MILK AND ITS CARE. 17? 



In this case it will be observed that the rich- 

 ness of the milk alone is not a fair means of 

 iiKh'ini'- the value of the two cows, neither is the 

 amount of milk alone. 



2. The Babcock Method. — The method gen- 

 erally used for finding the amount of butter fat 

 in milk and its products is known as the Bab- 

 cock test, and has done more to revolutionize 

 the dairy industry than any other invention ex- 

 cept the centrifugal cream separator. This 

 method was invented by Dr. Babcock, of the 

 Wisconsin Experiment Sta<"ion, in 1890. Itisan 

 accurate, rapid method for finding the per cent, 

 of butter fat in milk, cream, skim-milk, butter- 

 milk, whey, or cheese. In this system sulphuric 

 acid is used to dissolve the solids other than fat 

 in milk, and the fat is then separated by centri- 

 fugal force, and measured on a graduated scale. 

 The apparatus includes the following (Fig. 43) : 

 test-bottles, i 7.6 centimeter pipette, acid meas- 

 ure, sulphuric acid, and a centrifugal machine 



(Fig- 44). 



(0 Test-bottles. — The test-bottles are 



made of strong glass, to withstand sudden 



changes of temperature. On the neck is a 



scale crraduated from o to 10. Each whole di- 



vision represents i per cent., and is subdivided 



into five divisions, each one reading .2 percent. 



By estimating between divisions, the reading of 



the test may be made to .1 per cent. 



