TESTING SKIM MILK, BUTTERMILK, ETC. 97 



kept there until the contents are well darkened but not 

 charred. The test is completed in the usual manner. 

 The fat-reading is multiplied by 2. 



The method of Ross is as follows : Mix thoroughly 

 equal weights of melted ice-cream and water at 100 

 F. Weigh 9 grams of the diluted cream (containing 

 4.5 grams of ice-cream) into a cream-testing bottle, 

 preferably a 9-gram bottle with a body of the same size 

 as that of an i8-gram bottle, though a regular i8-gram 

 bottle can be used. To the contents of the bottle add 

 17.5 cc. of glacial acetic acid and agitate 2 or 3 minutes. 

 Then .add 15 cc. of sulphuric acid (sp. gr. 1.82-1.83) 

 and agitate about a minute. Complete the test in the 

 usual way. Since the amount of ice-cream used is 

 4.5 grams, the result is multiplied by 2 if a 9-gram 

 bottle is used and by 4 for an 1 8-gram bottle. 



METHOD OF TESTING UNSWEETENED CON- 

 DENSED MILK 



The most effective adaptation of the Babcock method 

 to the determination of fat in unsweetened condensed 

 milk is that worked out by Hunziker (Bull. 134, Ind. 

 Exp. Sta.). Dilute the sample of milk with an equal 

 weight of water and weigh 9 grams of this diluted 

 milk into a Babcock milk-testing bottle (graduated to 

 10 per cent.) and add one-half of a pipetteful of water 

 (about 9 cc.). Then add 17.5 cc. of sulphuric acid 

 and agitate until the curd dissolves completely and 

 whirl, as in testing milk, for 5 minutes. Then fill bottle 

 to the zero mark with hot dilute sulphuric acid, 

 made by mixing equal parts of sulphuric acid and wa- 

 ter, adding the acid to the water (p. 44). (Where 



