Vol. 33. 



MARCH 1867. 



No. 222. 



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 TillocKs 'Philosophical Magazine? 

 Nicholson's e Journal, 9 and Thomson's ( Annals of Philosophy. 9 



CONDUCTED RY 



SIR DAVID BREWSTER, K.H. LL.D. F.R.S. L.&E. &c. 

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

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



FOURTH SERIES 



N° 222.— MARCH 1867. 



LONDON: 



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



Printers and Publishers to the University of London. 



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

 Co. ; Whittaker and Co. ; andH. Bailliere, London :— and by A. and C. Black, and 

 Thomas Clark, Edinburgh; Smith and Son, Glasgow: — Hodges and Smith, 

 Dublin : — and Putnam, New York. 



