Vol. 26. SEPTEMBER 1888." No. 160. 



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



<?<3 ' 



V-: 10 1888/ THE 



• LONDON, EDINBURGH, and DUBLIN 



"^PHILOSOPHICAL MAGAZINE, 



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JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine,'' 

 Nicholson s 'Journal? and Thomson's ( Annals of Philosophy.' 



CONDUQTED 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. 



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



FIFTH SERIES. 



K« 160.— SEPTEMBER 1888. 



WITH TWO PLATES. 



Illustrative of Mr. J. Jolt's Paper on a Hydrostatic Balance, and Dr. 

 E. H. Cook's on the Existence of an Undulatory Movement accom- 

 panying the Electric Spark. 



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