Vol. LXXVin, No. 4 APRIL, 1911 



THE 



POPULAR SCIENCE 

 MONTHLY 



EDITED BY J". McKEEX CATTELL 



CONTENTS 



The Genesis of the Law of Gravity. Professor John C. Shkdd . . 313 



Edward Palmer. "William Edward Saffobd 341 



Freud's Theories of the Unconscious. Professor William Chasb . . 355 



Impressions of Military Life in France. Professor Albert Leon Quebabd 364 



Eeality and Truth. Professor T. D. A. Cockebell .... 371 



The Cost of Living. Professor Henry Pbatt Faibchild . . .377 



Alcohol — Its Use and Abuse : Professor Graham Lusk .... 381 



Scientific versus Personal Distribution of College Credits. President 

 William T. Fosteb 389 



The Progress of Science : 



The Population of the United States in 1910 ; The Reaearoh Work of the Carnegie 

 Institution ; The House of Asa Gray ; Soientifio Items ..... 409 



THE SCIENCE PRESS 



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NEW YORK: Sub-Station 84 

 Single Number, 30 Cents Yearly Subscription, $3.00 



Copteiqht, 1910, BT THE SCIENCE PBESS 



