326 



AGRICULTURE FOR COMMON SCHOOLS 



Lactometers are made to use with the temperature of the 

 milk at 60° F. For each degree above this .1 of a lactometer 

 degree is added to the reading, or subtracted, if the tempera- 

 ture is below 60° F., when using the Quevenne lactometer. 

 When using the Board of Health lactometer one degree of 



76, A BABCOCK MILK TESTEK AND TESTING OUTFIT 



change is made for each three degrees of temperature. The 

 temperature should never vary much from 60° F. for good 

 results. 



2. There have been several schemes devised for determin- 

 ing the per cent, of fat in milk, but at the present time there 

 is practically but one used in this country. This is known as 

 the Babcock test, and was invented by Dr. Babcock of the 

 Wisconsin Experiment Station. In this test all the milk solids 

 except the fat are dissolved by sulphuric acid, then by means 

 of hot water and centrifugal force the fat is floated on the 



