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. 

 RICHARD TAYLOR, F.L.S. G.S. Astr. S. Nat. H. Mosc. &c. 

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

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

 JOHN TYNDALL, Ph.D. F.R.S. &c. 



" Nee aranearum saue textus ideo melior quia ex so flla gignunt, iiec uoster 

 vilior quia ex alienis libaraus ut apes." Just. Lips. PoUt. lib. i. cap. 1. Not. 



VOL. VII.— FOURTH SERIES. 

 .JANUARY— JUNE, 1854. 



LONDON. 



TAYLOR AND FRANCIS, UEU LION COURT, FLEET STREET, 



Printers and Publishers to the University of London j 



sOI.U BY LONGMAN, BllOWN, GRKEN, AND LONGMANS; SIMPKIN, MARSHALL 

 AND CO.; S. HIGHLEY ; WHITTAKEll AND CO.; AND PIPEII AND 



CO., LONDON: IIY ADAM AND CUAKLES liLACK, AND 



THOMAS CLARK, EDINBURGH; SMITH AM) SON, 



GLASGOW; HODGES AND SMITH, Dl.'lil.; N ; 



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