REPORTS ON DIFFERENT DESCRIPTIONS OF FOOD FOR STOCK. 59 



24 hours. Another sample was used in taking the specific gravity 

 of the whole milk. This was clone at first by the lactometer, but 

 latterly, as being more correct, by the bottle. About 2U00 grains 

 were acidulated with a few drops of hydrochloric acid and heated 

 to about 170°, when the casein immediately coagulated. The whey 

 was filtered through unbleached cotton, cooled down to G0°, and 

 its specific gravity taken. After the percentage of cream was 

 read off a sample of the skimmed milk was drawn from the jars 

 by means of a siphon, and its specific gravity taken likewise. 

 The object of taking these specific densities was to ascertain the 

 relative quantities of casein and oily matter, or, in other words, 

 cheese and butter, which the milk from the different foods was 

 capable of yielding. We know that the oily matter in whole 

 milk rises to the surface as cream, because it is lighter than the 

 other ingredients — the skimmed milk. The greater the difference 

 in density, therefore, of the whole milk and the skimmed, the 

 greater the quantity of butter ; and, in like manner, because 

 casein (curd) is heavier than the other ingredients — the whey — 

 the greater the difference in density of the whole milk and the 

 whey, the greater the quantity of cheese. We think the relative- 

 quantities of butter and cheese which different milks contain may 

 be more correctly estimated by these methods, if carefully done, 

 than by means of the churn and the cheese tub. In the course 

 of some experiments made subsequently to these, we discovered 

 accidentally that the density varies to a considerable amount, 

 comparatively speaking, with the age ; and as no particular atten- 

 tion was paid to have them always taken at exactly the same 

 time, the results, although carefully and laboriously made, must 

 be thrown aside. We mention this cause of failure for those who 

 may undertake similar experiments. 10 lbs. of the whole milk 

 from each cow, morning and evening mixed, were put past for 

 two or three days in small numbered " crocks," and were there- 

 after churned. The first churnings (from milk given on February 

 15th) were done in a small common upright churn. Nos. 1 a and 

 1 b were done at the usual temperature for churning cream, which, 

 however, was found to be much too low, as No. 1 a took 2 hours and 

 40 minutes, and No. 1 & 3 hours and 10 minutes. The quantity 

 was less than it should have been, and the quality was quite 

 inferior. Nos. 2 a and 2 b were churned at 66°, which, being 

 successful, was the temperature always employed thereafter. 

 All the other churnings were done in a small double churn 

 which we got made for the purpose, by Messrs Jack and Son, 

 Maybole, price £2, 5s. One of the milks from the swedes was 

 always churned with one from the mangolds ; it was observed 

 that the latter usually took fully longer time. But the most 

 remarkable thing was the colour of the butter, which was in- 

 variably very white from the mangolds, while the butter from 



