Vol. 28. NOVEMBER 1889. No 174 



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 Tilloclis i Philosophical Magazine' 

 Nicholson's l Journal / and Thomson's l Annals of Philosophy.' 



CONDUCTED BY 



SIR ROBERT KANE, LL.D. F.R.S. M.R.I.A. F.C.S. 

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



AND 



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



FIFTH SERIES. 



No 174.— NOVEMBER 1889. 



WITH THREE PLATES. 



Illustrative of Messrs. Threlfall and Pollock's Paper on the Clark 

 Cell as a Source of small Constant Currents ; and Prof. E. Threlfall's 

 on the Application of the Clark Cell to the Construction of a Standard 

 Galvanometer. 



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