^ ICS1SX 



V\0 THE b-rjh 



r 



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 raelior quia ex se fila gignunt, noe noster 

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



VOL. XXXVI.— SIXTH SERIES. 

 JULY— DECEMBER 1918. 



[ r^o ( 



LONDON: 

 TAYLOR AND FRANCIS, RED LION COURT. FLEET STREET. 



SOLD HY BlMPKIK, MARSHALL, HAMILTON, KENT, AND CO., LD. 



SMITH AND 8 DN, GLASGOW ;— HODGES, FIGGIS, AND CO., DUBLIN; 



AND VEUVE J. BOYVEAU, PARIS. 



