Food study

4. In an ordinary wood or coal stove, what becomes of the products of combustion ? Where do they go in a gas range ? Account for the difference in arrangement. 5. How is illuminating gas manufactured ? 6. What source of heat, sometimes used for cooking, is not the direct result of combustion ? DRAFTS AND THE COAL RANGE BAKED AND STUFFED POTATOES A. PREPARE STUFFED POTATOES. Wash a potato, scrubbing it well with a vegetable brush. Bake in a hot oven until soft. Cut a piece off the top and remove the contents with a fork, taking care not to break the skin. Mash the contents with a little butter, salt and pepper, and moisten with hot milk. Replace in the skin and reheat. B. Class Experiments. DRAFTS. 1. What is the effect of a draft in a stove? Try the following experiments to find out : a. Put a lamp chimney over a lighted candle, but hold it so high that it will not touch whatever the candle is standing on. Take small pieces of some light material (threads of cotton wool will do) and hold them first above the chimney, then underneath it. Is the draft passing through the chimney and in what direction, up or down? 6. Place a lighted candle in a saucer of water, and put the lamp chimney over it so that it, too, rests in the water. Why does the candle go out ? c. Fit a piece of pasteboard lengthwise into the lamp chimney. Relight the candle and replace the chimney, but set it so that the candle flame is on one side of the pasteboard partition. Why does the candle behave differently ? Test the draft. COAL STOVES 105 d. Take an empty pasteboard shoe box. Cut two holes in the cover, one at each end. Each hole is to be a little smaller than the bottom of a lamp chimney. With a drop of melted wax, stick a lighted candle to the bottom of the box so that the flame will be under one of the holes when the cover is put on. Cover, and put a lamp chimney over each hole. Test the draft by holding threads of the light material over each chimney. 2. Examine a wood or coal stove, or range. Is there a place for the air to come in as well as a place for the products of combustion to pass out? Can the size of these openings be regulated ? COAL STOVES Since air or oxygen is necessary for combustion, there must be a constant supply of air, as in a draft, for a fire to continue burning. The fire-box, then, in a stove could not be air-tight. The air coming in the door below the fire ordinarily passes out directly through the stove-pipe. The check draft in the stove-pipe may, at will, be left wide open, or turned so that it nearly closes the pipe. Besides these two means of controlling the supply of air, there is a third way. The upper door into the fire-box or a lid on top of the stove may be left open. This allows the cold air to blow across the top of the fire and cool it so that it will burn much more slowly. A fire merely built beside an oven would heat it unequally, so arrangements are made to allow the hot gases from the fire to pass entirely around the oven when it is desired to heat it. This is accomplished by shifting the oven damper. This closes the direct opening into the stovepipe and so forces the gases to pass around the oven before escaping. COAL STOVE