250 BOARD OF AGRICULTURE. 



gentlemen, and to myself, than is allowed me. If it was not for 

 the important matter of cost or value in known agents, which 

 must always be balanced against the value of products, I could 

 more satisfactorily answer. 



At present, bones furnish the cheapest, iii fact the only 

 supplies of phosphoric acid, — ashes of potassa — ammoniacal 

 salts, or nitrate of soda of nitrogen. In this country, prices of 

 each of these are not yet so great as to place them beyond profit- 

 able employment ; but unless the price of farm products 

 continues to advance, in a direct ratio with the rise of the 

 agents, the time will come when their use must be relinquished. 

 Chemists are hard at work upon some problems of great 

 moment to the agricultural interests. These relate to the isola- 

 tion of those principles of fertility which are locked up in the 

 stony framework of our globe. Here we have reasonable 

 grounds for expectation and hope ; millions of pounds of 

 potassa are reposing in felspathic rocks, and it cannot be long 

 before they will be forced by chemical agents, to relinquish 

 their rich hoards of alkali. In the apatite and phosphorite 

 minerals which abound so extensively in New York and New 

 Jersey, we have abundant supplies of phosphoric acid and lime, 

 and to them must we look for future wants. 



There is not a single vegetable in the field or wood that does 

 not contain in the ash potash, in some form of combination, 

 and not a plant can be found upon our globe from which the 

 phosphates are absent ; therefore we must have full supplies of 

 these indispensable agents. 



We live in an ocean of gaseous matter made up of oxygen 

 and nitrogen ; seventy-nine pounds of the latter is contained in 

 each one hundred of the mixture. Ready at hand then is this 

 element, but unfortunately most plants arc incapable of absorb- 

 ing it in its free condition. Experiments have been made in 

 France, which give promise of a supply of the ammoniacal 

 salts, the nitrogen of which is derived from the atmosphere 

 direct. If these chemical labors prove successful, we can 

 understand through what source supplies of nitrogen may be 

 afforded. Lime and magnesia are abundant everywhere, and 

 these complete the list of important substances needed to render 

 our fields inexhaustibly fertile. 



