MANURE. 133 



gle cow, will therefore give annually, fed on hay and 

 potatoes, 31,025 lbs. of dung, containing 

 4,400 lbs. of geine, 

 550 " of carbonate of ammonia, 



71 " of bone dust, 



37 " of plaster, 



37 " of chalk, 



24 " of common salt, 



15 " of sulphate of potash. 

 19*2. It is perfectly evident from this view, that 

 the main agricultural value depends on the ammonia 

 or nitrogen, and the geine. The lime in its forms of 

 salts, goes but little way towards this value, yet val- 

 uable, so far as they exist. It is evident from sec- 

 tion 74, that the lime in the above salts of lime, the 

 annual product of one cow, is sufficient to supply 

 the grain and straw of a crop of wheat, of twenty 

 bushels per acre, on three acres. 



193. If these, then, are the elements of plants 

 which are found in cow-dung, is it to the organic or 

 the inorganic portion, that the enriching power is 

 due ? The great value of dung as a manure, has 

 been supposed to be due to its animal matter. The 

 common idea of animal matter includes substances 

 which contain much nitrogen, but is it to the nitro- 

 gen, or to salts, that the chief value of manure is 

 12 



