)1. 38. SEPTEMBER 1869. No. 254. 



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THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



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 Nicholsons ' Journal J 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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FOURTH SERIES. 

 N° 254.— SEPTEMBER 1869. 



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