SPECIAL ACTIOIN OF THE SULPHATE AND NITRATE. 351 



105 galloiis an acre, diluted with 500 gallons of water, and obtained, of 

 ..ay, from the 



Undressed ... ^ lb. per square yard, or 20i cwt. per acre. 



Dressed .... Ij^ lb. do. or 61i cwt. do. 



Increase ... 1 lb. do. or 41 cwt.* do. 



The increase herh is so very great that further trials with this liquor — 

 hitherto, in most country towns at least, allowed to run to waste — can- 

 not be too strongly recommended. On the dressed part, according to 

 Mr. Bishop, the Timothy grass was particularly luxuriant. 



These experiments with the gas liquor show, as I have said, that im- 

 pure carbonate of ammonia may be safely applied to the land without 

 any previous preparation. If it is wished, however, to fix it or to ren- 

 der it less volatile — which in warm and dry seasons may sometimes be 

 desirable — this may be effected by mixing it with powdered gypsum, in 

 the proportion of Tib. to each gallon of the ammoniacal liquor, or by 

 adding directly sulphuric acid, or the waste of muriatic acid of the al- 

 kali works. + 



e. Nitrate of Ammonia. — If it be correct that those substances act 

 most powerfully as manures which are capable of yielding the largest 

 quantity of nitrogen to plants, the nitrate of ammonia ought to promote 

 vegetation in a greater degree than almost any other saline substance we 

 could employ. According to the experiments of 'Sir H. Davy, (Davy's 

 Agricultural Chemistry^ Lecture VII.) however, this does not appear 

 to be the case, though Sprengel has found it more efficacious than the 

 nitrates either of potash or of soda. This question as to the relative 

 action of the nitrate of ammonia is very interesting theoretically, but it 

 directly concerns practical agriculture very little, since the high price 

 of this salt is likely to prevent its being ever employed in the ordinary 

 operations of husbandry. 



/. Special action of the different Salts of Ammonia. — The theory of 

 the action of ammonia itself upon vegetation I have in a former lecture 

 (p. 164) endeavoured to explain to you. But the special action of the 

 several saline compounds of ammonia above described will depend upon 

 the qualities of the acid with which it may be in combination. 



The sulphate will partake of the action of the sulphates of potash, 

 soda, or lime (gypsum), — in so far as it may be expected to exhibit a 

 more marked'effect upon the leguminous than upon the corn crops, and 

 upon the produce of grain than on the growth of the leaves and the 

 stem. This special action may be anticipated from the sulphuric .acid 

 it contains. And if this reasoning from analogy be correct, we should 

 expect the sulphate of ammonia to rank among the most useful of ma- 

 nures — since the one constituent (ammonia) will promote the general 

 growth of the plant, while the other will expend its influence more in 

 the filling of the ear. 



The nitrate again has been found to ac^ more upon the crops of corn 

 than upon the leguminous plants and clovers (Sprengel) — a result which 



• Prize Essays of the Highland Society, xiv., p. 359. 



t 100 gallons thus saturated with acid will convey to the soil a^xmt ICO -bs. of salphate of 

 ammonia or of sal-ammoniac. 



