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. 
“ Nec aranearum sane textus ideo melior quia ex se fila gignunt, nec nosier 
vilior quia ex alienis libamus ut apes.” Just. Lips. Monit. Polit. lib. i. cap. l. 
VOL. XVI. 
NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE, 
ANNALS OF PHILOSOPHY, AND JOURNAL OF SCIENCE. 
JANUARY— JUNE, 1840. 
LONDON: 
RICHARD AND JOHN E. TAYLOR, RED LION COURT, FLEET STREET, 
Printers and Publishers to the University of London; 
SOLD BY LONGMAN, ORME, BROWN, GREEN, AND LONGMANS; CADELL; 
SIMPKIN AND marshall; S. HIGHLEY ; WHITTAKER AND CO.; AND 
SHERWOOD, GILBERT, AND PIPER, LONDON : BY ADAM AND 
CHARLES BLACK, AND THOMAS CLARK, EDINBURGH ; SMITH 
AND SON, GLASGOW ; HODGES AND SMITH, DUBLIN : 
AND G. W. M. REYNOLDS, PARIS. 
