Vol. 39. FEBRUARY 1895. No. 237. 



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



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,' 

 Nicholson s 'Journal] and Thomsons l Annals of Philosophy.' 



CONDUCTED BY 



LORD KELVIN, LL.D. P.R.S. <fcc. 



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° 237.— FEBRUARY 189 



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