288 Agricultural Chemistry — Sheep-Feeding and Manure. 



The actual amount of nitrogen contained in the gross in- 

 crease in live weight of an animal fed upon food containing a 

 given amount of that substance, cannot of course be experiment- 

 ally ascertained ; it is believed, however, that the estimate of 

 3 per cent., by which the last 2 columns of the Table are ar- 

 ranged, is not wide of the truth, though it is more probably too 

 high than too low, as we shall have occasion to show further on. 

 Assuming the figures as given in the Table to be correct, it is 

 seen, that by the feeding of 19 sheep for 14 weeks, during which 

 time they consumed 1662 lbs. of dry food, and 26,905 lbs. of 

 swedes, containing together 96 lbs. of nitrogen, only 15J lbs. of 

 that element are obtained in the increase of weight produced. 

 We learn too from the Table, that although the actual amount of 

 nitrogen consumed in pen 4 was only one half that in pens 2 and 

 3, yet the amount of nitrogen retained by the animal to 100 con- 

 sumed is almost identical in the three cases, thus indicating a close 

 connexion between the amount of nitrogen in the food, and that 

 of increase produced. It is possible that the actual per centages 

 given may not be correct, yet the relation of the amounts to each 

 other is probably a pretty close representation of the truth. It 

 would appear, however, that the sheep upon oil-cake, although 

 they consumed a larger amount of nitrogen in their food than those 

 in either of the other pens, yet they gave an increase not only less 

 in actual amount, but far less in proportion to the nitrogen con- 

 sumed, than those in either of the other pens. This result is 

 partly due to taking into the calculation the 2 sheep which in- 

 creased so very much less than the rest ; yet other experiments 

 seem to show, that however important to the progress of the ani- 

 mals a large amount of nitrogen in their food may be, their in- 

 crease will by no means be unconditionally in direct numerical 

 proportion to the amount of the nitrogen consumed, especially 

 when this is increased beyond a certain limit. 



With the exception of the last two columns, of which chiefly 

 we have been speaking, the figures in the preceding Table repre- 

 sent the actual experimental results obtained. For more conve- 

 nient reference, however, and for the study of the general bearing 

 of the facts as to the probable amount of food or constituents re- 

 quired to produce a given effect, they are arranged in Tables 7 

 and 8, which follow, so as to show the weekly consumption in 

 each pen by every 100 lbs. of live-weight of animal, and also the 

 amount consumed to produce 100 lbs. of increase. Before leaving 

 Table 6, however, we may remark, that of the mineral matter con- 

 sumed, there were in the 1st pen 60*8 per cent., in the 2nd 70*2 

 per cent., in the 3rd 57 * 9 per cent., and in the 4th 95 ■ 9 per cent, 

 derived from the home-produced root-crop, the remainder being 

 due to the dry, purchased or marketable food. 



