130 Agricultural Experiment Station, Ithaca, N. Y. 



of which it is supposed that the cream afterward more reudily 

 separates from the milk by gravity process. 



The apparatus and treatment is comparatively simple. The 

 machine itself consists simply of a cylindrical chamber, capable 

 of being closed air-tight. An air-pump it attached to one side 

 connected with the chamber by means of suitable valves and 

 fittings, so that the air within the chamber can be compressed 1o 

 any desired degree. The method of operation is simply to fill 

 the chamber nearly full of milk, to which twenty per cent of 

 water has been added, close the opening and apply as quickly 

 as possible, an air pressure of thirty pounds per square inch. The 

 milk is allowed to remain under this pressure for two minutes 

 when it is drawn off and set in any ordinary v-^essel. It is (claimed 

 by the manufacturers that the temperature of the milk at the 

 time of applying the pressure, the temperature of the water 

 added and the temperature of the air in which the millc is after- 

 wards set, are all immaterial, and that by means of this process, 

 the cream will all rise inside of twelve hours as <'ompletely as 

 with any of the ordinary gravity systems of setting, as may be 

 seen from the following extracts from their circular: 



" The best and quickest results will be secured when the milk 

 to be treated is rich in cream, from a new milch cow, and treated 

 while the milk is warm, immediately after the milking. In such 

 a case the cream will probably be up in one hour. 



"The poorest result will be found when the cow has been Icmg 

 in milk, when the milk is poor in cream and has stood for some 

 time and become chilled. In such cases two hours may be 

 required to raise the cream. 



"If the milk is allowed to stand in the raising vat about seven 

 hours, tho fat will rise to within two-fifths of one per cent, and 

 if allowed to stand twenty-four hours, the fat will practically all 

 rise. Much closer results will be obtained right along in practice 

 than by any other known system." 



The machine arrived at the station on March fifteenth and a . 

 member of the company set it up and gave instructions in regard 

 to its workings. From that time until the first of April thirteen 

 tests were made with it, on as many different days. Care was 

 taken to follow the directions of the company closely, particularly 



