Nature, 
October 7, 1915 
Nature 
AY WEEKLY 
PST RATED JOURNAL OF SCIENCE 
VOLUME} XCV 
MARCH, 1915, to AUGUST, 1915. 
“To the solid ground 
Of Nature trusts the mind which builds for aye.”.—WoRDSWORTH 
London 
NieAnGa\V else A Nts vAGNe Dr G © hemlet 2p 
NEW YORK: THE MACMII LAN COMPANY 
