CONTENTS OF VOL, XXIV. 



(SIXTH SERIES). A* 



\ 



■-=_ u % 



NUMBER CXXXIX.— JULY 1912. <v 



Dr. James G. Gray on the Magnetic Properties df^a Graded 

 Series of Nickel-Manganese Alloys. (Plate I.) .X..... 1 



Dr. E. N. da C. Andrade : Some Experiments on the Elec- 

 trical Behaviour of Metallic Vapours in Eiames 15 



Dr. C. D. Cooksey on the Asymmetry in the Distribution of 

 Secondary Cathode Rays produced by X-Bays ; and its 

 Dependence on the Penetrating Power of the Excitiug 

 Rays 37 



Mr. Horace H. Poole on the Thermal Conductivity of some 

 Rocks at High Temperatures 45 



Mr. P. W. Bridgman on Breaking Tests under Hydrostatic 

 Pressure and Conditions of Rupture. (Plate II.) 63 



Dr. W. F. G. Swann on the Earth's Magnetic "Field 8l> 



Dr. K.. D. Kleeman on the Kinetic Properties of a Molecule 

 in a Substance 101 



Prof. H. A. Wilson on the Diffusion of Alkali Salt Vapours 

 in Eiames 118 



Dr. Hans Schrader on the Existence of Chemical Compounds 

 of Short-lived Eadioactive Elements - 125 



Mr. Alexander S. Russell on the "Volatility of Radium C . . 131 



Dr. Charles A. Sadler and Mr. Paul Mesham on the Rontgen 

 Radiation from Substances of Low Atomic Weight 138 



Mr. Herbert E. Ives : Studies in the Photometry of Lights 

 of Different Colours. — I. Spectral Luminosity Curves ob- 

 tained by the Equality of Brightness Photometer and the 

 Elicker Photometer under similar conditions. (Plates 

 IIJ..-V.) 149 



Prof. J. A. Pollock on the Origin of the Small Bubbles of 

 Eroth. (Plates VI.-YIII.) 181) 



Prof. H. A. "Wilson on the Application of Thermodynamics 

 to the Discharge of Electricity by Hot Bodies 196 



Dr. R. D. Kleeman on c Rays. 198 



Notices respecting New Books : — 



C. Smith's Conic Sections by the Methods of Coordinate 



Geometry 202 



Prof. G. A. Gibson and Dr. P. Pinkerton's Elements of 



Analytical Geometry 202 



K. J. T. Bell's Coordinate Geometry of Three Dimen- 

 sions , •. 202 



