/ 





THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



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



SIR JOSEPH JOHN THOMSON, O.M., 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 rnelior quia ex se fila gignunt, nee noster 

 vilior quia ex aiienis libamus ut apes." Just. Lips. Polit. lib. i. cap. l.Not.. 



VOL. XXXII.— SIXTH SERIES, 

 JULY— DECEMBER 1916. 



1XLTZ 



. 



LONDON-. 

 TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



SOLD BY SIMPKIN, MARSHALL, HAMILTON, KENT. AND CO., LP. 

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

 AND VEUVE J. BOYVEAU, PARTS. 



