on them--thin and straight; those are like the flat plates inside the pipe that turn just as they do. When you want the fire to burn hard you turn the handle along the pipe, and that turns the plate the same way, and the heat can get out and make a good draft. But if you are shutting up the fire you turn the handle across the pipe, and that makes the plate turn straight across, too, and stops the heat from getting out, and so the fire dies down."
"Oh, yes," said Margaret, "that's easy to understand. But what do people do who don't have coal fires? Sometimes they have wood to burn."
"But the dampers and drafts all work the same way," said her mother. "Wood is nice and clean to burn, and makes a quick, hot fire, but it has to be watched all the time or it will go out. Coal makes a steady heat, and so for most things it is better to use. Now look in and see how things are going."
Margaret raised the covers and found a bed of bright red coals. Her mother told her to put on coal at once; if sh