Vol 33. APRIL 1892. No. 203. 



Published the First Day of every Month, — Price 2s. Qd. 



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloctis l Philosophical Magazine,' 

 Nicholsons 'Journals and Thomson s l Annals of Philosophy. ,' 



CONDUCTED BY 



LORD KELVIN, LL.D. P.R.S. Ac. 



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 SEME 



N° 203.— APRIL 1892. 



LONDON: 



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