pit es 
Nature, , } 
March 15, 1917 
Nature ~ 
A WEEKLY 
ILLUSTRATED JOURNAL OF SCIENCE 
VOLUME XCVIII 
SEPTEMBER, 1916, to FEBRUARY, 1917. 
“To the solid ground 
Of Nature trusts the mind which builds for aye.”—WoRDSWORTH 
#ondon 
MAIGCMLLEULAN AN D GO} ckimitrEen 
NEW YORK: THE MACMILLAN COMPANY 
