Popular Science Monthly
��J)30
��How to Make an Efficient and In- expensive FireJess Cooker
THE materials needed are a box, or some other outside container, some good insulating material, B, a kettle for holding the food, a container for the lining of the nest in which the kettle is to be placed, and a cushion or pad of in- sulating material for the cover on top of the kettle, and a cover, G.
For the outside con- tainer a tightly built wooden box as illustra- ted is the most satis- factory. The box should have a hinged cover, and at the front a hook and staple to hold the cover down, A window fastener answers the purpose well. The size of the box should be large enough to allow for about 4 in. of pack- ing material all around the nest in which the kettle is set.
The kettles used for cooking should be dur- able and free from seams or crevices, which are hard to clean. They should have vertical sides and the covers should be as fiat as possible and provided with a deep rim fitting well down into the kettle to retain the steam. The size of the kettle should be determined by the quantity of food to be cooked. Small amounts of food cannot be cooked satisfactorily in large kettles, and it is therefore an ad- vantage to have a cooker with compart- ments of two or more different sizes. Kettles holding about 6 quarts are of convenient size for general use. Tinned iron kettles should not be used in a fire- less cooker, for, although cheap, they are apt to rust from the confined moisture. Enameled kettles are satisfactory, espe- cially if the covers are of the same material. Aluminum vessels may be purchased in shapes which make them especially well adapted for use in fireless cookers and, like enameled ware, they do not rust.
The container for the cooking vessel,
���The outside container may be any box of a convenient size
��or the lining for the nest in which it is to be put, should be cylindrical in shape and deep enough to hold the cooking kettle. It should fit as snugly as possible to the cooking vessel, but at the same time should allow the latter to be slipped in and out freely. If the cylinder is too large the air space between it and the kettle will tend to cool the food. For making this container a gal- vanized iron or other metal bucket, B, may be used or, better still, a tinsmith can make a lining of galvanized iron or zinc which can be provided with a rim, A, shown on following page, to cover the pack- ing material.
For the packing and insulating material a variety of substances may be used. Asbestos and mineral wool are doubtless the best, and have the additional ad- vantage that they do not burn. Ground cork or the packing from Malaga grapes, hay, ex- celsior, Spanish moss, wool, and crumpled pa- per may also be used satisfactorily. Of the inexpensive materials that can be ob- tained easily, crumpled paper is probably the most satisfactory, since it is clean and odorless, and, if properly packed, will hold the heat better than many of the others. To pack the container with paper, crush single sheets of newspaper in the hands and pack a layer at least 4 in. deep over the bot- tom of the outside of the container, tamping it in or pounding it with a heavy club. Stand the container for the cooking vessel, or the lining for the nest, in the center of this layer and pack in
���Section through cook- er showing insulation
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