The Popular Science Monthly 



Entered in the Post Office in Lancaster, Pa., as second-class matter. 



CONTENTS OF APRIL NUMBER 



Samuel Pierpont Langley, Frontispiece. 



The Queen Ant as a Psychological Study. Dr. 



William Morton Wheeler. 

 The Development of the Glacial Hypothesis in 



America. Dr. George P. Merrill. 

 The Earliest Predecessors of Copernicus. Dr. 



Charles R. Eastman. 

 The Greatest Need in Research. Prof. M. V. O'Shea. 

 Making Geography While You Wait. Thomas H. 



MacBride. 

 Extra Digits and Digital Reductions. Dr. Charles 



W. Prentiss. 

 A Sanitary Outlook. Sir James Crichton - Brown. 



Shorter Articles : 



The Yellow Fin Albacore : President David 

 Starr Jordan. 



The Progress of Science : 



Samuel Pierpont Langley ; The Solar Observa- 

 tory of the Carnegie Institution ; The Warren 

 Museum of Natural History ; The Population of 

 the United States ; The New Zoological Museum 

 and Laboratories of the University of Liverpool; 

 Scientific Items. 



CONTENTS OF MAY NUMBER 

 Watkins Glen and Other Gorges of the Finger Lake 

 Region of Central New York. Professor Ralph 

 S. Tarr. 



A League of Peace. Andrew Carnegie. 



The Body's Utilization of Fat. Dr. Frank S. 

 Mathews. 



National Control of Introduced Insect Pests. Pro- 

 fessor E. Dwight Sanderson. 



Individual Adaptation to Environment. Professor 

 Joseph Hershey Bair. 



The Disease and the Remedy. Dr. Alfred E. P. 

 Rockwell. 



The Psychology of Yellow. Havelock Ellis. 



Bird Photography in Norway. Dr. R. W. Shufeldt. 



The Progress of Science : 



The Niagara Problem under Legislation ; The 

 Report of the President of Harvard University ; 

 The Growth of the State Universities ot the Cen- 

 tral West ; The Tomb of James Smithson ; Scien- 

 tific Items. 



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