Page:Popular Science Monthly Volume 3.djvu/207

Rh as will enable it to flow most easily into the currents prevailing in the room. These considerations led to the construction of the ventilating fireplace, which has been so extensively used in barracks. This fireplace will keep a room at a given temperature with one-third of the quantity of fuel usually required in most ordinary fireplaces, and with less than one-half the quantity required in the very best-constructed radiating fireplaces.

The open ventilating fireplace, if properly constructed, is the simplest and most effectual means of warming and ventilating a single room, because it absorbs all spare heat from the chimney beyond what is necessary to create a draught; and, while it admits warmed air into the upper part of the room in an imperceptible current, the action of the fire draws air from the lower part of the room, and thus provides for a circulation of the warmed air toward the floor of the room.

The ventilating fireplaces invented by me, and now called by my name, but which have never been the subject of a patent, were a consequence of the efforts made by the late Lord Herbert and Miss Nightingale to improve the health of the army. The death-rate of the soldiers, when this question was taken up, was found to be larger than that of many unhealthy civil populations. Soldiers are, however, a body of men picked out as the healthiest members of the nation; they should, therefore, have had an exceptionally low death-rate in peacetime. A main element in the improvement of their health lay in improving the ventilation of their barrack-rooms. But soldiers, whenever they became aware of the existence of any fresh-air currents, insisted on closing the inlets. It was also made a sine qua non by the Government that the barrack-rooms should be warmed by open fireplaces; and, moreover, the Government required that the increased amount of ventilation declared to be necessary on medical grounds should be provided without any increase in the amount of fuel allowed. By the adoption of these fireplaces, and by the introduction of simple and improved arrangements for cooking the soldiers' food, the Government were enabled to effect a saving on the fuel supplied, instead of being obliged to incur a large increased expenditure on account of the additional ventilation introduced into the barrack-rooms. The manufacturer of these fireplaces informs me that he has supplied between 9,000 and 10,000 to the military departments up to this time.

The principle of warming by means of an open fireplace, or by means of a German stove or a Gill stove, is applicable to single rooms, that is to say, each room must have its own appliance, and each room may be self-contained as far as regards its heating and ventilation.

The close stoves employed in Germany use less fuel in warming the room than any open fireplace, but they are economical because the heat generated is not removed by the frequent renewal of the air. This element of their efficiency in warming, however, makes them most unhealthy.