42 



Testing MUk and Its Products. 



be found to stick very tenaciously to the bottom of the 

 bottle in the subsequent cleaning with water. 



A convenient method of emptying test bottles is shown 

 in the illustration (fig. 12). After reading the fat col- 

 umn, the bottles are placed neck down, in the half-inch 

 holes of the board cover of a five-gallon stoneware jar. 

 An occasional shaking while the liquid is running from 

 the bottles will rinse off the preciptate of sulfate of 

 lime A thorough rinsing with boiling hot water is 

 generally sufficient to remove all grease and dirt, as 

 well as acid solution from the inside of the bottles, 

 The apparatus shown in fig. 13 will be found convenient 

 for this purpose. After the bottles have been rinsed a 

 second time, they may be placed in an inverted posi- 

 tion to drain, on a galvanized iron rack, as shown in 

 fig. 14, where they are kept until needed. The outside 



of the bottles should 

 occasionally be wiped 

 clean and dry. 



47. The amount of 

 unseen fat that clings 

 to test bottles used 

 for testing milk or 

 cream, is generally not sufficient to be noticed in test- 

 ing whole milk, but it plays an important part in test- 

 ing samples of separator skim milk. It may be readily 

 brought to light by making a blank test with clean 

 water in bottles used for testing ordinary milk, which 

 have been cleaned by simply draining the contents and 

 rinsing once or twice with hot water; at the conclusion 

 of the test the operator will generally find that a few 



Fig. 14. Draining rack tor test bottles. 



