NATURAL ICE SYSTEM 373 



between the layers prevents the ice from freezing into one solid 

 mass, and facilitates its removal. 



When the ice is stored in an insulated house, combined with 

 the refrigerator, no packing material is used except on the top of 

 the ice. Shavings are good to pile on the top of ice when the 

 ice-house has been filled. They are clean and effective in pre- 

 serving the ice. 



The cost of filling an ice-house with natural ice, obtainable 

 within a distance of about 8 miles, will vary in different localities, 

 but may be said to range between $0.60 and $1.25 per ton. The 

 creamery furnishes a man to pack it into the ice-house. 



Source of Ice. The ice for creamery use should be obtained 

 from as pure water as possible. A large running stream is always 

 better than a small polluted stream. Usually the creamery can 

 co-operate with butchers, restaurants, hotel-men, and other 

 local ice-users in building a dam in a suitable stream. The ice 

 can also as a rule be harvested cheaper by co-operation. 



Some creameries have constructed ice-ponds near the ice- 

 house. If there is a clay or impervious bottom, this works suc- 

 cessfully and economically. The pond is filled and kept filled 

 from the creamery water-supply or from a tile drain inlet. 

 Care should be taken not to use stagnant water or water in which 

 weeds and other rubbish have been allowed to accumulate. 

 The pond should be deep enough so that the water will not freeze 

 to the bottom and produce dirty ice. The pond should also be 

 filled with water to overflowing when freezing is begun; other- 

 wise slush and snow are likely to accumulate together with dust 

 from the fields and roads, producing impure ice. 



The ice is best when frozen from the top down. A hole is 

 bored in the ice and kept open during the freezing process. 

 Through this opening the pond is supplied with water as rapidly 

 as it subsides. When the water is solidly up against the bottom 

 of the ice it will show in the opening or hole in the ice. 



To construct an ice-pond on gravelly soil is useless, and to 

 pack such a pond with a sufficiently thick layer of clay to 

 prevent leakage of water is, under most conditions, imprac- 

 ticable. 



