Page:Popular Science Monthly Volume 79.djvu/7

 

THE

POPULAR SCIENCE

MONTHLY

 

 

 

 

 

 

EDITED BY

J. McKEEN CATTELL

 

 

 

 

 

 

VOL. LXXIX

 

JULY TO DECEMBER, 1911

 

 

 

 

 

 

NEW YORK
THE SCIENCE PRESS
1911