HOW CROPS GROW. 



A TREATISE ON THE 



CHEMICAL COMPOSITION, STRUCTURE 

 AND LIFE OF THE PLANT, * 



FOE STUDENTS OF AGKICULTUKE. 



, WITH 

 NUMEROUS ILLUSTEATIONS AND TAJBLJSS OF ANALYSES. 



BY 



SAMUEL W. JOHNSON, M. A., 



PEOFESSOK OP THEORETICAL AND AGBIOtJLTtTBAL CHEMISTEY IN THE SHSI^ 



FIELD SCIENTIFIC SCHOOL OP TALE DlflVEKSITY ; DIRECTOR OF 



THE CONNECTICUT AGEICrLTDRAL EXPERIMENT STATION; 



MEMBER OF THE NATIONAL ACADEMY OF SCIENCES. 



SEriSED AND ENLABOED EDITIOS. 



NEW YORK; 



0KANGE JUDD COMPANY, 



1891., 



