory of Kadiation . . 350 



Prof. J. Joly on the Amount of Thorium in Sedimentary 

 Rocks. — II. Arenaceous and Argillaceous Rocks 353 



M. C. Cheneveau on the Magnetic Balance of MM. P. Curie 

 and C. Cheneveau ; with an Appendix by A. C. Jolley. . . 357 



Prof. Charles G. Barkla on Typical Cases of Ionization by 

 X-Rays 370 



Prof. J. H. Jeans on the Motion of a Particle about a Doublet. 380 



Notices respecting New Books : — 



Bulletin of the Bureau of Standards, Vol. 6 382 



Intelligence and Miscellaneous Articles : — 



On the Homogeneity of the y Kays of Radium, by 



Mr. F. Soddy ..." ' 383 



On the Electrostatic Effect of a Changing Magnetic 



Field, by Prof. J. B. Whitehead _. 384 



On the Laws regarding the Direction of Thermo-electric 

 Currents enunciated by M. Thomas, by Dr. C. H. Lees. 384 



