ON MILK AND MILK-TESTING 33 



Describe the Babcock test machine. 



• Various styles are found on the market made to be 

 run by hand, steam, or electrical power. They vary 

 in size from the small two- or four-bottle tester, 

 convenient to carry from place to place, to the 

 larger machines accommodating 24 or more bottles, 

 and suitable for f actory~ work. They usually con- 

 sist of an inclosing frame or covering and a hori- 

 zontal revolving disk attached to a shaft in the cen- 

 ter. Swinging pockets for holding test bottles are 

 attached to the rim of the disk in such a way that 

 they hold the bottles upright when the disk is quiet, 

 but in a horizontal position, with the opening 

 toward the center, when the disk is revolving. In 

 steam machines a turbine is attached, either to the 

 upper or lower end of the shaft. These machines 

 are very satisfactory for factory work where steam 

 power can be used, while the hand machines are 

 more suitable for testing small dairies or where a 

 few tests are made occasionally. 



How can one determine the number of revolutions 

 the disk makes for one revolution of the handle 

 in a hand machine? 

 Mark a point on the rim of the disk and turn the 



handle slowly once around, counting the number 



of times the point on the disk reaches the point at 



which it started. 



How many revolutions per minute should the disk 

 in a Babcock machine make in order to do good 

 work? 



The number of revolutions depends upon the 

 diameter of the circle in which the bottles whirl. 



