CONTENTS OF VOL. XXII. SIXTH SERIES. V 



Page 

 NUM13EE CXXIX.— SEPTEMBER. 



Prof. J. Joly on the Age of the Earth. (Plate III.) 3">7 



Lord Rayleigh : Problems in the Conduction of Heat ...... 38 L 



Prof. C. G. Barkla on the Spectra of the Fluorescent Rontgen 



.Radiations - 396 



Mr. E. W. B. Gill on the Intensity of the Ultra- Violet Light 



emitted by an Electrical Discharge at Low Pressures .... 412 

 Mr. G-. N. Antonoff on the Disintegration Products of 



Uranium 419 



Mr. A. Norman Shaw on Increased Accuracy in the Use of 



Bifilar Suspensions 433 



Dr. C. A. Sadler on the Transformation of the Energy of 

 Homogeneous Rontgen Radiation into Energy of Corpus- 

 cular Radiation - 447 



Dr. R. C. Tolman : Non-Newtonian Mechanics. — The Direc- 

 tion of Force and Acceleration 458 



Notices respecting New Books : — 



Prof. J. A. Fleming's Principles of Electric Wave 



Telegraphy and Telephony 403 



Proceedings of the Geological Society : — 



Mr. II. H. Thomas on the Skomer Volcanic Series .... 465 

 Mr. R. H. Rastall on the Geology of the Districts of 



AVorcester, Robertson, and Ashton (Cape Colony) . . 466 

 Mr. A. AVade on the Eastern Desert of Egypt, with 

 Considerations bearing upon the Origin of the British 



Trias 467 



Mr. A. Wade on the Llandovery and Associated Rocks 

 of North-Eastern Montgomeryshire -167 



NUMBER CXXX.— OCTOBER. 



Prof. R. W. AVood on the Resonance Spectra of Iodine 

 Vapour and their Destruction bv Gases of the Helium 

 Group. (Plates IV. & V.) 4C9 



Mr. J. Prescott on the Rigidity of the Earth 481 



Dr. J. H. Vincent : Electrical Experiments with Mercury 

 contained in Tubes. (Plates VI. & VII.) 506 



Prof. Augustus Trowbridge and Mr. Irving B. Crandall on 

 Groove-Form and Energy Distribution of Diffraction 

 Gratings. (Plates VIIT.-XI.) 534 



Dr. J. Franck and Dr. ~\V. Westphal on the Question of 

 Valency in Gaseous Ionization 547 



Dr. A. S. Eve on the Number of Tons produced by the Beta 

 Rays and by the Gamma Rays from Radium C 551 



Dr. Gwilym Owen on the Production of Nuclei in Air by 

 Intense Cooling 563 



Dr. R. D. Kleeman on Molecular Attraction and the Pro- 

 perties of Liquids 566 



