CONTEXTS OF VOL. XIX. SIXTH SERIES. \[[ 



NUMBER CXIII.— MAY. 



Page 



Dr. A. S. Eve on the Effect of Dust and Smoke on the 



Ionization of Air 657 



Prof. J. Perry on Telephone Circuits 673 



Mr. S. C. Laws on the Change of Resistance of Metals in a 



Magnetic Field at Different Temperatures 685 



Prof. P. Lowell on the Limits of the Oblateness of a Rotating 



Planet and the Physical Deductions from them 700 



Mr. S. H. Burbury on Boltzmann's Law of Probability e~ h X .712 



Dr. Gr. C. Simpson on Earth-Air Electric Currents 715 



Mr. and Mrs. Soddy and Mr. A. S. Russell on the Question 



of the Homogeneity of y-Rays. (Plate XTI.) 



725 



Dr. J. W. Nicholson on the Bending of Electric Waves round 



the Earth 757 



Prof. H. Rubens and Mr. H. Hollnagel on Measurements in 



the Extreme Infra-Red Spectrum. (Plate XITI.) 761 



Dr. R. D. Kleeman on the Nature of the Forces of Attraction 



between Atoms and Molecules 783 



Prof. H. A. Wilson on the Relative Motion of the Earth 



and the ^Ether 809 



Mr. W. Sutherland on the Theory of the Small Ion in Gases. 817 

 Notices respecting New Books : — 



Prof. J. Joly's Radioactivity and Geology 819 



Proceedings of the Geological Society 820-823 



Intelligence and Miscellaneous Articles : — 



Correction to Mr. Bateman's Paper on the Reflexion of 

 Light at an Ideal Plane Mirror movingwith a Uniform 

 Velocity of Translation 824 



NUMBER CXIV.— JUNE. 



Mr. G. N. Antonoff on Radium I) and its Products of 

 Transformation S25 



Dr. R. D. Kleeman on the Radius of the Sphere of Action 

 of a Molecule S40 



Messrs. F. Soddy and A. S. Russell on the Constant of 

 Uranium X S47 



Mr. J. Rose-Innes on the Motion of a Pendulum swinging 

 through an Arc of Finite Magnitude 851 



Dr. B. D. Steele on an Automatic Toepler Pump, designed to 

 collect the gas from the apparatus being exhausted 863 



Dr. W. H. Bccles on Coherers 869 



Prof. A. W. Porter on the Inversion-Points for a Fiuid 

 passing through a Porous Plug and their use in Testing 

 proposed Equations of State. Part J I. An Examination 

 of Experimental Data 888 



