HOW CROPS GROW. 



A TREATISE ON THE 



CHEMICAL COMPOSITION, STRUCTURE 

 AND LIFE OF THE PLANT, 



FOR STUDENTS OF AGRICULTURE. 



WITH 



NUMEROUS ILLUSTRATIONS AND TABLES OF ANALYSES 



BY 



SAMUEL W. JOHNSON, M. A., 



a 



PROFESSOR OP THEORETICAL AND AGRICULTURAL CHEMISTRY IN THE 8 HEP 



FIELD SCIENTIFIC SCHOOL OF YALE UNIVERSITY ; DIRECTOR OP 



THE CONNECTICUT AGRICULTURAL EXPERIMENT STATION; 



MEMBER OP THE NATIONAL ACADEMY OP SCIENCES. 



REVISED AND ENLARGED EDITION. 



NEW YORK: 



OBANGE JUDD COMPANY, 



1900 



