CHEMICAL FERTILIZERS. 121 



of the grain and its natural proportion of stover to the acre more 

 than the natural yield of the soil, and in like proportion for other 

 quantities, use nitrogen sixty-four pounds, potash seventy-seven 

 pounds, phosphoric acid thirty-one pounds." The form in which 

 these elements may be found is stated, but is not material to this 

 point. Prof. Stockbridge assumes that fifty bushels of corn, with 

 its stover, contains the quantities of nitrogen, potash, and phos- 

 phoric acid above stated. To show that there is no mistake on this 

 point, I refer to the " Agriculture of Massachusetts," 1875-6, Fart 

 Second, p. 79, where, in an essay by Dr. Sturtevant, he gives, as an 

 average result, the quantities of nitrogen and phosphoric acid removed 

 from the soil by a crop of fifty bushels of corn and stover, within 

 a half pound of the amount assumed by Prof. Stockbridge, and the 

 potash precisely the same. And he adds, "The conclusion there- 

 fore is irresistible that if this table represents the amount of these 

 constituents removed from the soil by our crop, then this table 

 represents the actual exhaustion of the soil by the removal of our 

 crop." 



Dr. Sturtevant gives the true theory of compensation, to supply 

 what 3"0ur crop removes. Prof. Stockbridge supplies fifty and re- 

 moves a hundred, and claims that " the soil is left in better con- 

 dition than it was before being cropped by this method." * 



To illustrate : he has a measure of two gallons, which is half full 

 of a liquid. He puts into it another gallon which fills it. He 

 then pours out two gallons, and still has more than one gallon left 

 in it. The only parallel to this result is the instance of the poor 

 widow's cruse in the scriptures, and that supply was miraculous. 



I give another statement from the college report : * 



" A plot treated in the same way in 1874, produced one hundred 

 and four bushels of corn per acre. The normal capacity of the 

 land at that time, as proved by a crop on our unmanured plot, was 

 thirtj'-four bushels per acre. This manured plot was planted again 

 with corn in 1875, without manure, and its yield was sixty-four 

 bushels per acre, or thirty bushels per acre as the second result of 

 the manure applied in 1874." 



The amount of fertilizer applied is not stated. According to 

 the theory, he put on the fertilizer to produce seventy bushels 



* Thirteenth Annual Report of the Massachusetts Agricultural College, 

 page 41. 



16 



