Agricultural Chemistry — Sheep- Feeding and Manure. 285 



the mean increase of the other 4. In pen 3 the clover- chaff does 

 not give a single bad result, and owing to a comparatively large 

 gross increase in one case (which, as we shall afterwards see, was 

 an over estimate of the real progress), gives the highest mean of 

 all the pens. As has been observed already, the oat-straw chaff 

 was almost entirely refused by the sheep of pen 4, and it was 

 therefore discontinued after 4 weeks' trial. One of the animals, 

 moreover, No. 5, lost from the commencement, and it was re- 

 moved unwell from the experimental pen after the 4th week, but 

 recovered on better diet. The 4 remaining, give, as might be 

 expected, an increase very inferior to the mean of the other pens, 

 and the result can scarcely be fairly compared with them. 



Setting aside pen 4, the mean increase of the first 3 pens, taken 

 together, is believed to be a fair practical result ; and it is probable 

 that such variations upon the same food as have been noticed are 

 by no means uncommon, and although they arise chiefly from 

 variations in constitution, and cannot therefore be attributed to 

 the food consumed, yet it is probable that they will be more 

 likely to exhibit themselves under a high than under an inferior 

 diet, provided this be not deficient. 



In endeavouring to estimate the comparative feeding value of 

 the several descriptions of food with such a small number of 

 animals on each, and with such variations among them, perhaps 

 the truest indication will be obtained, by excluding those sheep 

 which appear to have been unhealthy, or at least ill adapted to 

 food, the general value of which is fully recognised. Leaving out 

 of view then the 2 sheep of pen 1 before mentioned, one of which 

 was at one period so unwell as to require removal for a time, and 

 the single sheep in pen 2 whose increase was so far below the 

 average, we shall find that the oil-cake had given the best in- 

 crease, the oats coming 2nd, and the clover- chaff 3rd. It is, 

 however, chiefly as showing the probable average increase ob- 

 tainable from a given amount of foods of known value and com- 

 mon utility, rather than as pointing out any nice distinctions 

 between them, that the results are useful. 



In the next Table are given the results of analyses of the 

 various foods, by which we shall be enabled to estimate the 

 amounts of some of the more important constituents consumed. 



The large quantities of the foods operated upon will surprise 

 those accustomed to ordinary laboratory processes. It has been 

 found, however, that the composition of most agricultural sub- 

 stances is so heterogeneous, as to require that special attention be 

 paid to the averaging and preparation of the specimens; and, that 

 it is necessary to take from the bulk with great care somewhat 

 large quantities in the first instance, more especially of roots and 

 other succulent or moist substances. These, if necessary, are 

 partially dried, to render them capable of being finely divided 



