Xew York Agricultural Experiment Station. 137 



ing for receiving the thermometer. As the milk is spread out in 

 this thin layer it quickly takes up the heat from the steam 

 chamber surrounding it. 



The temperature of the milk is controlled by changing either 

 the valve admitting the steam or the valve regulating the milk 

 flow. A slight change in either of these valves produces a quick 

 response in the mercury column of the thermometer. Usually 

 the milk valve was set to admit about all the milk that could be 

 heated to the desired degree and the slight variations in tempera- 

 ture were controlled by changing the steam valve. 



METHOD OF WORK. 



In the manipulation of the machine at the different tempera- 

 tures the effort was always made to give it a fair chance to show 

 what could be expected of it when handled in the average cream- 

 ery at that temperature. Our ability to give it a fair trial in- 

 creased as we became familiar with the machine and its manipula- 

 tion. 



The first requisite was a method of regulating the flow of milk 

 and steam so that the temperature might be held constant. When 

 received, the machine was provided with a float intended to con- 

 trol the flow of milk automaticallv. After testins; it in a variety 

 of ways for some weeks it was condemned as too clumsy for our 

 purpose and was removed. 



As finally arranged a supply tank placed sufficiently high to 

 give a good fall was connected directly with the base of the 

 pasteurizer and the flow regulated by a hand valve. This brought 

 the milk and the steam valves near together where one man 

 could reach both and still watch the thermometer. The maxi- 

 mum variation, which rarely exceeded 10° C, usually occurred 

 at the beginning of the process before the valves were properly 

 adjusted. This having been accomplished the desired tempera- 

 ture could be maintained with very little variation. 



