PROCEEDINGS 



OF THE 



American Philosophical Society 



HELD AT PHILADELPHIA 



FOR PROMOTING USEFUL KNOWLEDGE 

 Vol. LVI. 1917. No. 4. 



CONTENTS 



Growth and Imbibition. By D. T. MacDougal and H. A. Spoehr . 289 



Spontaneous Generation of Heat in Recently Hardened Steel. By 



Charles F. Brush 353 



The Effects of Race Intermingling-. By Charles B. Davenport . . 364 



PHILADELPHIA 

 THE AMERICAN PHILOSOPHICAL SOCIETY 



104 South Fifth Street 

 1917 



