6 oj 



CHIEF CL-V? J 

 Vol. 30. SE PTEMBER bSSfl. No. 184 



Published the First Day of every Month, — Price 2s. 6d. 



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of TillocJis 'Philosophical Magazine' 

 Nicholson's c Journal ,' and Thomson's c Annals of Philosophy' 



CONDUCTED BY 



SIR WILLIAM THOMSON, Knt. LL.D. F.R.S. Ac. 

 GEORGE FEANCIS FITZGERALD, M.A. F.R.S. 



AND 



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



FIFTH SERIES. 



N» 184.— SEPTEMBER 1890. 



WITH ONE PLATE. 



Illustrative of Prof. C. V. Boys's Paper on Photographs of Eapidly 

 Moving Objects, and on the Oscillating Electric Spark. 



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