THE IMPORTANCE OF NITROGEN. 85 



labor and his largest expenditures for fertilizing matter, are 

 made necessary for the purpose of supplying his field with 

 an adequate amount of nitrogen for the growth of good 

 crops. Does he spend labor and care in the preparation of 

 the soil ? it is that nitrogen compounds may be developed in 

 it. Does he feed his cattle with rich food purchased at 

 great cost? it is that the manure may be enriched with as 

 large a quantity as possible of this valued element. Does 

 he laboriously gather organic matter and lime, and compost 

 these with his manure, and sedulously watch over the de- 

 cay of these materials? it is that the nitrogen developed 

 may not be lost, but preserved for use to supply the never 

 satisfied needs of his crops. And thus his thoughts by day, 

 and his reflections by night ; his labors ; studies ; and ex- 

 penditures ; all center upon this one most important, but 

 otherwise inconsiderable element of vegetable matter. 



With regard to an element so difficult to be procured, it 

 is a serious fact that its consumption in the soil is compara- 

 tively large. A crop of hay takes 60 Ibs. of it from one 

 acre of the soil; a crop of clover removes 180 Ibs. ; wheat 

 carries off 45 Ibs. Hereafter this subject will be pursued 

 to its completion, here it is the purpose to consider the 

 sources from which plants can procure their supply rather 

 than the amount of it which they need. 



When we come face to face with this question we are 

 met with the fact, that the only source from which any 

 large quantity of nitrogen can be obtained is the atmosphere. 

 Nitrogen does not exist in the rocks excepting in those of 

 an organic origin as coal ; the atmosphere is the great store- 

 house of it. Organic matter contains a considerable quan- 

 tity of it, and its decay in the soil furnishes the crops with 

 a large part of their demands; but the first plants which 

 covered the soil must have procured their supply, as they 

 procured their carbon ; viz, from the atmosphere, primarily. 

 But in coming to this conclusion it by no means follows that 

 the nitrogen of the atmosphere is directly absorbed by 

 plants and made subservient to their growth ; or that it is 

 absorbed in an uncombined state through any other me- 



