CONTENTS OF VOL. VI. FIFTH SERIES. VU 



Pagd 



On the Dissociation of the Oxides of the Platinum Group, by 

 H. Sainte-Claire Deville and H. Debray 394 



On a Universal Law respecting the Dilatation of Bodies, by 

 M. Levy 397 



On Diffusion as a Means of converting Normal-Temperature 

 Heat into Work, by S. Tolver Preston 400 



NUMBER XXXIX.— DECEMBER. 



Mr. Gr. J. Stoney on the Mechanical Theory of Crookes's (or 

 Polarization) Stress in Grases 401 



Prof. E. Edlund's Researches on Unipolar Induction, Atmo- 

 spheric Electricity, and the Aurora Borealis 423 



Mr. 0. Heaviside on a Test for Telegraph Lines 436 



Prof. W. C. Rontgen on Electrical Discharges in Insulators . . 438 



Prof. P. E. Chase on the Nebular Hypothesis. — X. Predictions 448 



Sir J. Conroy on the Light reflected by Potassium Permanga- 

 nate 454 



Mr. A. S. Davis on a possible Cause of the Formation of 

 Comets' Tails 459 



Notices respecting New Books : — 



Baron Rayleigh on the Theory of Sound 462 



A few Magnetic Elements for Northern India, bv R. S. 

 Brough 464 



On Molecular Attraction in its Relations with the Tempera- 

 ture of Bodies, by M. Levy 466 



Dr. T. A. Edison on the Sonorous Voltameter 468 



PLATES. 



I. Illustrative of Mr. I). .7. Blaikley's Paper on Brass Wind Instru- 

 ments as Resonators. 



II. Illustrative of Professor Ayrton's Paper on the Electrical Proper- 

 ties of Bee's- wax and Lead Chloride. 



III. Illustrative of Mr. .J. E. H. Gordon's Paper on the Effect of Varia- 



tion of Pressure on the Length of Disruptive Discharge in Air. 



IV. Illustrative of the Rev. J. F. Blake's Paper on the Measurement of 



the Curves formed by Cephalopoda and other Mollusks. 

 V. Illustrative of Mr. T. Gray's Paper on the Experimental Determi- 

 nation of Magnetic Moments in Absolute Measure. 

 VI., VII. Illustrative of Professor S. P. Thompson's Paper on Mag- 

 netic Figures illustrating Electrodynamic Relations. 

 VIII. Illustrative of Prof. E. Edlund's Paper on Unipolar Induction, 

 Atmospheric Electricity, and the Aurora Borealis. 



