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 sane textus ideo melior quia ex se fila gignunt, nee uoster 

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



VOL. IX.— FOURTH SERIES. 

 JANUARY— JUNE, 1855. 



LONDON. 



TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET, 

 Printers and Publishers to the University of London ; 



MOLD BY LONGMAN, BROWN, GREEN, AND LONGMANS; SIMPKIN, MAIISHALL 

 AND CO.; S. HIGHLEY ; WHITTAKER AND CO.; AND PIPER AND 



CO., LONDON : BY ADAM AND CHARLES BLACK, AND 



THOMAS CLARK, EDINBURGH; SMITH AND SON, 



GLASGOW; HODGES AMD SMITH, DUBLIN j 



AND WILEY AND PUTNAM, NEW YORK. 



