Vol. 34. JULY 1892. No. 206. 



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THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



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JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,' 

 Nicholson's 'Journal? and Thomsons 'Annals of Philosophy: 



CONDUCTED BY 



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GEORGE FBANCIS FITZGERALD, M.A. Sc.D. F.R.S. 



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FIFTH SERIES* 



N° 206.-JULY 1892. 



WITH TWO PLATES. 



Illustrative of Mr. 0. Baetjs's Paper on the Fusion Constants of 

 Igneous Rock, and Dr. W. Pole's on Colour-Blindness. 



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