EXPERIMENT STATION BULLETINS 351 



The temperatures recorded are those at the bottom of the dish of water and about 

 the center of the bulk of milk. 



It took twenty minutes to raise the water to 70° C. and forty-five minutes to raise 

 the milk to 68° C. Had the flame been removed when the water was 70° C, the 

 milk would have been 50° C, and had the milk been allowed to stand in the water 

 with the flame removed, the milk might have gone up ten degrees more, but it is 

 very doubtful, while the water was falling ten degrees. 



If the milk were to have been properly pasteurized under the above conditions, it 

 would have taken sixty-flve minutes. 



There was a difference of four or five degrees in the water; the surface was al- 

 ways hotter than any other part. In the milk there was a vai'iation of three and 

 four degrees in different parts. 



In another experiment, the same receptacle for milk and the same water bath 

 were used. The amount of milk in this case was 370 c. c, or about 12 oz., and the 

 heat applied was more intense. The water in the water bath equaled the height 

 of the milk in the receptacle. 



Twenty-four minutes were required to raise the water to 68° C. and twenty-nine 

 to raise the milk to the same degree. There was a variation of temperature be- 

 tween the bottom and surface water of four and five degrees and in the milk of two 

 and three degrees. 



In this experiment, the temperature of the milk and water were nearer identical 

 than in the last, and less time was consumed in bringing the milk up to 68° C. 



Still another effort was made to establish the relation of the temperature of the 

 water and milk. The vessels were the same as in the last experiment and the 

 amount of milk and water identical. The flame could not be exactly controlled, 

 but it is evident that it was higher than in the previous case. 



The water was raised to 68° C. in seventeen minutes and the milk to 68° C. in 

 fifty-four minutes. When the Avater had reached 68° C, the milk was 50° C. 

 Thirty-seven minutes were required to raise the temperature of the milk to that 

 of tlie water, after the water had reached 68° C. 



