On Agricultural Chemist r//. 



253 



much clover grown upon an eighth as has hitherto been grown 

 upon one- fourth of the farm. We have no reason to suppos:; 

 that one grain crop possesses the power of exhausting the soil 

 more than another. Tlie tenant-farmer shoukl therefore be per- 

 mitted to grow that crop which is most suited to his soil, O.i 

 the heavy soils alternate wheat crops might be grown ; oats might 

 also be substituted for barley with advantage, whenever the soil 

 has been rendered incapable of complete pulverization, by con- 

 suming the turnips upon the land in wet weather. 



Flavlng, I trust, shown upon scientific principles that a rotation 

 of crops is indispensable in order to carry out a system of prac- 

 tical and economical agriculture, I shall n;)W endeavour to prove 

 by a few brief observations that to obtain the greatest possible 

 produce from the soil, the production of meat ought to bear a 

 definite relation to the amount of grain exported. 



The philosophical considerations to which this subject naturally 

 leads are of the highest interest ; but as it would be impossible to 

 treat of them at once clearly and at the same time as briefly as 

 our present object permits, it will be best to turn our attention to 

 some of the more practical bearings of the question. 



In feeding stock but a small proportion of the nitrogen in the 

 food is converted into the substance of the animal ; the greater 

 portion is restored to the soil as manure. The economy of the 

 production of meat as a means of obtaining manure arises from 

 the greatly increased value of the nitrogen in flesh, as com- 

 pared with that supplied in the food. Thus 28 lbs. of flesh, worth 

 145., contains 1 lb. of nitrogen — 28 lbs. of peas, beans, or oil-cake, 

 which contain about the same quantity, are not worth more than 

 25. or 35. To determine the exact proportion of the meat, or 

 rather the live weight of stock which must be produced upon any 

 farm to obtain the greatest possible produce of grain, requires a 

 long and careful series of investigation. 



With the exception of one experiment performed by Boussin- 

 gault, we have no data from which we can calculate the loss of 

 carbon and nitrogen which a farm sustains by the vital processes 

 of the animals fed upon it, but it is evident that it is most serious. 

 In Boussingault's experiments it appeared that a cow respired in 

 24 hours as much dry organic matter as was equivalent to 

 100 lbs. of turnips. This forms a strong argument in favour 

 of the modern system of fattening animals rapidly by means 

 of artificial food. When turnips are plentiful and stock is 

 dear, farmers not unfrequenlly give their turnips to any person 

 who will bring stock to consume them. And it is a common 

 practice in some places to feed a quantity of half-starved 

 cattle upon straw for the purpose of converting it into dung. It 

 should, however, be understood that the passage of the straw 



