ol.l8. JULY 1884. No. 110. 



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



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE. 



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JOURNAL OF SCIENCE. 



Being a Continuation of Tilloctis 'Philosophical Magazine? 

 Nicholson's ' Journal f and Thomson s 'Annals of Philosophy' 



CONDUCTED BY 



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

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



FIFTH SERIES. 



N° 110.-JULY 1884. °-^ 



WITH FOUK PLATES. 



Illustrative of Prof. Caenelley's 'Paper on the Periodic Law, Prof. E. 

 Wiedemann's on the Electric Discharge in Gases, Profs. Ayeton and 

 Peeet's on the Gas-Engine Indicator-Diagram, and Sir A. Campbell 

 and Mr. W. T. Goolden's on a " Speed Indicator " for Ships' 

 Propellors. 



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