SCIENTIFIC AGRICULTURE. 105 



quantity of water prevents too rapid fermentation and pre- 

 serves the virtues of this manure to a considerable extent 



The excrements of the hog are said to be a rich manure ; but 

 they have a strong and unpleasant odor, and often impart a 

 rank taste to the crops upon which they are used: for this 

 reason it has been advised not to use them on crops, particu- 

 larly of roots, which are designed for food. They are colder 

 and less inclined to ferment than those of the cow, and should 

 be combined with other manures or made into composts. 



The excrements of sheep form a richer and more fermentable 

 manure than those of the cow : they are said to be most bene- 

 ficial on soils which contain much vegetable matter, which 

 absorbs the volatile matters which would otherwise pass off 

 during fermentation. 



The value of all animal manures depends much upon cir- 

 cumstances, viz : the food upon which the animal is fed ; the 

 age and condition of the animal ; the amount of labor he per- 

 forms; the length of time and manner in which the manure is 

 kept Since, then, their value is affected by so many condi- 

 tions, it is evident that no general conclusions can be drawn, 

 which shall not be liable to exceptions; and no set of analyses 

 can furnish tables which shall in all eases agree. The following 

 tables may be relied upon as being as nearly correct as can be 

 obtained, and sufficiently so for all practical purposes. 



Excrements of birds. These are among the most powerful 

 fertilizers. The excrement of pigeons is said to be particularly 

 valuable to flax crops, for which it is held in high esteem in 

 some parts of Europe. This, like most other manures, loses 

 much of its value by being allowed to ferment without the 

 admixture of some other matters to retain its volatile elements. 

 The principal value of this, as well as the excrements of all 

 birds, which have been analyzed and used as manures, is 

 dependent mainly on the large proportions of ammonia and 

 phosphates which they contain. The excrements of hens, 



