206 CHEMISTRY OF FARM PRACTICE 



meters in the graduated portion. The specific gravity of 

 milk fat is 0.90, therefore the amount required to fill the 

 graduated portion is 0.90X2 = 1.8 grams, which is 10 per 

 cent of 18 grams of milk. The milk pipette holds 17.6 

 cubic centimeters, but will deliver 17.5 cubic centimeters 

 of milk because .1 cubic centimeter will adhere to the sides 

 of the pipette. The acid cylinder is graduated to deliver 

 17.5 cubic centimeters. 



The sulphuric acid used for the Babcock test should be 



FIG. 69. Placing the milk in a test bottle. 



of a specific gravity of between 1.82 and 1.83 at 60 Fahren- 

 heit. Commercial acid, which is good enough for this test, 

 is bought at a density of 1.84. To dilute this for use in 

 the dairy, 1000 cubic centimeters of the acid should be 

 poured into 45 cubic centimeters of water, or 100 cubic centi- 

 meters of water for every ordinary 5-pint bottle of acid. 

 In reducing the specific gravity of sulphuric acid, always 

 pour the acid into water, and never pour water into the acid. 



