CONTENTS Of VOL. 



(SIXTH ffl&IES)r y 



£ 





NUMBER XCVII.— JAml^BY 1909. ' 



Page 

 Mr. S. H. Burbury on the Law of Probability for a System 



of Correlated Variables 1 



Prof. E. Taylor Jones : Electrical Oscillations in Coupled 



Circuits. (Plate I.) 28 



Mr. G. F. C. Searle on the Impulsive Motion of an Electrified 



Sphere 43 



Dr. C. V. Burton on a Modified Theory of Gravitation .... 71 



Mr. F. L. Hitchcock on the Double Nature of Nabla 113 



Mr. V. E. Pound on the Absorption of the Different Types 

 of Beta Rays, together with a Study of the Secondary 



Rays excited by them. (Plate II.) 126 



Dr. R. A. Houstoun on the Damping of Long Waves in a 



Rectangular Trough 154 



Mr. A. Stephenson on the Frequency Ranges of Non-gene- 

 rating Force exerting Cumulative Influence 164 



Mr. W. Makower on the Number and the Absorption by 



Matter of the /3 Particles emitted by Radium 171 



Mr. N. Campbell on the Absorption of /3 Rays by Liquids . . 180 

 Prof. W. B. Morton on the Amount of "Water in a Cloud 



formed by Expansion of Moist Air 190 



Mr. A. E. Dunstan on the Coefficient of Viscous Traction of 



Lead and Tin Alloys 192 



Mr. T. Royds on the Grating Spectrum of Radium Emanation. 202 

 Mr. C. V. Raman : The Experimental Study of Huygens's 



Secondary Waves. (Plate III.) 204 



Mr. W. Wilson on the Effect of Pressure on the Natural 

 Ionization in a Closed Vessel, and on the Ionization pro- 

 duced by the y Rays 216 



Notices respecting New Books : — 



Bulletin of the Bureau of Standards 226 



Proceedings of the Geological Society : — 



Mr. Cowper Reed and Prof. S. H. Reynolds on the 

 Fossiliferous Rocks of the Southern Half of the Tort- 

 worth Inlier 226 



Mr. H. J. LI. Beadnell on the Relations of the Nubian 



Sandstone and the Crystalline Rocks of Egypt .... 227 

 Dr. A. R. Dwerryhouse on some Intrusive Rocks in the 

 Neighbourhood of Eskdale (Cumberland) 228 



