VI CONTENTS OF VOL. V. SIXTH SERIES. 



NUMBER XXVIII.— APEIL. 



Page 

 Prof. J. S. Townsend on the Conductivity produced in Cases 



by the Aid of Ultra-Violet Light. (Plate IX.) 389 



Mr. S. W. J. Smith on a Portable Capillary Electrometer. 



(Plate X.) 398 



Dr. Meyer Wilderman on the Connexion between Ereezing- 



points, Boiling-points, and Solubilities 405 



Prof. J. C. McLennan on Induced Radioactivity Excited in 



Air at the Eoot of Waterfalls " 419 



Mr. H. A. Wilson: Determination of the Charge on the 



Ions produced in Air by Rontgen Rays 429 



Prof. E. Rutherford and Mr. E. Soddy on the Radioactivity 



of Uranium 441 



Prof. E. Rutherford and Mr. E. Soddy : Comparative Study 



of the Radioactivity of Radium and Thorium 445 



Mr. H.W. Chapman on the Problem of Columbus. (Plate XL) 458 

 Messrs. C. Ruuge and J. Precht on the Position of Radium 



in the Periodic System according to its Spectrum . . 476 



Prof. E. Rutherford on Radioactivity 481 



Dr. Quirino Majorana on New Magneto-Optic Phenomena 



exhibited by Magnetic Solutions 486 



Prof. L. R. Wilberforce on an Elementary Treatment of 



Conducting Networks 489 



Notices respecting New Books : — 



Kavasji Dadabhai Naegamvala's Report on the Total 

 Solar Eclipse of January 21-22, 1898, as observed at 



Jeur in Western India 490 



Dr. A. von Waltenhofen's Die Internationalen Absoluten 

 Masze Insbesondere die Electrischen Masze, fiir Studi- 



rende der Electrotechnik 491 



E. M. Raoult's Cryoscopie 492 



Bericht iiber die Internationale Experten-Conferenz fiir 

 Wetterschiessen in Graz . < 492 



NUMBER XXIX.— MAT. 



Prof. J. A. Fleming and Mr. W. C. Clinton on the Measure- 

 ment of Small Capacities and Inductances. (Plate XII.) . 493 



Mr. J. W. Peck on the Special Epochs in Vibrating Systems. 511 



Dr. Gr. J. Parks on the Thickness of the Liquid Film formed 

 by Condensation at the Surface of a Solid . 517 



Prof. J. Trowbridge on the Caseous Constitution of the H 

 and K lines of the Solar Spectrum, together with a Dis- 

 cussion of Reversed Gaseous Lines. (Plate XIII.) 521 



Mr. V. J. Blyth on the Influence of Magnetic Field on 

 Thermal Conductivity 529 



