Vol.5. JUNE 1878. No. 33. 



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 'Philosophical Magazine? 

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



CONDUCTED BY 



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



N° 33.— JUNE 1878. . ^ 



LONDON: 



PBLNTED BY TAYLOB AND FBANCIS, BED LION COUBT, FLEET STBEET, 



Sold by Longmans, Green, Reader and Dyer; Kent and Co. ; Simpkin, Marshall and 

 Co. ; and Whittaker and Co. j — and by A. and C. Black, and Thomas Clark, Edin- 

 burgh ; Smith and Son, Glasgow : — Hodges, Foster, and Co., Dublin : — Putnam, 

 New York : — and Asher and Co., Berlin. 



