THE FIRELESS COOKER.—The fact that fuels are expensive and that the supply of some fuels is diminishing, makes it advisable to conserve heat. This can be done in no more satisfactory way than by means of a fireless cooker.

It has been said that future historians in summing up the great achievements of the first quarter of the twentieth century will probably name as the most important, wireless telegraphy, aviation, and fireless cookery. The fireless cooker cannot be used with all methods of cooking, but its possibilities are many.

[Illustration: Courtesy of McCray Refrigerator Co FIGURE 25.
—INSULATED WALL OF A REFRIGERATOR.]

THE PRINCIPLE OF FIRELESS COOKERY.—In Experiment 2 it was found that wood did not transmit heat rapidly, while tin did. Another familiar illustration will show the difference between wood and metal in transmitting heat. A metal door knob feels very cold on a winter day, because the metal conducts the heat away from the hand rapidly, while a wooden knob is comfortable to touch. Wood is termed a poor conductor of heat. Metals are good conductors of heat.

Paper, hay, excelsior, sawdust, cork, wool, feathers, and many other materials are poor conductors of heat. If any hot substance is surrounded by any of these poor conducting materials, the heat of that substance is retained for some time. Also, if any cold substance is surrounded by a poor conductor, the substance remains cold. In throwing a piece of carpet or newspaper over an ice cream freezer, to prevent the ice from melting, one makes use of the latter principle.

[Illustration: FIGURE 26.—FIRELESS COOKER HAVING EXCELSIOR PACKING.]

The walls of a well-built refrigerator consist of a number of layers of non-conducting materials (see Figure 25).

To understand the principle involved in "cooking without fire," try the following:

EXPERIMENT 12: RETENTION OF HEAT.—Fill 2 tin measuring cups half full of boiling water. Immediately inclose one cup of water in a paper bag or wrap paper about it so there will be considerable air space between the cup and paper. After 15 minutes, insert a thermometer into the water in each of the cups. Which is hotter? What has "kept in" the heat of the hotter water?

The fireless cooker is a device containing cooking kettles which are surrounded by some poor conductor. When food is heated thoroughly, the heat can be retained for a number of hours by placing the hot food in the fireless cooker.

[Illustration: FIGURE 27—FIRELESS COOKER WITH STONE DISKS Note the kettles of various shapes]

In the ordinary fireless cooker it is possible to cook all foods that can be cooked in water at a temperature below the boiling point of water, i. e. simmering temperature. Another type of fireless cooker has a metallic or an enamel lining and is provided with movable stone disks. Both the stones and food are heated on a range and then introduced into the cooker in such a way that the stones are under and over the kettle of food. By this arrangement, foods can be cooked at a higher temperature than in the ordinary fireless cooker (see Figures 26 and 27).

There are also electric fireless cookers (see Figure 28). Such cookers are equipped with a heating element which is placed in the bottom of the insulated box. With these it is not necessary to heat the food before placing it in the cooker. The uncooked food is put into the cooker and the current turned on. By means of a clock arrangement the current may be cut off when the desired length of time of heating has passed.

[Illustration: Courtesy of the Standard Electric Stove Co FIGURE 28.—ELECTRIC FIRELESS COOKER. Has a heating element in the bottom of the cooker.]

The principle of the fireless cooker is used on some of the modern gas and electric ranges. The walls of the ovens of these ranges are surrounded by insulating materials. When an oven is heated and has reached the desired temperature, the gas or electricity is cut off, but the baking temperature is retained for some time. The top burners of some gas ranges have a fireless cooker attachment in the form of an insulated hood. The food is first heated over the burner, then the hood is lowered over the food, and the gas is cut off. The food continues to cook, however, by the retained heat (see Figure 29).

SUGGESTIONS FOR USING A FIRELESS COOKER.—One should keep the following in mind in using the ordinary fireless cooker:

[Illustration: Courtesy of the Chambers Manufacturing Co. FIGURE 29.—GAS RANGE HAVING FIRELESS COOKER ATTACHMENT, INSULATED OVEN AND HOODS.]

1. Have the food heated thoroughly before placing in the fireless cooker. (This direction does not apply to an electrical fireless cooker such as shown in Figure 28.) If the foods are small, as cereals, 5 minutes' boiling is usually sufficient cooking on the range; if large in size, as a piece of beef, 30 minutes is required to heat it through.

2. After heating, place the covered kettle containing the food into the cooker immediately. It is well to have the cooker near the range so as to waste but little heat while getting the food into the cooker.

3. The kettle should be well filled. A small quantity of food should not be placed in a large kettle. It is possible, however, to fill the large kettle almost full of boiling water, then rest a wire rack on the rim of the kettle and place a small pan containing the food in the wire rack (see Figure 26). Or place the food in a pan with sloping sides and broad rim, such as a "pudding pan," which may be set in the large kettle so as to rest on the rim.

4. Do not open the cooker to "see how the food is getting along." If the box is opened, the food must be removed at once. The food may, however, be reheated and returned to the cooker. It is sometimes necessary to follow this plan, where food requires very long cooking.

5. The length of time a food must be left in the fireless cooker varies with the kind of food and style of cooker. In many of the homemade boxes, the water does not remain hot enough for cooking after 12 hours; in some, for not more than 8 hours. If foods require longer cooking than this, they should be removed and reheated as mentioned above. Food should never be allowed to become cool in a fireless cooker.

6. After using any type of fireless cooker, let the lid remain wide open for 2 or 3 hours. Except when in use do not close it tightly.

Every thrifty housekeeper should possess and use a fireless cooker. As has been mentioned, it saves fuel, prevents the strong odor of food permeating all parts of the house, lessens work and care in cooking, prevents burning and scorching, and provides workers and picnickers with warm lunches. A fireless cooker can be made satisfactorily at home with little expenditure of effort and money. It has been found that paper crumpled so as to afford considerable air space is a satisfactory non-conducting material for a fireless cooker. Detailed directions for making a fireless cooker are given in United States Department of Agriculture, Farmers' Bulletin 771, "Homemade Fireless Cookers and Their Use" and in several popular books.

CORN-MEAL MUSH

4 cupfuls boiling water 1 cupful corn-meal 1 teaspoonful salt

Mix the ingredients in the small pan of the fireless cooker and cook directly over the flame of a range, boiling for 5 minutes, and stirring occasionally. Cover and place in the large kettle of the fireless cooker which contains boiling water. Place in a fireless cooker for 5 to 10 hours.

NOTE.—If corn-meal mush is to be cooked over a flame in a double boiler, prepare according to the general rule for cereals and cook over boiling water for at least 3 hours.

CORN-MEAL MUSH FOR "FRYING"

2 cupfuls corn-meal 2 tablespoonfuls flour 2 teaspoonfuls salt 2 cupfuls cold water 1 quart boiling water

Mix the dry ingredients, add the cold water, and mix thoroughly. Place the boiling water in the small pan of the fireless cooker. Stir the corn-meal mixture into the boiling water and cook 10 minutes directly over the flame, stirring constantly. Cover and place in the large kettle of boiling water. Place in the fireless cooker 5 to 10 hours. Remove the pan of mush from the water and allow the mush to cool.

NOTE.—Corn-meal Mush for frying may be cooked over a flame in a double boiler according to the recipe given above. Cook it for several hours.

RICE AND TOMATOES

1/2 cupful rice 1 tablespoonful butter or substitute 1/2 teaspoonful celery salt l-1/4 cupfuls boiling water 1 cupful tomatoes 1 slice onion 1 teaspoonful salt 1/8 teaspoonful pepper

In the small pan of the fireless cooker cook (over a flame) the rice, onion, and fat, stirring constantly until they are slightly brown. Add boiling water and cook until the water is almost absorbed. Add the tomatoes and seasoning and heat the mixture until it boils. Cover and place in the large kettle of boiling water belonging to the fireless cooker. Place in the fireless cooker for 3/4 hour. This food may be served as a border around meat.

QUESTIONS

In your own way, explain the principle of "cooking without fire."

What ingredient does Corn-meal Mush for "Frying" contain that plain Corn- meal Mush does not? What is the use of this ingredient in Corn-meal Mush for "Frying"? (See Wheat Flour and Corn-meal.)

How does the method of preparing Corn-meal Mush for "Frying" differ from the usual method of cooking cereals?

How many cupfuls of corn-meal in one pound? Of rice in one pound? What is the price per pound of corn-meal and rice?