﻿VI CONTEXTS OF VOL. XXIII. SIXTH SERIES. 



Page 



Prof. H. A. Wilson on the Theory of Spectral Series 660 



Mr. C. G. Darwin on the Effects of the Diurnal Eotation on 



the Upper Atmosphere 664 



Dr. Norman Campbell on the Electrical Eesistance of Xylol- 



Alcohol Mixtures 668 



Dr. T. S. Taylor : A Determination of the Number of Ions 



produced by an Alpha Particle from Polonium 670 



Prof. J. S. Townsend : The Charges on Ions 677 



Prof. H. L. Callendar on the Absolute Expansion of Mercury. 



Eeply to Criticisms by Scheel and Heuse 679 



Dr. A. S. Eve and Mr. E. H. Day on the Absorption of 



Eontgen Bays in Air 683 



Dr. Norman Campbell : Non-Newtonian Mechanics 688 



NUMBEE CXXXVIL— MAY. 



Prof. E. W. Wood on Selective Beflexion, Scattering and 

 Absorption by Eesonating Gas Molecules. (Plates 

 X.-X1L) 689 



Prof. E. M. Wellisch and Prof. H. L. Bronson on the Distri- 

 bution of the Active Deposit of Eadium in an Electric 

 Eield 714 



Mr. Harry C. Jones on Absorption Spectra and the Solvate 

 Theory of Solution 730 



Mr. Eobert G. Lunnon on the Unilateral Conductivity of 

 Sulphated Accumulator Plates 742 



Prof. Henry A. Erikson on the Eecombination of Ions in 

 Carbon Dioxide and Hydrogen at Different Temperatures . 747 



Prof. A. Anderson and Mr. H. N. Morrison on Electric Cur- 

 rents in Air at Atmospheric Pressure, with Eemarks on 

 Induced Contact Electromotive Forces 750 



Prof. J. P. Kuenen on the Deduction of Thermodvnamical 

 Eelations ' 752 



Dr. E. B. Ludlam on the Action of Ultra-Yiolet Light on 

 Chlorine 757 



Mr. J. H. C. Searle on the Problem of the Weir . . 772 



Dr. L. Silberstein on the Quaternionic Eorm of Relativity . . 790 



Mr. Andrew Stephenson on the Propagation of Periodic 

 ^Ether Disturbance 809 



Mr. V. E. Pound on the Secondary Eays excited in the Alpha 

 Eays from Polonium 813 



Messrs. E. W. B. Gill and E. B. Pidduck on Ionization by 

 Collision in Helium 837 



Dr. Carl Eamsauer : Eemarks on the Production of Con- 

 densation Nuclei in Air and in Vapours by Intense 

 Cooling and by Ultra-Yiolet Light * 849 



Prof. W. A. Douglas Eudge : A Note on the Electrification 

 of the Atmosphere and Surface of the Earth 852 



Prof. J. S. Townsend : Theory of Ionization by Collision . . 856 



