CONTENTS OF VOL. rVT5 



(SIXTH SERIES). 



r* * 





<. si 



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NUMBER XIX.— JULY 1902. X. O, 



Page 



Prof. E. .Rutherford and Miss H. T. Brooks on the Comparison 

 of the Radiations from Radioactive Substances 1 



Prof. C. Barus on the Sizes of the Water Particles producing 

 the Coronal and the Axial Colours of Cloudy Condensation. 24 



Mr. J. J. E. Durack on Lenard Rays ' 29 



Prof. H. Nagaoka and Mr. K. Honda on the Magnetostriction 

 of Steel, Nickel, Cobalt, and Nickel-Steels 45 



Mr. Will. C. Baker on the Hall Effect in Gold for Weak 

 Magnetic Fields 72 



Dr. W. X. Hartley on the Composition of Brittle Platinum . . 84 



Prof. W. Yoigt on the Behaviour of Pleochroitic Crystals 

 along Directions in the Neighbourhood of au Optic Axis. . 90 



Hon. R. J. Strutt on the Discharge of Positive Electrification 

 by Hot Metals , 98 



Dr. J. H. Vincent on a General Numerical Connexion 

 between the Atomic Weights. (Plates I. & II.) 103 



Prof. J. P. Kuenen and Mr. W. G. Robson on Mixtures with 

 Maximum or Minimum Vapour-Pressure 11G 



M. W. de Nicolaieve on a New Reaction between Electro- 

 static Tubes and Insulators, and on the Electrostatic Eield 

 round an Electric Current, and the Theory of Professor 

 Poynting ! 133 



Lord Kelvin on Molecular Dynamics of a Crystal 139 



Prof. John Trowbridge on Spectra arising from the Dis- 

 sociation of Water Vapour and the Presence of Dark Lines 

 in Gaseous Spectra. (Plate III.) 156 



Dr. H. S. Carslaw on a Problem in Conduction of Heat .... 162 



Prof. J. D. Everett : Contributions to the Theory of t he- 

 Resolving Power of Objectives 166 



Notices respecting New Books : — 



C. Wolfs Histoire de l'Observatoire de Paris de sa 



fondation a 1793 171 



W. G. Rhodes's Elementary Treatise on Alternating 

 Currents 173 



