OREAM. 



211 



Wanklyn from different cows show a most remarkable 

 and important variation. 



The result of such a difference as this, and it is by no 

 means an uncommon occurrence, is of the highest interest 

 to dairymen selling cream to the creameries by the inch 

 or quart. For if one inch of No. 2 gives a pound of 

 butter an inch of No. 4 would give two to five ounces, 

 and an inch of Xo. 6 would give over three pounds. If 

 No. 6 gives a pound of butter per inch, No. 2 would give 

 less than six ounces. Either the patron would lose or 

 gain as his cream might be richer or poorer, and the 

 creamery would be subject to the same risk in an 

 inverse ratio. In any case there would be great loss 

 and injustice to some persons concerned. This uncer- 

 tainty is to some extent avoided by the use of what 

 is known as the '^oil test," to be explained hereafter 

 (Chapter XIX). 



jThe methods of separating the cream from the milk 

 fare three in number, viz., the deep pail system, the 

 • shallow pan system, and the centrifugal creamer. The 

 \deep pail system is derived from the method which has 

 been common in Sweden for many years, and which is 

 /there known as the Schwartz method. It is based on 

 the fact that the rapid cooling of the milk to a low tem- 

 iperature and the maintenance of this temperature causes 

 Ithe entire separation of the cream in a few hours; the 

 lower the temperature the more rapid being the sepa- 

 ration. There are several kinds of apparatus in use 

 adapted for this system which will be described more 

 (fully in a succeeding chapter. The use of water from a 



