allowed to pass out through a hole in the roof.

FIG. 5.—A CHIMNEY AND FIREPLACE IN AN OLD ENGLISH CASTLE.

The eleventh century brought a great improvement in the art of heating, and the improvement came from England. About the time of the Conquest (1066) a great deal of fighting was done on the roofs of English fortresses, and the smoke coming up through the hole in the center of the roof proved to be troublesome to the soldiers. So the fire was moved from the center of the floor to a spot near an outside wall, and an opening was made in the wall just above the fire, so that the smoke could pass out. Here was the origin of the chimney. Projecting from the wall above the fire was a hood, which served to direct the smoke to the opening. At first the opening for the smoke extended but a few feet from the fire, but it was soon found that the further up the wall the opening extended the better was the draft. So the chimney was made to run diagonally up the wall as far as possible. The next and last step in the development of the chimney was to make a recess in the wall as a fireplace, and to build a separate structure of masonry—the chimney—for the smoke. By the middle of the fourteenth century chimneys were usually built in this way (Fig. 5). As the fireplace and chimney cleared the house of soot and smoke, they grew in favor rapidly. By the end of the fifteenth century they were found in the homes of nearly all civilized people.

FIG. 6.—A STOVE OF THE MIDDLE AGES.

The open fireplace was always cheerful, and it was comfortable when you were close to it; but it did not heat all parts of the room equally. That part next to the fireplace might be too warm for comfort, while in another part of the room it might be freezing. About the end of the fifteenth century efforts were made to distribute heat throughout the room more evenly. These efforts led to the invention of the modern stove. We have learned that the origin of the stove is to be sought in the ancient brazier. In the middle ages the brazier in France took on a new form. Here was a fire-box (Fig. 6) with openings at the bottom for drafts of air and arrangements at the top for cooking things. This French warming-pan (réchaud) was the connecting-link between the ancient brazier and the modern stove. All it lacked of being a stove was a pipe to carry off the smoke, and this was added by a Frenchman named Savot, about two hundred years ago. We owe the invention of the chimney to England, but for the stove we are indebted to France. The Frenchman built an iron fire-box, with openings for drafts, and connected the box with the chimney by means of an iron flue or pipe. Here was a stove which could be placed in the middle of the room, or in any part of the room where it was desirable, and which would send out its heat evenly in all directions.

FIG. 7.—THE MODERN STOVE.

FIG. 8.—AN OLD-FASHIONED FIREPLACE AND OVEN.

The first stoves were, of course, clumsy and unsatisfactory; but inventors kept working at them, making them better both for cooking and for heating. By the middle of the nineteenth century the stove was practically what it is to-day (Fig. 7). Stoves proved to be so much better than fireplaces, that the latter were gradually replaced in large part by the former. Our affection, however, for a blazing fire is strong, and it is not likely that the old-fashioned fireplace (Fig. 8) will ever entirely disappear.

The French stove just described is intended to heat only one room. If a house with a dozen rooms is to be heated, a dozen stoves are necessary. About one hundred years ago there began to appear an invention by which a house of many rooms could be heated by means of one stove. This invention was the furnace. Place in the cellar a large stove, and run pipes from the stove to the different rooms of the house, and you have a furnace (Fig. 9). Doubtless we got our idea of the furnace from the Roman hypocaust, although the Roman invention had no special pipe for the smoke. The first furnaces sent out only hot air, but in recent years steam or hot water is sent out through the pipes to radiators, which are simply secondary stoves set up in convenient places and at a distance from the source of the heat, the furnace in the cellar. Furnaces were invented for the purpose of heating large buildings, but they are now used in ordinary dwellings.