i 



Vol. LXXXIV, No. 4 APRIL, 19H 



THE 



POPULAR SCIENCE 



MONTHLY 



EDITED BY J. McKEEN GATTELL 1 ^ l l s P * « Y ; 



CONfENTS 



Fresh Air. Professor Frederic S. Lee 313 



Nature Play. Professor Charles Lincoln Edwards .... 330 



Kecent Developments in Weights and Measures in the United States. 



Louis A. Fischer 345 



The Struggle for Equality in the United States. Professor Charles F. 



Emerick 370 



Eugenics and Euthenics. Professor Maynard M. Metcalp . . . 383 



The Psychological Limit of Eugenics. Professor Herbert Adolphtjs 



The Kacial Origin of Successful Americans. Dr. Frederick Adams 

 Woods 397 



Darwin and Wallace on Sexual Selection and Warning Coloration. Pro- 

 fessor F. H. Pike 403 



The Progress of Science : 



Mortality Statistics of the United States; The Work in Terrestrial Magnetism of 

 the Carnegie Institution; Scientific Items . . . . . . .411 



THE SCIENCE PRESS 



LANCASTER, PA. GARRISON, N. Y. 



NEW YORK : Sub-Station 84 

 Single Number, 80 Cents Yearly Subscription, $3.00 



Copykight, 1913. by THE SCIENCE PRESS 



