251] THE MANUFACTURE OF BUTTER 2 J 



correct price for his milk in order that he may successfully 

 compete. From the farmers' viewpoint, the justice of the 

 method must also be recognized. The farmer who* has 

 spent much time and money in developing a pure-bred dairy 

 herd has more valuable property than the farmer with the 

 " general-purpose " cows, and in order that the return on 

 this form of capital may be in all cases equal to what it 

 produces it is necessary to sell the milk on the basis of the 

 fat that it contains. It need not be said that this method 

 eliminates the evil of adding water and enforces honesty 

 among all the patrons. 



The principles upon which the Babcock tester is based 

 are chemical action and centrifugal force. Commercial sul- 

 phuric acid is added to the milk to break up thoroughly all 

 milk solids, other than the fat, which is set free by the 

 action. The fat can then be very easily separated by cen- 

 trifugal force. The mixture is put in a bottle and the 

 bottle then placed in a pocket of an apparatus by which it 

 is whirled for five minutes or more, after which the fat 

 appears in the neck of the bottle. The neck of the bottle 

 is graduated to show the percentage of fat in the milk. 

 The method is very accurate and so simple that a person 

 of ordinary intelligence can make the test. Furthermore, it 

 can be done quickly, which is a great advantage for use in 

 the creamery as well as for purposes of inspection. 



The idea of first treating the milk chemically and then 

 subjecting it to centrifugal force was tried out in Europe 

 before Dr. Babcock of this country perfected the method. 

 For instance, Dr. De Laval, of Stockholm, one of the in- 

 ventors of the separator, used a mixture of glacial acetic 

 acid and sulphuric acid, with which he treated the milk and 

 then whirled it in an apparatus which he called the lacto- 

 crite. 1 According to the account of the tests made, the 



1 New York State Dairy Commissioner's Report for 1888, pp. 242-3. 



