Do not keep one part of the body warm while another part remains cold. It is wrong to bundle the neck or wear too much clothing over any part of the body. It is also wrong to wear too little and be cold.
When you are moving about, you need less clothing than when you are sitting still. When you have worked until you are very warm, it is wrong to stop to cool off. When you stop, you ought to put on a thick coat or else go into the house. If you do not, you may be chilled and made weak so that you can easily catch cold or some other disease.
111. Heating houses.—In winter our bodies cannot make heat fast enough to keep us warm unless we put on a great deal of clothing. So we warm our houses. Our grandfathers used fireplaces, but these did not give out much heat. People now use stoves, but some use a furnace in the cellar, or heat the rooms by steam. Some use kerosene stoves, but they are not so good, for they make the air bad. A room should feel neither too warm nor too cold. It is of the right warmth when we do not notice either heat or cold.
112. Change of air.—After air has been breathed it is no longer fit for use. In an hour or two you would breathe all the air of a small room once if it were not changed. When the air is partly used, you feel dull and short of breath, and your head aches. As soon as you get out of doors, you feel better. Foul air of houses and meeting places often contains disease germs. It is necessary to change the air of all rooms often. You can do this by opening a door or window. It is a good plan to sleep with your bedroom window open, so as to get good air all night.
Air passes in and out of every crack in the windows and doors. If only one person is in a room, this may make enough change of air. If many persons are in a room, you will need to change the air in other ways. You can do this by opening a door or window. Do not let the cold air blow upon any one, for it may help to make him catch cold, if the air of the room is impure. If we lower a window from the top, warm impure air may pass out above it without making a draft.
Diagram of the natural ventilation of a room.
The arrows show the direction of the air currents.
You need fresh air at night as much as in the daytime. You need not be afraid of the night air, for it is good and pure like the day air. You ought to sleep with your window open a little. You ought to open the windows wide every morning and air your bed well. At night you ought to take off all your clothes and put on a night-dress. Then hang your clothes up to air and dry.
113. When to air a room.—When you first enter a room full of bad air it smells musty and unpleasant. But after you have been in the room a while, you get used to it. If, however, you go out of doors a minute and then come back, you will smell the bad air again. If the air smells bad, open a door or window until it is sweet again.