THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



LORD KELVIN, LL.D. P.R.S. &c. 

 GEORGE FRANCIS FITZGERALD, M.A. Sc.D. F.R.S. 



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 libaraus ut apes." Just. Lips. Polit. lib. i. cap. 1 . Not. 



VOL. XXXIX.— FIFTH SERIES. 

 JANUARY— JUNE 1895. 



LONDON: 

 TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



SOLD BY SIMPKIN, MARSHALL, HAMILTON, KENT, AND CO., LD.', WHITTAKER AND CO. ; 

 AND BY ADAM AND CHARLES BLACK J — T. AND T.CLARK, EDINBURGH; 



SMITH AND SON, GLASGOW; — HODGES, FIGGIS, AND CO., DUBLIN; 



PUTNAM, NEW YORK; — VEUVE J. BOYVEAU, PARIS ', — 

 AND ASHER AND CO., BERLIN. 



