THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



SIR ROBERT KANE, LL.D. F.R.S. M.R.I.A. F.C.S. 

 SIR WILLIAM THOMSON, Knt. LL.D. F.R.S. &c. 



AND 



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





" Nee aranearum 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. VIL— FIFTH SERIES. 

 JANUARY— JUNE 1879. 



g 



fyioi^ 



LONDON: 

 TAYLOE AND FEANCIS, EED LION COUET, FLEET STEEET. 



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



AND CO. J AND wniTTAKER AND CO. ; AND BY ADAM AND CHARLES BLACK, 



AND THOMAS CLARK, EDINBURGH ; SMITH AND SON, GLASGOW J — 



HODGES, FOSTER, AND CO., DUBLIN; — PUTNAM, NEW 



YORK ; — AND ASHER AND CO., BERLIN. 



