ges of making such an
appliance in an up-to-date manner, and so to-day we have on the market
numerous fireless cookers.

The principle of fireless cooking, though it bears the difficult name
of recaloration, is simple enough. It is merely the retention of heat
through complete insulation, just as we retain cold in the ice-box by
complete insulation. In the first case, a material which is a poor
conductor of heat is interposed between the kettle of hot food and the
surrounding atmosphere to prevent radiation or the escape of heat into
the surrounding air. In the second case, a poor conductor of heat is
placed between the ice and the warmer surrounding atmosphere to prevent
the contact of the atmosphere with the ice and the consequent
equalization of temperatures. A vacuum is an excellent non-conductor of
heat and is employed in the Thermos bottles advertised for use on
automobile trips, but a vacuum is expensive and difficult to obtain,
which accounts for the high price of Thermos bottles. The effort has
been to find some insulating agent within the means of the average
housewife. This has now been done in the metal-lined cookers.

The explanation of the cooking principle is equally simple. Ordinarily
we heat food to a certain temperature, say, the boiling point, and then
we leave it over the fire for some time, not to get hotter, that would
be impossible, but to keep it at the same degree of heat, and to do this
we must, on account of radiation into the surrounding atmosphere, keep
on supplying heat. In the fireless cooker the heat once generated is
conserved, and there is no need to add thereto.

Herein lies the economy in fuel. You have only to burn gas long enough
to bring the food to the boiling point, and the fireless cooker does the
rest. You can put dinner on to cook, and go to work, to the theatre, to
visit a friend, or read, or sew, without giving your meal any further
attention till time to serve it. This sounds like a fairy tale, but it
is absolutely true.

By the fireless cooker you save nine-tenths of the fuel, and ninety-nine
hundredths of your temper, your time, and your labor. You do not become
perspiring and cross in a hot kitchen. You do not have scorched pots and
kettles to scrape and scour and wash.

Another point in favor of fireless cooking is that it is attended by
absolutely no odors. Such vegetables as onions and cabbage can be cooked
without any one's suspecting they are in the house.

T