Vol. 39. 



APRIL 1895. 



No. 239. 



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



THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



A2J.D 



JOURNAL OF SCIENCE, 



Being a Continuation of Tilloctis l Philosophical Magazine/ 

 Nicholson's 'Journal,' and Thomson's { 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 SERIFS. 



N° 239.— APRIL 1895. 



LONDON: 



PBINTED BY TAYLOR AND FBANCIS, BKD LION COUBT, FLEET STREET. 



Sold by Simp kin, Marshall, Hamilton, Kent, and Co., Ld.; Whittaker and Co.; 

 and by A. and C. Black ;— T. and T. Olark, Edinburgh . Smith and Son, 

 Glasgow: — Hodges, Figgis, and Co., Dublin: — Putnam, New York: — Veuve J. 

 Boyveau, Paris : — and Asher and Co., Berlin. 



