TESTING MILK AND CREAM. 31 



or frothy fat colum, this can be remedied by allow- 

 ing the sample to cool, when through testing, until 

 the butter fat hardens. Then reheat, whirl for two 

 or three minutes and read at once. This will, as a 

 rule, produce a very clear reading. Since hard 

 water has a tendency to favor foam on the top of 

 the fat colum, soft water should be used; if this 

 eannat be had use condensed steam, or boil ordinary 

 water. 



33, The temperature during the first whirling may 

 be as high as 200° F. and yet not necessarily inter- 

 fere with the correct result of the test, but if this 

 temperature were employed during the two last 

 whirlings, and the bottles read immediately after 

 the testing were completed, the reading would in- 

 variably be too high, and air bubbles might appear 

 in the fat column. Therefore, the temperature dur- 

 ing the two last whirlings ought not exceed 140° P. 



THE READING OF MILK AND CREAM TESTS. 



34. Reading milk tests. According to Farrington, 

 milk tests should be read from the extreme bottom 

 line of the fat column to the extreme top of the 

 meniscus (see Fig. I, Book II). The reading from 

 A to D represents the true fat content of the milk 

 tested. C to D is the space the meniscus takes up, 

 which may be termed the per cent of meniscus. This 

 space usually represents .2 per cent on the reading 

 of the test, but not .2 per cent of the reading. Bab- 

 cock found that aboiit .2 per cent fat adheres to the 

 inside of the test bottle and does not find its way 

 into the neck of the bottle with the other fat. The 



