Proceedings of the Farmers^ Clue. 691 



• 

 quantity. But the rapidity and facility of tliis liberation of the ammo- 

 nia is liable to be modified by circumstances; as, for instance, the 

 more or less moist condition of the material, or the greater or less 

 causticity of the lime, and consequently is a poor index of the actual 

 value of the manure. The fact is, that the province of the farmer is 

 one thing, and that of the chemist another. The farmer weighs his 

 materials by the hundred weight ; the scales of the chemist are sensi- 

 tive to the five-thoiisandth part of an ounce. The farmer estimates 

 the value of a prepared manure by the bushels of gi*ain it will cause 

 to grow on a field ; the chemist, by the grains or pennyweights of 

 potash, phosphoric acid or ammonia he may find in a sample ; and 

 the two methods are so essentially different that it is unavailing for 

 the practitioners of the one to swing tlie tools or babble the language 

 of the other. The only sure path for the farmer to follow in order to 

 avoid being victimized, first, is to purchase of dealers whose commer- 

 cial standing is, in a measure at least, a guarantee of their integrity, 

 and second, to make themselves so well acquainted with the best 

 methods of using or applying the fertilizers to the soil that its virtues 

 shall not be lost by their own carelessness. If this is done, a few 

 trials will enable the farmer to approach a correct estimate of the 

 true value of his purchase. 



Fundamental Pkinciples. 



In closing this sketch it may not be out of place to recapitulate 

 some of those principles involved in the successful management and 

 use of artificial or highly concentrated manures. 



1. Tlie value of such fertilizers is to be estimated by their propor- 

 tions of ammonia and soluble phosphoric acid. The quickness of 

 their action, as compared with that of barn-yard manure, is du6 to tlie 

 rapidity with which those two substances are distributed through the 

 soil and made available for the roots of plants. 



2. In using guano, poudrette, and other ammoniated manures, 

 especial care must be taken to prevent the flying ofi" of the ammonia. 

 This is done by covering or mixing it with surface soil, by applying 

 it under such circumstances that the rain will carry it into the ground, 

 and by strictly avoiding admixture in any way with such alkaline 

 substances as potash, and lime. 



3. The value of phosphates is due not so much to the quantity of 

 phosphoric acid in them as to its solubility. This is the reason why 

 superphosphate is better than a simple phosphate. The phosphoric 



