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THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



SIR OLIVER JOSEPH LODGE, D.Bc, LL.D., F.R.S. 



SIR JOSEPH JOHN THOMSON, M.A., Sc.D., LL.D., F.R.S 



JOHN JOLY, M.A, D.Sc, F.R.S., F.G.S. 



GEORGE CAREY FOSTER, B.A, LL.D, F.R.S. 



AND 



WILLIAM FRANCIS, F.L.S. 



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

 vilior quia ex alienis libamus ut apes." Just. Lips. Polit. lib. i. cap. 1 . Not. 



VOL. XX VIII.— SIXTH SERIES. 

 JULY— DECEMBER 1914. 



->r. ,«• > / 



DEC 17 K 



t ON DO R : 

 TAYLOR AN J) FKANClk, REfi LION COUKT. FLEET STREET. 



SOLD BY 8IJIPKIN, MARSHALL, HAMILTON. KENT. AND Co.. I I) 



SMITH AND SON. GI.AscoW :— HOOGKS, PrGGIS, AND CO., DUKLIN; 



VEUVK J. BOYVEAC. PARTS; — AND AKHER AND CO.. BERMN. 



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