Vol. 35. JANUARY 1893. No. 212. 



Published the First Day of every Month.-^Price 2s. 6d. 



THE ' 



LONDON, EDINBURGH, and DUBLIi>h>V 



PHILOSOPHICAL MAGAZINE. 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,' 

 Nicholson s 'Journal? and Thomson s 'Annals of Philosophy.'' 



CONDUCTED BY 



LORD KELVIN, LL.D. P.R.S. &c. 



GEORGE FRANCIS FITZGERALD, M.A. Sc.D. F.R.S, 



AND 



WILLIAM FRANCIS, Ph.D. F.L.S. F.R.A.S. F.C.S. 



FIFTH SERIES. 



N° 212.— JANUARY 1893. 



WITH FOUR PLATES. 



Illustrative of Professor Threleall's Paper on the Electrical Properties 

 of Pure Nitrogen ; Messrs. Rubens and Snow's on the Refraction 

 of Rays of Great Wave-length in Rock-salt, Sylvite, and Fluorite ; 

 Mr. F. Saneord's on a necessary Modification of Ohm's Law ; and 

 Messrs. Rimington and Wythe Smith's on Experiments in Electric 

 and Magnetic Fields, Constant and Varying. 



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