﻿61. 37. MAY 1869. No. 250. 



Published the First Day of every Month. — Price 2.5. 6d. 



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloch's 'Philosophical Magazine? 

 Nicholson's 'Journal, 9 and Thomson's 'Annals of Philosophy.' 



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

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AND 



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



FOURTH SERIES. 



N° 250.— MAY 1869. 



LONDON: 



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