Vol. 21. JANUARY 1889.. No. 164. 



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THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



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JOURNAL OF SCIENCE. 



Being a Continuation of Tilloch^s ^Philosophical Magazine,'' 

 Nicholson^ s 'Journal,^ and Thomsons 'Annals of Philosophy.'' 



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FIFTH SERIES. 



N« 164.— JANUARY 1889. 



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Illustrative of Prof. J". A. Fleming's Paper on a Design for a Standard of 

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