HOW CROPS FEED. 
A TREATISE ON THE 
7 
MEW YoOrx 
AG TSOIE ay 
Cs ge ES F, as < 
ATMOSPHERE AND 
AS RELATED TO THE 
Nutrition of Agricultural Plants, 
WITH ILLUSTRATIONS. 
BY 
SAMUEL W. J OHNSON, M.A., 
PROFESSOR OF ANALYTICAL AND AGRICULTURAL CHEMISTRY IN THE SHEFFIELD 
SCIENTIFIC SCHOOL ©F YALE COLLEGE; CHEMIST TO THE CONNEC- 
TICUT STATE AGRICULTURAL SOCIETY; MEMBER OF THE 
NATIONAL ACADEMY OF SCIENCES. 
NEW YORK: 
ORANGE JUDD COMPANY, 
LSoR- 
