The Popular Science Monthly 



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



CONTENTS OF MARCH NUMBER 



The Physiography of the Adirondacks. Professor 



James Fukman Kemp. 

 The Black Locust Tree and its Despoliation. Dr. 



Charles A. White. 

 A Contribution to the Theory of Science. Professor 



WjLHELM OSTWALD. 



The Jewsharp. The late Dr. H. Carrington 



Bolton. 

 Geological History of Cockroaches. Dr. E. H. 



Sellards. 

 How Rooting Aquatic Plants Influence the Nutrition 



of the Food Fisnes of Great Lakes. Professor 



Raymond Pond. 

 Urban and Rural Life. Frank T. Carlton. 

 Newspaper Football. Professor Edwin G. Dexter. 

 Submarine Navigation. Sir William H. White. 

 Trial aDd Error as a Factor in Evolution. Professor 



W. B. Pillsbury. 

 The Progress of Science : 



The Rewards of Scientific Research ; The Work 



of the Carnegie Institution ; Professor Adolf 



von Baeyer ; Scientific Items. 



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. 



MacBbide. 

 Extra Digits and Digital Reductions. Dr. Chables 



W. Prentiss. 

 A Sanitary Outlook. Sib James Cbichton - Brown. 

 Shorter Articles : 



The Yellow Fin Albacore : President David 



Stabr 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. 



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