Nature 
ee NNT ESIC 
Pees tRABED JOURNAL OF SCIENCE 
VOLUME LXVI 
MAY to OCTOBER 1902 
“To the solid ground 
Of Nature trusts the mind which builds for aye.’—WorDSWOR1H 
173689 
Pondon 
Veweovunn LAN AND CO., LimitTep 
NEW YORK: THE MACMILLAN COMPANY 
