MILK AND ITS CARE. 



179 



the top of the pipette closed with the fore- 

 finger. 



(3) Acid Measure. — This holds 17.5 cubic 

 centimeters, and is usually made in the form of 

 a cylinder with a base. 



The acid used is that known as commercial 

 sulphuric acid, having a specific gravity of 1.8 1 

 to 1.83. If the 

 acid be a little 

 w^eak the fact will 

 be known by 

 white sediment 

 appearing under 

 the fat column, 

 and this may be 

 remedied by 

 usinga little more j,.,^, _^^ — hand-power babcock tester. 



acid in another this style is made especially for farm use. 



test. If the acid 



be too strong it will be indicated by the 

 column of the fat being blackened and having 

 black sediment below. This can be remedied 

 by using somewhat less acid. Acid very much 

 stronger or weaker than the standard does not 

 give satisfactory results. 



(4) Centrifugal Machine. — Many forms of 

 machines are made, varying in capacity from two 

 to forty test-bottles. The smaller (Fig. 44) 

 are made for use in small dairies, and run by 

 hand ; the larger ones are used in factory work, 



