136 MANURE. 



196. The nitrogen then, in dung, is that organic 

 element, to which must be attributed its chief en- 

 riching quality. The nitrogen is the basis, both of 

 the production ammonia, and of the formation of 

 nitrates. Hence, the quantity of nitrogen in ma- 

 nures, will form a very good element in the estimate 

 of their value. Manures will be found rich, in pro- 

 portion to their quantity of nitrogen, or their power 

 of forming nitrates. This is the great and first 

 cause of the enriching power of dung. Though 

 the action of all excrements has been referred to 

 their inorganic parts only, common experience tends 

 to the explantion which has been given of the joint 

 action of all their parts. 



197. The source of nitrogen in dung is an inter- 

 esting question. Is it ever produced from the hay ? 

 That food daily taken, does not contain as much 

 nitrogen as is contained in the evacuated solids. By 

 reference to 189, it appears that a cow consumed 

 612 lbs. of water, 87 lbs. of potatoes, 167 lbs. of 

 hay. Deducting now, the water drank, the water 

 in the hay which is about 4 percent., and the water 

 of the potatoes 75 per cent., 182 lbs. of solid food 

 were consumed in seven days, or 26 lbs. per day. 

 The daily evacuation of solids, deducting the water, 

 was 14 lbs. 



