36. OCTOBER 1893? Va f No. 221 



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THE 

 LONDON, EDINBURGH, and DUBLIN 



^ILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloctis 'Philosophical Magazine,' 

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



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FIFTH SERIES* 



N° 221.— OCTOBER 1893. 



WITH ONE PLATE. 



Illustrative of Mr. John Trowbridge's Paper on the Oscillations of 

 Lightning Discharges and of the Aurora Borealis. 



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