IV CONTENTS OF VOL. XIII. SIXTH SERIES. 



Page 

 Mr. J. M. Baldwin on the Behaviour of Iron under Small 



Periodic Magnetizing Forces. (Plate VII.) 232 



Mr. A. S. Eve on the Ionization of the Atmosphere over the 



Ocean 248 



Dr. J. "W. Nicholson on a General Solution of the Electro- 

 magnetic Relations 259 



Dr. A. Wood and Mr. N. It. Campbell on Diurnal Periodicity 

 of the Spontaneous Ionization of Air and other Gases in 



Closed Vessels 265 



Dr. P. E. Shaw on Spark Potentials in Liquid Dielectrics . . 277 

 Mr. L. de la Eive on the Introduction of Doppler's Eactor 



into the Solution of the Equations of the Electron Theory. 279 

 Prof. J. H. Jeans on the Thermodynamic^ Theory of 



Eadiation 285 



Notices respecting New Books : — 



E. E. Eournier d'Albe's The Electron Theory 286 



Dr. H. Woods's ^Ether: a Theory of the Nature of 



iEther and its Place in the Universe 287 



Proceedings of the Geological Society : — 



Mr. E. A. Newell Arber on the Upper Carboniferous 



Eocks of West Devon and North Cornwall 287 



Dr. H. S. Washington on the Titaniferous Basalts of 

 the Western Mediterranean 288 



NUMBEE LXXV.— MAECH. 



Eev. P. J. Kirkby : Chemical Effects of the Electric 



Discharge in Barefied Hydrogen and Oxygen 289 



Lord Kelvin : An Attempt to explain the Eadioactivity of 



Eadium 313 



Lord Eayleigh's Acoustical Notes. (Plate VIII.) , 316 



Prof. W. H. Bragg on the Ionization of Various Gases by 



the a particles of Eadium. — No. 2. (Plate IX.) 333 



Dr. Carl Barus on the Efficiency of the Plug-Cock Fog- 



Chamber 357 



Prof. K. Pearson on the Influence of Past Experience on 



Euture Expectation 365 



Dr. G. A. Blanc on the Eadioactive Matter in the Earth and 



the Atmosphere 378 



Prof. J. Joly on Pleochroic Halos 381 



Notices respecting New Books : — 



Prof. Petrovitch's La Mecanique des Phenomenes fondee 



sur les Analogies 383 



T. J. FA. Brora wich's Quadratic Forms and their 



Classification by means of Invariant Factors 384 



Annuaire du Bureau des Longitudes pour l'An 1907 . . 384 



