8 



Testing Milk and Its Products. 



with a mixture of hydrochloric and sulfuric acids. This test is 

 now but rarely met with. 



13. In the De Laval butyrometer (fig. 2) the same acid is 

 used as in the Babcock test, but the tubes employed and the 

 manipulations of the method differ materially from this test; a 

 smaller sample of milk is taken (only 2 cc.) and a correspond- 



FIG. 2. De Laval's butyrometer. 



ingly small quantity of acid used. Where a large number of 

 milk samples are tested every day, as is the case, for instance, 

 in European milk control stations, the butyrometer may be 

 preferable to the Babcock test; but it requires more skill of the 

 operator and does not work satisfactorily in case of sour, lop- 

 pered, or partially churned milk. 



14. Fjord's centrifugal cream tester 1 (fig. 3) is exten- 

 sively used in Denmark and is mentioned in this connection as it 

 furnishes, as a rule, a reliable method for comparing the qual- 

 ity of different lots of milk. The method was published in 1878, 

 by the late N. J. Fjord, director of the state experiment station 

 in Copenhagen, through whose exertions and on whose authority 

 it was introduced into Danish creameries in the middle of the 



1 State Danish experiment station, Copenhagen, sixth and ninth 

 reports, 1885-7. 



