154 manurp:. 



highly, one acre of land. This is about four sheep per year. 

 In France, it is allowed that one sheep manures about 10^ 

 feet square of land per night. 



206. Thus, the most common substances used for manure, 

 cow, horse, hog-dung, and night-soil, are reduced to geine, 

 salts, and carbonate of ammonia, or nitrogen, its equivalent. 

 It need not be said that the experience of ages has proved 

 that these varieties of manure possess very different fertiliz- 

 ing properties. These depend, not on the salts alone, whose 

 amount and quality is nearly the same in all ; nor on the 

 geine, for that is nearly the same in human and horse excre- 

 ment. Their fertilizing power, then, depends not, as has 

 been asserted, on the salts which would render their agricul- 

 cultural value equal. All experience would prove such an 

 assertion unfounded. But it is said that their relative value 

 depends on their power of producing ammonia. 



If the value of manure depended on its salts only, then its 

 ashes alone would be as effectual as the manure. Perhaps 

 no experiment determines this question more satisfactorily, 

 than that of Mr. Lawes, in England. 28 tons of yard ma- 

 nure were divided equally ; 14 tons were burned to ashes, 

 and afforded 32 cwt. The manure, 14 tons, and the 32 cwt. 

 of ashes were applied, each to one acre of land, and one acre 

 of the same land was left unmanured. The crops were as 

 follows : 



1. Manure, 1276 lbs. dressed wheat, or 22 bushels. 



2. Ashes of manure, 888 " " " 16 " 



3. No manure, 923 " « « 16 « 



Straw and chaff: 



1. 1476 lbs. 



2. 1104 " 



3. 1120 « 



