V <>1- 34. OCTOBER 1867. No. 230. 



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 Tilloch's 'Philosophical Magazine, 9 

 Nicholson's 'Journal/ and Thomson's 'Annals of Philosophy. 9 





(* 



CONDUCTED I»Y 



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° 230.— OCTOBER 1867. 



LONDON: 



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



Printers and Publishers to the University of London. 

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

 Co. j Whittaker and Co. j 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. 



