IV CONTENTS OF VOL. XIV. SIXTH SERIES. 



Page 

 Proceedings of the Geological Society : — 



Mr. H. H. Arnold-Bern rose on the Toadstones of Derby- 

 shire, their Field-Belations and Petrography 213 



Prof. J. W. W. Spencer on Data bearing on the Age of 



Niagara Palls 214 



Mr. H. J. Lowe's Penological Notes on the Igneous 



Pocks lying to the South-East of Dartmoor 215 



Intelligence and Miscellaneous Articles : — 



Electrical Ionic Conductivities, by Philip Blackman . . 215 



NUMBEB LXXX.— AUGUST. 



Prof. J. J. Thomson on the Electrical Origin of the Eadiation 

 from Hot Bodies 217 



Mr. A. S. Eve and Dr. D. Mcintosh on the Amount of 

 Eadium present in Typical Bocks in the immediate Neigh- 

 bourhood of Montreal 231 



Prof. E. Taylor Jones on a Short-Period Electrometer, and 

 its use in Determining the Frequencies of Slow Electrical 

 Oscillations. (Plate IX.) 238 



Prof. J. A. Fleming on the Poulsen Arc as a means of 

 obtaining Continuous Electrical Oscillations 254 



Dr. S. Tolver Preston on Certain Questions connected with 

 Astronomical Physics. — Part II 265 



Messrs. P. Soddy and T. D. Mackenzie on the Eelation 

 between Uranium and Eadium 272 



Prof. J. J. Thomson on Eays of Positive Electricity 295 



Mr. I. O. Griffith on the Eelation between the Intensity of 

 the Ultra-Violet Light falling on a Negatively-charged Zinc 

 Plate and the Quantity of Electricity which is set free from 

 the Surface 297 



Mr. G. H. Martyn on the Discharge of Electricity from Hot 

 Bodies. (Plate X.) 306 



Prof. J. Larmor on the Eange of Freedom of Electrons in 

 Metals 312 



Notices respecting New Books : — 



E. Gerard et O. De Bast's Exercices et Projets d'Electro- 

 technique 316 



NUMBEE LXXXL— SEPTEMBEE. 



Lord Kelvin on the Motions of Ether produced by Collisions of 

 Atoms or Molecules containing or not containing Electrions. 317 



Mr. G. Le Bas on the Unit-Stere Theory : The Demonstration 

 of a Natural Eelation between the Volumes of the Atoms 

 in Compounds under Corresponding Conditions and that 

 of Combined Hydrogen 324 



