The Babcock Test. 



35 



40. Adding water. Hot water is now added by means 

 of a pipette or some special device (10 in fig. 58), 1 until 

 the bottles are filled to near the scale on the neck (80). 

 The bottles are whirled again at full speed for one min- 

 ute, and hot water added a second time, until the lower 

 part of the column of fat comes within the scale on the 

 neck of the test bottle, preferably to the 1 or 2 per 

 cent, mark, so as to allow for the sinking of the column 

 of fat, due to the gradual cooling of the contents of the 

 bottle. By dropping the water directly on the fat in 

 the second filling, the column of fat will be washed free 

 from light flocculent matter, which might otherwise be 

 entangled therein and render the 

 reading uncertain or too high. A 

 final whirling for one or two min- 

 utes completes the separation of 

 the fat. 



41. Measuring the fat. The 

 amount of fat in the neck of the 

 bottle is measured by the scale or 

 graduations on the neck. Each 

 division of the scale represents 

 two-tenths of one per cent, of fat, 

 and the space filled by the fat 

 shows the per cent, of butter fat 

 contained in the sample tested. 



The fat is measured from the 

 lower line of separation between 

 the fat and the water, to the top of the fat column, at 

 the point &, shown in the figure, the reading being thus 

 taken from a to b, and not to c or to d. Comparative 



-6 





FIG. 10. Measuring the 

 column of fat in a 

 Bnbcock test bottle. 



1 See under 204. 



