The Babcock Test. 55 



dred samples of milk are to be tested at a time. The 

 operator can use his time more economically in running 

 a machine of this size than one holding fifty or sixty bot- 

 tles; the work of filling or cleaning the bottles and 

 measuring the fat can be done while the tester is running 

 if a double supply of bottles is at hand. Large testers 

 require more power than smaller ones, and when sixty 

 tests are made at a time, the fat column in many bottles 

 will get cold, before the operator has time to read them, 

 unless special precautions are taken for keeping the 

 bottles warm. 



65. The tester should be securely fastened to a solid 

 foundation and set so that the revolving wheel is level. 

 The latter must be carefully balanced in order that the 

 tester may run smoothly at full speed when empty. A 

 machine that trembles and shakes when in motion is 

 neither satisfactory nor safe, and the results obtained are 

 apt to be too low. High-standing machines are more 

 apt to cause trouble in this respect than low machines, 

 and should therefore be subjected to a severe test before 

 they are accepted. 



If all the sockets are not filled with bottles when a test 

 is to be made, the bottles must be placed diametrically 

 opposite one another so that the machine will be balanced 

 when run. The bearings should be kept cleaned and 

 oiled with as much care as the bearings of a cream sepa- 

 rator. 



The cover of the machine should always be kept closed 

 while the bottles are whirled, and should not be removed 

 until the machine stops; the cover should be tight fitting 

 and may be fastened with hooks soldered on the side of 



