CONTENTS OF VOL. XLIX. 



(FIFTH SEEIES). 



NUMBER CCXCVL— JANUAEY 1900. 



Page 

 Prof. E. Eutherf ord on a Eadio-active Substance emitted from 



Thorium Compounds 1 



Mr. B. Osgood Peirce on the Thermal Conductivity of 



Vulcanite 15 



Dr. Charles Davison on Earthquake-Sounds , 31 



Mr. Frederick S. Spiers on Contact Electricity 70 



Mr. T. G. Bedford on the Expansion of Porcelain with Eise 



of Temperature 90 



Lord Eayleigh on the Law of Partition of Kinetic Energy . . 98 

 Dr. C. G. Knott on Swan's Prism Photometer, commonly 



called Lummer and Brodhun's Photometer 118 



Dr. S. W. Eichardson on the Magnetic Properties of the 



Alloys of Iron and Aluminium. — Part 1 121 



Proceedings of the Geological Society : — 



Mr.H. Lapworth on the Silurian Sequence of Bhayader. 155 

 Dr. Blanford on Photographs representing the Dwyka 



Boulder-Bed 156 



Dr. J. W. Gregory on the Geology and Fossil Corals and 



Echinids of Somaliland 157 



Mr. G. Clinch on Drift-Gravels at West "Wickham 



_ (Kent) 157 



Intelligence and Miscellaneous Articles : — 



On Kerr's Phenomenon, by MM. Abraham and Lemoine 158 

 Obituarv Notice : Dr. J. L. Howard 1 GO 



