Vol. 24. DECEMBER 1887. No. 151 



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

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THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,' 

 Nicholson's ' Journal f and Thomson s 'Annals of Philosophy,'* 



CONDUCTED BY 



SIR ROBERT KANE, LL.D. F.R.S. M.R.LA. F.C.S. 

 SIR WILLIAM THOMSON, Knt. LL.D. F.R.S. <fcc. 



AND 



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



FIFTH SERIES. 



N° 151.— DECEMBER 1887. 



LONDON: 



PRINTED BY TAYLOB AND FBANCIS, BED LION COUBT, FLEET 8TBEET. 



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