4O MODERN METHODS OF TESTING MILK 



represented in Figs. 14, 15, 16 and 17. In general 

 they all consist of a revolving disc placed in a hori- 

 zontal position, and provided with swinging pockets, 



FIG. l6 SMALL HAND-TESTER 



in which the test-bottles are placed. When at rest, 

 the pockets hang down, permitting the bottles to 

 stand upright. When the disc is in motion the pock- 

 ets swing out, carrying the bottles to a horizontal posi- 

 tion, the necks of the bottles being directed in toward 

 the center. The testers should be made to carry an even 

 number of bottles. The steam-turbine tester is the 

 best form of centrifugal for factory work. It has the 

 advantage of maintaining a uniform rate of speed 

 and, in addition, the contents of the bottles are kept 

 hot, and hot water is supplied. In some forms, in 

 which the exhaust steam is not carried away and in 



