116 SCIENCE AND PRACTICE OF DAIRYING. 



well suited for this purpose. It is further important to keep the 

 covering material always dry, since it loses its properties as a bad 

 conductor of heat when it becomes wet. It may, indeed, generate a 

 certain quantity of heat through becoming fermented. It is further 

 necessary to provide every space which contains a heap of ice with 

 a chimney, so that evaporation of the water from any ice that has 

 melted may be allowed to take place, and the covering material thus 

 remain dry. Every ice-store should also be built in such a way that 

 the melted water may quickly run away. 



Ice should preferably be kept in houses with solid walls which 

 effectually keep out the air, and which are sunk considerably under- 

 ground. They should only possess one entrance towards the top 

 of the building, and it should have double doors and a drain for 

 allowing the melted water to run off. A covering is not only 

 unnecessary, but in the case of its being of an organic nature, it is 

 positively a disadvantage. In such houses the passage of air 

 currents over the layers is very much impeded. 



The less the intervening spaces between the layers of ice are, the 

 less will be the quantity of air coming into contact with the layers. 

 For this reason it is desirable that ice should be kept in regular 

 rectangular four-cornered pieces, which may rest close together, and 

 which should be cut, not by breaking, but by sawing. It is advis- 

 able to fill up the spaces between the separate pieces with sawdust. 

 Small pounded ice is not suitable for this purpose, nor is it effected 

 by pouring water in cold weather over the layers of ice. The 

 fewer the pores in the ice the better it keeps. On this account firm 

 good ice only should be used, not such as has been subjected for 

 some time to the action of a thaw. In order to obtain ice which is 

 hard and smooth on all sides, special blocks should have the snow 

 cleaned off them after every snowfall. Ice for use should never be 

 taken from the lower portion of the layer. If this be done, every 

 time the ice-stack is opened the cold heavy air which it contains is 

 expelled, and is replaced by warm air, which exerts a deleterious 

 action on the keeping of ice. If, on the other hand, the ice-stack is 

 opened from above, the cold heavy air remains in the stack, and the 

 warmer lighter air from outside cannot penetrate down into it. Ice 

 should be laid in during frost, and snow during a thaw. A snow- 

 stack collected during a thaw, and well compressed, lasts under 

 similar conditions even better than an ice-stack, because it contains 

 fewer air-spaces than the ice-stack. 



