INTRODUCTION xxiii 



(19) Commercial nitrogen can usually be used with profit in 

 market gardening, in cotton growing, and sometimes in the pro- 

 duction of timothy hay near large cities; or, as a rule, wherevei 

 the gross returns from an acre of produce exceeds $50 or $75. 



(20) As a rule, commercial nitrogen cannot be used with profit 

 for the production of the staple grain crops, such as corn and wheat, 

 although under some conditions small applications of nitrogen 

 alone or with other elements, as in the ordinary so-called " com- 

 plete " fertilizer, may stimulate the plants sufficiently to enable 

 them to draw more heavily upon the soil, and thus return apparent 

 temporary profit in a system of ultimate land ruin. 



And other seed fell on good ground, and sprang up, and bare fruit an hundred 

 fold. JESUS. 



I applied mine heart to know, and to search, and to seek out wisdom, and the 

 reason of things. SOLOMON. 



Every man shall receive his own reward according to his own labor ; for we are 

 laborers together with God. PAUL. 



