JANUARY 1865. No. 193, 



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 Jilloch's 'Philosophical Magazine/ 

 Nicholson's 'Journal,' 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° 193.— JANUARY 1865. 



WITH A PLATE, 



Illustrative of Dr. Rankine's Papers on the approximate Graphic Mea- 



surement of Elliptic and Trochoidal Arcs ; and on Stream-lines. 



LONDON: 



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



Printers and Publishers to the University of London. 

 Sold by Longman, Green, Longmans, *nd Roberts; Piper and Co.; Simpkin, 

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