The Babcock Test. 69 



79. Influence of temperature on the separation of 

 fat. The intensity of the action of the sulfuric acid 

 on the milk is influenced by the temperature of either 

 liquid; the higher the temperature, the more intense 

 will be the action of the acid on the solids of the milk. 

 It may be noticed that acid from the same carboy will 

 act differently on milk in summer than in winter time, 

 if the acid and the milk are not brought to a tempera- 

 ture of about 70 before testing during both seasons. 

 The temperature of the liquids may be as low as 40 F. 

 in winter and as high as 80 F. in summer. This dif- 

 ference of forty degrees will often have considerable 

 influence on4he clearness of the fat separated, show- 

 ing white curdy substances and a light colored fat in 

 winter, or black flocculent specks, with a dark colored 

 column of fat in summer. Beth these defects can be 

 avoided, when the acid is of the proper strength, by 

 bringing the temperature of the milk and the acid to 

 about 70 F. before the milk is tested. 



The operator should be particularly cautious against 

 over-heating either milk or acid, since the heat intensi- 

 fies the action of the acid and this may become so vio- 

 lent as to force the hot liquid out of the neck of the 

 test bottle when the acid is added to the milk, thus 

 spoiling the test and possibly causing an accident. 



4. WATER TO BE USED IN THE BABCOCK TEST. 



80. Eain water, condensed steam, or soft water should 

 be used for the purpose of bringing the fat into the 

 neck of- the test bottles. The surface of the fat column 

 will then usually be' clear and distinct. The foam or 



