On Agricultural Chemistry. 



257 



grain by 2240 lbs. — the production of 576 lbs. of live weight, as 

 in the cases of the oxen cited above, would give 1 290 lbs. increase 

 in grain, equal to 21 bushels of wheat. 



This method of fattening bullocks may be considered as the 

 most expensive the farmer can adopt. The whole of the food 

 employed (hay and oil-cake) may be viewed as manufactured 

 articles : it is evident, nevertheless, that artificial manures would 

 have been a dearer source of ammonia than that afforded by the 

 feeding of the animals ; but when the other constituents of the 

 several manures are taken into account, the balance will be still 

 more in favour of the fatting process. The dry matter contained 

 in the food of the ox was nearly 4000 lbs ; and of this quantity, 

 deducting the little that was converted into the substance of the 

 animal, the only remaining reduction, if the dung be properly 

 manufactured, is in the carbon respired by the animal, which, 

 under the system of agriculture here advocated, is a consideration 

 of no moment. It may appear to some agriculturists that I have 

 entered into details on this subject which are both tedious and 

 unnecessary, but I would solicit a careful consideration of them. 

 I do not at all imagine that the precise relations of ammonia to 

 increase of corn, and of nitrogen in food to nitrogen of live weight 

 obtained, are really such as have been assumed for the purposes 

 of illustrating the views advocated in this paper. My object is to 

 establish as a principle, by which practical agriculture should be 

 guided, that the amount of meat or live weight of stock produced 

 upon a farm, should bear a fixed relation to the quantity of corn 

 exported. 



If the truth of this postulate be once established, and the proper 

 proportions fixed, it will no longer be necessary to enforce upon 

 the farmer any particular rotation of crops. So long as a due re- 

 lation between his production of meat and export of corn were 

 maintained, there would be no fear of an exhaustion of the soil, 

 even if he grows no green crops whatever ; and he might safely 

 be left to make his own choice of the means he would adopt. 

 His object being the production of a certain amount of meat at 

 the lowest possible expense, he would naturally devote his ener- 

 gies to the production of large green crops, in order to limit his 

 outlay in artificial food. Knowing, too, the most profitable con- 

 ditions upon which his corn could be raised, his chief attention 

 would be paid to the economical supply of food for his stock, in 

 full confidence as to the consequences of his course. In objection 

 to any rule which may assume a necessary relation between the 

 production of meat and that of corn, it may be maintained that 

 were any cheap and inexhaustible source of ammonia discovered, 

 the production of meat, as the means of exporting corn, should be 

 materially lessened. The difficulties, however, which we may 



VOL. VIIT. s 



