Furnaces where air is heated in the furnace-chamber by coils of steam or by hot water, though costing more at first, require much less fuel, and do not involve the evils of warming by hot iron. The safest and pleasantest way of warming a dwelling is by steam-coils, provided there are fire-places or hot-air flues to carry off bad air. Without these, this is the most unhealthful mode of all, as there is no fresh air brought in, and what is heated is breathed over and over, till it is poisonous. The want of care in regulating the dampers of the airbox often makes a house cold, however great the furnace fire. A strong wind requires the dampers nearly closed, especially when it is on the side where the air enters from without. Every furnace should be supplied, not by cellar air, but by air taken through a shaft from a height, and so more pure. Remember that an open fire, or an opening into a hot-air flue, will ventilate properly in all seasons and all weathers. The opening should be at both the top and bottom of the room. CHAPTER V. ON STOVES AND CHIMNEYS. The simplest mode of warming a house and cooking food is by radiated heat from fires; but this is the most wasteful method, as respects time, labor, and expense. The most convenient, economical, and labor-saving mode of employing heat is by _convection_, as applied in stoves and furnaces; but for want of proper care and scientific knowledge this method has proved very destructive to health. When warming and cooking were done by open fires, houses were well supplied with pure air, as is rarely the case in rooms heated by stoves; for such is the prevailing ignorance on this subject, that as long as stoves save labor and warm the air, the great majority of people, especially among the ignorant, will use them in ways that involve debilitated constitutions and frequent disease. The most common modes of cooking, where open fires are relinquished, are by the range and the cooking-stove. The range is inferior to the stove in these respects: it is less economical, demanding much more fuel; it endangers the dress of the cook while standing near for various operations; it requires more stooping than the stove while cooking; it will not keep a fire all night, as do the best stoves; it will not burn wood and coal equally well; and lastly, if it warms the kitchen sufficiently in winter, it is too warm for summer. Some prefer it because the fumes of cooking can be carried off; but stoves properly arranged accomplish this equally well.