CHAPTER III. 



THE COMPOSITION OF PLANTS SHOWING ALSO THE 

 AMOUNT OF THE DIFFERENT ELEMENTS NECES- 

 SARY TO BE ADDED AS MANURES TO PRODUCE 

 A GIVEN CROP. 



Plants of the same kind have nearly a like 

 composition ; and the relative proportions of the 

 elements that enter into the composition of 

 different plants are almost always the same in 

 each particular species. The ashes of the same 

 kind of plants, though grown on different soils, 

 closely resemble each other in chemical com- 

 position. There may be a slight diminution of 

 some particular element, from a lack of it in the 

 soil; but the variation can never be large 

 enough to materially affect the value of the 

 plant for food. 



Wheat and Corn, if produced at all, must be 

 produced of nearly a standard quality ; that is, 

 with a certain quantity of the different elements. 

 If the grains of wheat or corn could grow and 



ripen without the aid of nitrogen or ammonia, 



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