EXPEKIMENTS ON CLOVER-SOILS. 161 



tainty of a good result, than such food can be applied to the laud 

 ill the shape of uilrogenous spring top-dressings." 



" Thank you Charley," sa^ia the Doctor, " thit is the moxt re- 

 mdrhtbU puper I ever liskiud to. I do not quite know what to 

 think of it. We shall have to e.vaniine it carefully." 



" The lirst three propositi<)ns \v the buuiuiary," said I, "are un- 

 questionaltly true. Proposition No. 4, is equally true, but we must 

 be careful what meaning we attach to the word 'accumulate.' Tiic 

 idea is, that clover gathers up the nitrogen in the soil. It docs not 

 increuae the absolute amount of nitrogen. It accumulates it — brings 

 it together." 



" Proposition '^In. 5, will not be disputed ; and I think we may 

 accept No. 6, al.so, though we can not be sure that allowing clover 

 to go to seed, had anytliing to ilo with the increased quantity of 

 clover-roots." 



" Proposition No. 7, may or may not l)e true. We have no 

 proof, only a ' prr)babilily ; ' and tlie same may be said in regard to 

 propositions Nos. 8, 9, and 10." 



The Deacon seemtd uneasy. He did not like these remarks. lie 

 had got the impression, while Charley was reading, that much 

 more was proved than Dr. Vadckcr claims in his Summary. 



" I thought," said he, " that on tlie part of the tield where the 

 clover was allowed to go to seed, Dr. Yoelcker found a great in- 

 crease in the amount of nitrogen." 



" That seems to be the general impression," said the Doctor, " but 

 in point of fact, we have no proof that the growth of clover, either 

 for hay or for seed, had anything to do with tlie quantity of nitro- 

 gen and phosphoric acid found in the soil. The/(/r?s given by Dr. 

 Yoelcker, are exceedingly interesting. Let us look at them:" 



" A field of 11 acres was sown to winter-wheat, and seeded down 

 in the spring, with 12 lbs. per acre of clover. The wheat yielded 

 40 bushels per acre. The next year, on the 25th of June, the 

 clover was mown for hay. We are told that ' the best pni-t of tlie 

 field yielded three tons (6,720 lbs.) of clover hay per acre; the 

 whole field averaging 2h tons (5,600 lbs.) per acre.' " 



"We are not informed how much land there was of the 'best 

 part,' but assuming that it was half the field, the poorer part 

 must have yielded only 4,480 lbs. of hay per acre, or only two- 

 thirds as much as the other. This shows that there was consider- 

 able difference in the quality or condition of the land. 



" After the field was mown for hay.it was divide'! into two parts : 

 one part was mown again for hay, August 31st, and yielded about 



