it is a device that, by means of air cooled by the melting of ice or in
some other manner, keeps food at a temperature near the freezing point.
All refrigerators are constructed in a similar manner, having two or
more layers of wood between which is placed an insulating material, such
as cork, asbestos, or mineral wool. The food compartments are lined with
tile, zinc, or other rust-proof material, and the ice compartment is
usually lined with rust-proof metal, so as to be water-tight and
unbreakable. Any refrigerator may be made to serve the purpose of
preserving food effectively if it is well constructed, the ice chamber
kept as full of ice as possible, and the housewife knows how to arrange
the foods in the food chambers to the best advantage.

The construction and use of refrigerators are based on the well-known
scientific fact that air expands and rises when it becomes warm. This
can be proved by testing the air near the ceiling of a room, for no
matter how warm it is near the floor it will always be warmer above. The
same thing occurs in a refrigerator. As air comes in contact with the
ice, it is cooled and falls, and the warm air is forced up. Thus the air
is kept in constant motion, or circulation.

[Illustration: Fig 12.]

47. Many refrigerators are built with the ice compartment on one side,
as in the refrigerator illustrated in Fig. 12. In such refrigerators,
there is usually a small food compartment directly under the ice
chamber, and this is the coldest place in the refrigerator. Here should
be stored the foods that need special care or that absorb odors and
flavors readily, such as milk, butter, cream, meat, etc., because at
this place the air, which circulates in the manner indicated by the
arrow, is the purest. The foods that give off odors strong enough to