EXPERIMENT STATION BULLETINS. 331 



THE BABCOCK TEST. 



Circular No. 2. » 



The Babcock test is the simplest and most practical method of deter- 

 mining the percentage of fat in whole milk, skim-milk, buttermilk, cream, 

 cheese and whey. Its economic value to the dairy industry can never 

 be estimated. Much of the progress in dairying, in recent years, is due 

 to its discovery and application. The two most important practices 

 resulting from its use are : — 



1. The purchase of milk, according to its fat content, has been made 

 practicable. 



• 2. It has enabled milk producers to detect unprofitable cows, thus 

 furnishing an intelligent guide in improving their herds. 



APPARATUS. 



The apparatus for the Babcock test consists of the following articles: — 



1. Babcock tester. 



2. 17.6 cc (cubic centimeter) pijjctte for measuring milk. 

 ;?. 17.5 cc acid measure. 



4. Sulphuric acid, specific gravity 1.82. 



5. Milk, cream and skim-milk test bottles. 

 0. A pair of calipers or dividers. 



Babcock Tester. — 



The Babcock tester consists of an encased revolving disc placed in a hori- 

 zontal position ; on the outer edge of this are swinging pockets in which 

 the test bottles are placed. When the machine is at r^st, the pockets are 

 vertical, but they assume a horizontal position when it is in motion. 

 The tester is always constructed with an even number of pockets to 

 produce a perfect balance; this is necessary for the smooth and even 

 running of the machine. Illustration 1 shows two styles of Babcock 

 testers. The one shown above a is a twenty-four bottle machine operated 

 by a steam turbine and is adapted to factory use. The one at & is a 

 twelve bottle hand machine suited to the farm dairy. The tester should 

 be securely fastened to a firm foundation and so set that the revolving 

 disc is level. There should never be any jarring or vibration of the 

 tester when running at full speed. 



The speed of the tester varies inversely with the diameter of the re- 

 volving disc, that is, the smaller the diameter, the greater must be the 

 speed and vice versa. The necessary speed for a tester is usually in- 

 dicated somewhere on the machine, denoting, with the power machine. 



