Vol. 29. MAY 1890. No. 180. 



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



THE 

 LONDON, EDINBURGH, md DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,' 

 Nicholson s 'Journal J and Thomson s l Annals of Philosophy,'* 



CONDUCTED BY 



SIR WILLIAM THOMSON, Knt. LL.D. F.R.S. &c. 

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



AND 



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



FIFTH SERIES. 



N° 180.-MAY 1890. 



WITH ONE PLATE. 

 Illustrative of Rev. F. J. Smith's Paper on a New Form of Electric 



Chronograph. 



LONDON: 



PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



Sold by Kent and Co. ; Simpkin, Marshall, and Co. ; and Whittaker and Co.; — 

 and by A. and C. Black, and T. and T. Clark, Edinburgh ; Smith and Son, 

 Glasgow: — Hodges, Figgis, and Co., Dublin: — Putnam, New York : — Veuve J. 

 B oyyeau, Paris : — and Asher and Co., Berlin. 



