DAIRYING AND BUTTER MAKING DAIRY BUILDINGS. 799 



all purposes considered, the refrigerator can be built with most economy 

 and with better sanitary arrangement if it is constructed separate from the 

 ice house. The common ice chest in which the products to be cooled are 

 placed in the box with the ice is a very satisfactory way for handling cans 

 of milk or cream. For other products it is not so satisfactory, as it is not 

 dry enough, and if the articles are small does not afford shelf room for 

 them. • 



Use of Steam. — In a moderate-sized dairy there should be added to 

 the equipment a small steam boiler which should be in a room separate 

 from the dairy. There is always need of steam, and the additional cost 

 involved is but little compared with the benefits obtained. If steam can 

 not be provided, a small hot-water heater of some kind should be used. It 

 is essential to have plenty of boiling water for puiposes of washing and 

 scalding milk vessels and the floors and walls of the building. 



It is not within the province of this bulletin to go into details of con- 

 struction in the matter of dairv' building's. The ideas here given are gen- 

 eral in nature and involve principles that should be followed in any con- 

 struction. 



VI. The Cream Separator and Its Operation. 



Advantages of Mechanical Separation. — There are two general methods 

 in practice for creaming the milk. One is to place the milk in shallmv 

 pans or deep cans and allow the cream to rise by gravity. The other is 

 the use of the centrifugal separator. As the separator is fast displacing the 

 old method, space will be given here for a discussion of separation by 

 centrifugal force only. 



The dairyman can not afford to be without a separator. It removes 

 practically all of the butter fat from the milk, while the old method of 

 gravity skimming will leave from one-eighth to one-fourth of the butter 

 fat in the milk. The cream from the centrifugal machine is of finer 

 quality, and a much better j)roduct can be made from it. The skim milk 

 is fresh and sweet for feeding and is far superior to that from the gravity 

 system. 



There are numerous kinds of mechanical .separators on the market, 

 but they differ in detiiils of construction rather than in the principles on 

 which they work. The dairyman should thoroughly understand these 

 principles. In selecting a separator one should first determine its value 

 for good work, and then examine its mechanical construction to see if it 

 will stand long use. 



The Principles of Separation. — The force that is used to separate the 

 milk is known as centrifugal force. This force may be described as 

 the pull that is felt when a weight attached to a string is whirled about 

 the hand. It is the pull outward, and the faster the weight is whirled the 

 stronger the pull becom&s. In the old system of creaming, the separation 

 is caused by the action of gravity. The fat globules, being lighter than 

 the other portions of the milk, are forced to the top; that is, gravity acts 

 etronger or pulls harder on the heavier portions than it does on the lighter, 



