254 



On Agricultural Chemistry, 



or turnip through the stomach of the animal, far from adding to 

 the quality of these substances as manure, abstracts a large pro- 

 portion of their valuable elements. There is no magical property 

 in the black mass called dung which did not exist in the straw. 

 Some of the elements may be rendered more rapidly available 

 by the decomposing agency of the animal ; but the actual quan- 

 titv restored to the soil must be considerably reduced. In all 

 cases, therefore, where artificial food is not employed, or when 

 the consumption of food is not attended with profit, it is better to 

 restore the superabundance of green crop more directly to the 

 soil for the after-growth of corn, whilst any residue of our corn 

 crops, if it cannot be used as litter, will, if returned to the soil in 

 its natural state, or after suffering decomposition between layers 

 of earth, supply constituents to the succeeding fallow crop. 



The increase of meat obtained by any particular food must 

 vary to a certain extent, with animals of different breeds and ages, 

 as well as with the care and attention bestowed upon them. There 

 is, however, in all cases, a relation sufficiently evident, between 

 the increase of the animal and the nitrogen in the food, to enable 

 •us to form some calculation upon the relation which should exist 

 between the production of corn and that of meat upon a well 

 cultivated farm. In illustration of this statement, in the first 

 place I may refer to some experiments made upon the farm of 

 the Earl of Radnor, regarding the feeding qualities of different 

 breeds of sheep. The results are quoted from the last number of 

 this Journal. 



In the 1st experiment, 20 sheep received 847 lbs. of hay, 

 1319 lbs. pulse, and 25,293 lbs. swedes, and the increase of live 

 weight was 400 lbs. In the 2nd experiment 1044 lbs. of hay 

 and 17,254 lbs. of turnips produced 192 lbs. of meat. Calculating 

 -the nitrogen consumed by the first lot, to be in the hay 8^ lbs., 

 in the pulse 45 lbs., in the turnips 38 lbs., and taking the per 

 centage of nitrogen in the increase of live weight at 3^, we have 

 in the first experiment— 



91j lbs. of nitrogen supplied in the food. 

 14 lbs. do. converted into flesh. 



Upon similar calculations the 2nd experiment gives — 

 ' 35 lbs. of nitrogen supplied in the food. 



7 lbs. do. converted into flesh. 



In the first experiment I lb. of nitrogen produced 4^^ lbs, in- 

 crease of flesh, and in the 2nd, 1 lb. of nitrogen produced 5 lbs. 

 increase ; not making any allowance for the probable loss by the 

 vital processes of the animals, and in the preparation of the dung, 

 we have for each pound of nitrogen exported, as much in the first 

 experiment as 6^ lbs.; and in the 2nd, 5 lbs. remaining for ma- 

 nure. 



