3 THE «-* ■ 



/ o 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



LORD KELVIN, G.O.V.O. D.C.L. LL.D. F.R.S. fto. 

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



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



" Nee aranearutn 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. XLVIIL— FIFTH SERIES. 

 JULY— DECEMBER 1899. 



LONDON: 

 TAYLOR AND FRANCIS, EED LION COURT, FLEET STREET. 



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



AND BY ADAM AND CHAELES BLACK; T. AND T.CLARK, EDINBURGH; 



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



PUTNAM, NEW YORK, VEUVE J. BOYVEAU; PARI3 J — 



AND ASHER AND CO r , BERLIN. 



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