36 QUESTIONS AND ANSWERS 



The latter are divided into five equal parts, each 

 part equaling two-tenths of i per cent. With a 

 little practice* one may read accurately to one-tenth 

 of I per cent. 



Why does the scale on the neck of the bottle show 

 the per cent of fat? 

 Because the graduated portion holds two cubic 

 centimeters and the specific gravity of melted but- 

 ter at 140° F. is .9. One c. c. weighs 0.9 of a gram 

 and 2 c. c. weigh 1.8 grams, which is 10 per cent 

 of 18 grams, the weight of milk taken. 



What can be done to make the scale easy to read? 

 Rub it over with a soft pencil, burnt cork or a 

 paste made by dissolving asphalt in turpentine. 



How may the test bottles be marked for identifica- 

 tion? 



1. A ground space may be made on the body or 

 neck of the bottle upon which numbers can be 

 placed with a lead pencil. 



2. Copper bands with stamped numbers can 

 surround the neck of the bottle. 



Describe a skim-milk test bottle. 



This has two necks, one having a larger bore. 

 Substances are introduced through the larger bore, 

 and the smaller one, which is graduated, is used to 

 collect the fat. 



When placing the bottle in a centrifuge, the large 

 neck should be turned toward the center of the 

 machine. 



