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, 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. 



n 



" Nee aranearum sane textus ideo melior quia ex se fila gignunt, nee noste? 

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



VOL.'XXI:— feXTH" SERIES, 



. L ' JANUARY— JUNE 1911. * 



LONDONt 

 TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



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



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



VEUVE J. BOYYEAU, PAftIS | — AND ASlIER AND CO., Bfl&UK. 



390 



