25G 



On Agricultural Chemistry. 



years, in each of which 30 to 40 oxen were fatted, they may be 

 considered to afford very trustworthy information on the subject. 



Each ox received for 2*2 weeks 20 lbs. of the best clover hay, 

 and 10 lbs. of English oil- cake per day. They sold for 97. more 

 than they cost, and the average loss upon each was 4/. 1 2^. 

 Each ox received 3080 lbs. of hay = nitrogen 49 lbs. 



1470 lbs. oil-cake do. 70 lbs. 



Total nitrogen 119 lbs. 



Estimating the increase in live weight according to the increase 

 in money value at 576 lbs., and the nitrogen to amount to 3^ per 

 cent, of their weight, we have 20 lbs. of nitrogen in the meat. 



1 lb. of nitrogen gives nearly 5 lbs. of increase live weight, and 

 for each pound of nitrogen exported 5 lbs. remain for manure. 



99 lbs. of nitrogen remaining for manure are equivalent to 

 120 lbs. of ammonia. 



To supply the 120 lbs. of ammonia in Peruvian guano of 

 average quality, it would certainly require more than half a ton of 

 that manure, which at the present time would cost 5Z. The price 

 of ammonia thus obtained would be \Qd. per lb. 



In my experiments upon wheat, it required 5 lbs. of ammonia 

 to produce a bushel of corn. To obtain this amount of ammonia 

 by means of stock, there should be an increase of about 28 lbs. of 

 live weight upon the farm ; or in round numbers, to obtain 1 ton 

 of grain beyond the natural production of the soil, there ought to 

 be an increase in the weight of stock of 1000 lbs. In order to 

 bring an exhausted soil to the highest state of fertility, it will be 

 necessary to produce an amount of meat by means of imported 

 food (such as hay and oil -cake) as will be equivalent to the in- 

 crease of grain required. As the green crops increase year by 

 year, the same amount of meat will be produced, but the importa- 

 tion of artificial food will gradually decrease to the point at which 

 the Internal and external resources of the farm are so balanced as 

 to secure the largest amount of produce from the soil. 



I have not tried the comparative feeding qualities of the leaf 

 and the bulb of the turnip; but from the much higher per 

 centage of nitrogen in the former, as determined by analyses in 

 my laboratory, it may be inferred that it is much more nutritive. 

 This would be the case more particularly with the late- sown 

 turnips, when the circulation of the fluids in the leaf is still 

 active, and the plant has not had time to produce a full-sized 

 bulb. It is possible, however, that the relatively low state of 

 elaboration of the constituents of the leaf might interfere with its 

 otherwise evident applicability as a healthy food. 



According to the rule which has been assumed— namely, that 

 the production of 1000 lbs. of live weight increases the yield of 



