Vol 35. 



JANUARY 1868. 



No. 234 



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,' 

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



CONDUCTED BY 



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° 234.— JANUARY 1868. 



[The Supplement to Volume 34 will be issued with the Number for 



February.] 



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. ; 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. 



