=6. Heating the Oven.= When baking is to be done, wait until the fire is well started; then close the oven damper. The eveness of heat in the oven depends upon the even distribution of the hot gases below and on the sides of it. This is provided for in the manufacture of the stove itself. The heat in the oven may be regulated by the intensity of the heat from the fire as well as by the damper. Whenever a cooler oven is wanted, the flame may be permitted to go directly up the chimney. Since hot air is always seeking a higher level than cold air, opening the oven door cools the oven, but it will not prevent food set on the bottom of the oven from burning on the bottom. In a closed oven, the greatest degree of heat is at the top, excepting sometimes the surface of the bottom of the oven. Many stoves require the placing of a thin grating on the bottom of the oven to prevent food from burning on the bottom. If food does not brown sufficiently on the bottom, remove the grating so that the dish comes in closer contact with the heating unit. The insulation of the oven door helps to hold heat in the oven, but the amount lost here is so small that many housekeepers prefer the convenience of the glass door, which, in turn, saves heat by doing away with the necessity of opening the oven door to watch the cooking food. Some housewives adjust the dampers for heating the oven and then never change them. They heat the kitchen in summer more than is necessary and use more fuel than they need for cooking. It has been estimated that where the careful manager of a stove uses one pound of fuel, the careless manager uses three and a half pounds. One experiment station estimated that the household coal range is used on an average of six hours a day, and, if used carefully, seven pounds of coal is consumed. Careless management, then, makes the waste of coal quite an item in the course of a year, as it is not unusual for the careless manager to use twenty-four pounds of coal per six-hour day. There is always some soot formed, even in the best-managed stoves, and the flame often carries ashes with it. These in time fill the narrow space about the oven and cut off or check the passage of the hot gases about the oven. When this happens and the oven damper is closed, the stove will smoke and not bake well. No stove should be allowed to get in this condition. The housewife can watch the accumulation of ashes in the stove and remove them before they become one-fourth inch thick. If this is not done, the oven will not heat well and some parts may be considerably cooler than others. =7. Ashes.= Ashes allowed to accumulate in the fire box will cause the lining of the stove to burn out. Ashes will also interfere with the heating of the rest of the stove. To lengthen the life of a stove, keep the ash pan empty. If a full pan of ashes becomes hot, it will keep the grate of the stove so hot that it will warp and burn out, and sometimes cause the oven to warp.