Vol. LXIV. No. 6 APRIL, 1904 



THE 



POPULAR SCIENCE 

 MONTHLY 



EDITED BY J. McKEEJ^ CAT TELL 



CO NTKNXS 



Recent Discoveries in Radiation and their Significance. PROFESspR R. 



A. MiLLIKAN 481 



Evolution of the Human Form. Charles Morris ....... 500 



The Arequipa Station of the Harvard Observatory. Professor Solon 

 I. Bailey 510 



The Royal Prussian Academy of Science and the Fine Arts, Berlin. 



Edward F. Williams 523 



The Influence of Liebig on the Development of Chemical Industries. 

 Dr. Carl Duisberg 533 



The Conservation of Energy in those of Advancing Years. Dr. Madi- 

 son J. Taylor - . 541 



The Caucasian in Brazil. Thomas C. Dawson 550 



The Air of the Luray Caverns. Dr. Guy L. Hunner 557 



The Progress of Science : 



The Centenary of the Death of Priestley; Professor Edaard Zeller ; Charles Emerson 

 Beecher ; Science at Colorado College ; The Size of Families of College Graduates ; 

 The Study of the Sciences and of Latin in the Secondary Schools 565 



Index to Volume LXIV 573 



THE SCIENCE PRESS 



LANCASTER, PA. GARRISON, N. Y. 



NEW YORK : Sub-Station 84 

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