STol. 32. 



JULY 1891. 



No. 194. 



Published the First Day of every Month. 



THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine/ 

 Nicholson's 'Journal/ and Thomsons 'Annals of Philosophy.'' 



CONDUCTED BY 



SIR WILLIAM THOMSON, Knt. LL.D. P.R.S. Ac. 

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



AND 



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



FIFTH SERIES. 



N° 194.- JULY 1891 



LONDON: 



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