192 



MAJIAPEMENT OF DAIHY PLANTS 



4. Improper Method of Reading the Test. — In order to 

 comply with the Babcock system of testing the tests should 

 be read at a temperature at which the melted butter fat has 

 a specific gravity of .9. This temperature varies somewhat 

 with the composition of the butter fat, but is not far from 

 120° F., a temperature ranging from 120° F. to 140° F. is 

 usually recommended. The Iowa Experiment Station has 

 obtained satisfactory results when reading the tests at a tem- 

 perature of 130° F. For the purpose of obtaining a definite 

 temperature the test bottles should be placed in a water bath 

 at 130° F. for about fifteen minutes before the reading is taken. 



In accordance with experiments conducted by Webster 

 and Gray ' the average increase in reading a 39.8 per cent 

 cream test when the temperature is raised from 110° F. to 

 140° F. is 0.5 per cent (Table XVI). 



<Bul. No. 58, B. A. L, 1904. 



