Vlll CONTENTS OF VOL. XXXI. FIFTH SERIES. 



Note on the Electrical Conductivity of Hot G-ases, by Prof. 

 J. J. Thomson 515 



Propagation of Hertz's Oscillations in Air, by MM. E. Sarasin 

 and L. De la Eive 516 



On an improved Method of Determining Specific Heats by the 

 Electrical Current, by Prof. J. Pfaundler 518 



On Periodically Variable Electromotive Eorces which act only 

 in one direction in a Conductor with Self-induction, by 

 Prof. Puluj of Prag 518 



On Wheatstone's Determination of the Velocity of Elec- 

 tricity, by Prof. J. Stefan ' 519 



Index 520 



PLATES. 



I.-III. Illustrative of Mr. M. Carey Lea's Paper on Allotropic Silver. 



IV. Illustrative of Lord Rayleigh's Paper on Pin-hole Photography. 



V. Illustrative of Messrs. Boys, Briscoe, and Watson's Paper on the 

 Measurement of Electromagnetic Radiation. 



VI. Illustrative of Mr. E. B. Rosa's Paper on the Specific Inductive 

 Capacity of Electrolytes. 



VII. Illustrative of Mr. A. A. JVIichelson's Paper on the' Application 

 of Interference-Methods to Spectroscopic Measurements. 



VIII. Illustrative of Mr. W. W. J. Nicol's Paper on the Mutual 

 Solubilitv of Salts in Water. 



ERRATUM. 

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