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analyses of the products of six different plat.«. 

 containing a large number of plants. 



Dry Crop : 1000 parts. Manure used: 442 parts. 



Com. of the crops. Com. of the manure. Difference. 



Carbon, 46.4. 15.9. 30.5. 



Hydrogen, 54.6. 18.7. 35.9. 



Oxygen, 416.0. 114.0. 302.0. 



Nitrogen, 12.4. 8.8. 3.6. 



Salts, 53.0. 141.7. 88.7. 



^^ It is to be particularly remarked, that the 

 oxygen, hydrogen and carbon, contained in 

 the crop, form a total much greater than that of 

 the manures; and these results would even in- 

 duce the belief that manures have but a secon- 

 dary importance in furnishing these three bo- 

 dies, if direct experiments had not proved their 

 efficacy in this respect. Happily, the sub- 

 stances supplying these principles to plants are 

 found abundantly in nature. The leaves of 

 trees and of a great number of plants, the roots 

 and stubble of preceding crops, the straw of 

 the gramineals and all vegetable and animal 

 matters in general, contain them plenteously. 

 In a word, the air by its oxygen and carbonic 

 acid; — water by its elements and the gases 

 which it always holds in solution ; and a multi- 

 tude of other substances procurable at low 

 prices, all contribute in supplying to plants the 



