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account has been kept, as also of crops, expenses of la- 

 bor, etc.), embrace the entire range of those agents which 

 chemistry suggests, and those which have been brought 

 to notice through the recommendation of farmers and 

 experimenters — bones, ashes, lime, salt, the nitrates 

 of potassa and soda, sulphate of ammonia, carbonate 

 of ammonia, plaster, potashes, fish pommace, shorts, 

 muck, horn shavings, and lastly the refuse of the 

 Maine lobster factories. The methods of application 

 and the conditions under which these have been em- 

 ployed, the combinations produced, present details 

 which although extremely interesting, are too exten- 

 sive to enter upon in this essay. A definite end has 

 been kept in view, that of securing practical facts from 

 which safe general conclusions could be reached. Of 

 course, many experiments known to be empirical, have 

 been undertaken, and the results noted. For example, 

 a half acre of grass land was divided into eighteen equal 

 parts, and eighteen different substances applied : the re- 

 sults were curious, but the experiment actually proved 

 nothing, although a great difference was observable in 

 the crops of grass. More than one half of the experi- 

 ments which we find reported from year to year, are of 

 this nature. The substances affording the highest satis- 

 faction have been those which furnished in largest quan- 

 tity and at the lowest rates, the great fundamentals of 

 plant food, phosphoric acid, lime, potash, nitrogen. These 

 have been obtained from bones, ashes, potashes, fish pom- 

 mace, and nitrate of soda principally. Bones have been 

 largely dissolved in acid, and true phosphate and super- 

 phosphate of lime made upon the farm premises. Bones 

 ground and unground have been dissolved in the caustic 

 lye of ashes, also in commercial potashes, and fertilizing 



