THE 

 LONDON AND EDINBURGH 



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. 



AND 



RICHARD PHILLIPS, F.R.S. L.&E.F.G.S. &c. 



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

 vilior quia ex alienis libamus ut apes." Just. Lips. Monit. Folit. lib. i. cap. 1. 



VOL. XIL 



NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE, 

 ANNALS OF PHILOSOPHY, AND JOURNAL OF SCIENCE. 



JANUARY— JUNE, 1838. 



LONDON: 



PRINTED BY R. AND J. E. TAYLOR, RED LION COURT, FLEET STREET 



sold by longman, orme, brown, green, and longmans; cadellj 



baldwin and cradock; sherwood, gilbert, and piper; simpkin 



and marshall; whittaker and co.; and s. highley, 



London: — by adam and charles black, and 



thomas clark, edinburgh ; smith and son, 



glasgow; hodges and smith, dublin ; 



and g. w. m. reynolds, paris. 



