104 PRESERVATION OF HORSE MANURE. 



Manures containing nitrogen in large quantity are 

 so exceedingly valuable, because this gas is required 

 to form gluten, and bodies of that class, in the plant; 

 this is particularly in the seed, and sometimes also in 

 the fruit. Plants can easily obtain an abundance of car- 

 boii, oxygen, and hydrogen, from the air, the soil, and 

 manures. Not so with nitrogen. They can not get 

 it from the air: there is little of it in most soils; and 

 hence manures which contain much of it, produce 

 such a marked effect. Not that it is more necessary 

 than the other organic bodies, but more scarce j at 

 least in a form available for plants. The same rea- 

 soning applies to phosphoric acid. It is not more 

 necessary than the other inorganic ingredients; but 

 still is more valuable, because more uncommon in the 

 soil and in manures. 



In all places where manure is protected from the 

 sun, and from much washing by rain, its value is 

 greatly increased. 



a. Horse manure particularly should not be left ex- 

 posed at all: it begins to heat and to lose nitrogen 

 almost immediately, as may be perceived by the smell. 

 It should be mixed with other manures, or covered by 

 some absorbent earth, as soon as possible. Almost 

 every one who enters a stable in the morning, where 

 there there are many horses, must perceive the strong 

 smell of ammonia that fills the place. I have seen in 

 some stables, little pans containing plaster of paris or 

 sulphuric acid, for the purpose of absorbing these 

 fumes, and forming sulphate of ammonia, h. The 

 liquid which runs from barnyards and from manure 

 heaps, is shown by analysis to consist of the most fer- 

 tilizing substances; and it is calculated that where 

 this is all allowed to wash away, as is the case in 

 many instances, the manure is often reduced nearly 

 one-half in its value. I have seen yards where it was 

 al.nost worthless, owing to long exposure. 



