82 Testing Milk and Its Products. 



rate for this purpose; a small scale of this kind is also con- 

 venient and helpful in testing cheese, butter and con- 

 densed milk, in determining the strength of sulfuric 

 acid, and the accuracy of test bottles and pipettes (q. v. ). 

 In testing cream by weight, the test bottle is first 

 weighed empty, and again when 5 to 10 cc. of cream 

 have been measured into it; the difference between the 

 two weights gives the weight of cream taken for the test. 

 If the cream contains less than 30 per cent, of fat, the 

 regular milk test bottle can be used for testing the 

 cream, if not much more than 5 grams are weighed out; 

 if more cream is taken, or if this is richer than 30 per 

 cent., it is advisable to use the cream bottle. 



FIG. 33. Scale used for weigh- FIG. 34. Beebe and Spill- 



ing cream, chee?e, etc., in the man cream weighing scale 



Babcock test. 



The operator should be careful in weighing the cream 

 not to spill it on the outside of the test bottle. Suffi- 

 cient water is added to the bottle to make the total 

 volume about 15 cc. The usual quantity of acid (17.5 cc. ) 

 is then added, and the test completed in the ordinary 

 manner. The reading of the amount of fat in the neck 

 of the test bottle in this case does not show the correct 

 per cent, of fat in the cream, because less than 18 grams 

 were weighed out. The per cent, of fat in the cream 

 tested is obtained by multiplying the reading by 18, 



