THE RELATIVE VALUE 



OF THE 



PROCESSES CAUSING 

 EVOLUTION 



BY 



AREND L. HAGEDOORN, Ph. D 



AND 



A. C. HAGEDOORN— VORSTHEUVEL LA BRAND 



WITH 20 FIGURES 



1 4 S •»• 



THE HAGUE 

 MARTINUS NIJHOFF 



1921 



