BY MIXED MANURES. 287 



which it is capable of yielding is nearly double that of cow 

 dung : 100 lbs. of fresh manure would yield about 3.24 lbs. 

 of carbonate of ammonia and about .96 of phosphates. 



3. Sheep dung is similar to horse dung, but contains a 

 larger quantity of vegetable matter in a soluble state. It is 

 also richer in salts ; and the fact that it tends, like the dung 

 of fowls, to putresence, shows that the quantity of nitrogen 

 which it is capable of yielding, is greater than either of the 

 preceding substances. 



4. Hog manure. Hog manure is the most valuable of ma- 

 nures. It contains still larger quantities of soluble matter, 

 and is capable of yielding a large quantity of nitrogen in the 

 form of ammonia. We have not seen any analysis of hog 

 dung, but from its known effects it ranks next in value to 



5. Night soil, which has always been celebrated as the 

 most valuable substance used for manure. The reason for 

 its powerful effects may be learned from its composition : 

 100 parts of pure night soil contain 



Water 75.3 j Pliosph. of lime and magnesia .4 



Animal and veg. matters 23.5 



Carb., mur., & sulph. of soda .8 100.0 



It will be seen that the quantity of nitrogen, which night soil 

 is capable of yielding, is about 3J per cent. The quantity of 

 carbonate of ammonia, which may be formed by the nitrogen, 

 is about 15 lbs. in 100 of night soil ; hence, if its value is es- 

 timated by the ammonia which it is capable of forming, it is 

 more than seven times that of cow dung. Experiments show, 

 that if land without manure yields 3 for 1 sown, then by the 

 addition of cow dung, it will yield 7 to 1 ; of horse dung, 10 

 to 1 ; and night soil, 14 to 1. 



The substances, now considered are generally formed to- 

 gether, and mingled in the cattle yard and hog stye. They 

 constitute the great sources of fertility to the farm ; and be- 

 fore describing the other substances, which come under this 



