

THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



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. 



" Nee araneamm sane textus ideo melior quia ex se fila gignunt, nee noster 

 vilior quia ex alienis libamus ut apes." Just. Lips. Polit. lib. i. cap. 1 . Not. 



VOL. XXXIV.— FOURTH SERIES, 

 JULY— DECEMBER, 1867. 



LONDON. 



TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET, 

 Printers and Publishers to the University of London ; 



SOLD BY LONGMANS, GREEN, READER, AND DYER ; SIMPKIN, MARSHALL AND CO. 



WHITTAKER AND CO.; AND KENT AND CO., LONDON: — BY ADAM AND 



CHARLES BLACK, AND THOMAS CLARK, EDINBURGH 



SMITH AND SON, GLASGOW; HODGES AND 



SMITH, DUBLIN ; AND PUTNAM, 



NEW YORK. 



