Two views of the Helios fireplace are shown in Fig. 468. When the Helios

Stove is used. with a hopper, it consists of the fire-box a, which is lined with fire-bricks, the hopper B, and the pipe-system c. Under the grate R is arranged the ash-pan s and the regulating door E. The grate is fed by opening the filling door, and removing the cover in the filling neck p. In the Helios Grate without hopper, the hopper b, the pipe-system c, and the filling neck f are abandoned. The front of the combustion-chamber above the grate is covered by a hinged mica window, which allows the fire to be seen, and possesses the notable advantage of preventing soot, smoke, or burning coals from falling into the room. The whole apparatus is firmly screwed together, and stands on small wheels P, so that it is not a fixture. The heat is diffused partly by radiation and partly by warmed air. The fire heats by radiation through the mica window, and the pipe-system warms the air, which enters cold at the gratings at the bottom of the front, and is returned to the room in a heated condition througli the top perforations at the front. The perforations and mica windows are clearly shown in Fig. 469.

Internal Elevation. Fig. 468.   The  Helios  Smoke consuming Store.

Internal Elevation. Fig. 468. - The "Helios" Smoke-consuming Store.

By pushing the regulating door as far to the right as possible, the maximum combuation is obtained, while, by moving the door more or less to the left, combustion can he regulated so as to yield the exact degree of boat required If the regulating door is quite closed, the fire merely smoulders,and, according to the maker's catalogue, burns in that condition about 7 oz. of coal per hour. Economy of fuel is guaranteed by a large area of heat-ing-surface, and per-fect control of combustion ; and consumption of smoke is attained by injection of pre heated air on the -moke arising from the fuel. Perfect consumption of smoke is, of course, most important from a hygienic point of view. In grates with hoppers, one charge, it is said, will last from four to twelve hours, according to the heat required. The fire will smoulder all night without attention. To revive it in the morning, it is only necessary to open the regulating door. The replenishing does not affect the burning fuel, so that the fire can be kept alight as long as required. Grates without hoppers hold fuel for 1 to 4 hours, according to tin-heat required. Cleaning is necessary once a year. When the heating-chamber is to be cleaned, the grate should first be wheeled out.

In order to moisten the air, a vessel, which must be daily filled with water. is placed inside the chimney breast. Either the air in the room itself may be pissed through the stove, or cold external air may be introduced, warmed, and sent out. Besides this, by an arrangement of suitable flues the warmed air produced in one room may be caused to heat one or two rooms directly over the first. The system then becomes one of heating by warmed air.

Fig. 469.   Front of the Helios  Smoke cousmlng stove.

Fig. 469. - Front of the Helios" Smoke-cousmlng stove.

These grates, with or without fronts, can be easily inserted into existing mantel-pieces; they are not fixtures. The body of the apparatus surrounding the grate is divided into three parts by fire-bricks; the fire-grate itself forms the middle division. Above this there is an air-channel conducting heated air to the flame, in order to bring about smokeless combustion; above the air-channel there is a register, for the purpose of either allowing a direct draught into the chimney, as in an ordinary grate, or to send the products of combustion through the Hues at each side of the grate. These flues can easily be cleaned by removing the cleaning cover-, which can also be used as ventilators. In front of the grates there are two sliding mica doors, or one mica door on hinges. The grates are fitted with fronts entirely of cast-iron, or with tile panels, behind which the mica doors slide when opened sideways.

The process of warming ran take place in three ways:

(1) If the mica doors and the register at the back are closed, the fire burns with a nice lambent flame according to the position of the lower sliding door, and the grate yields the greatest amount of heat.

(2) If the mica doors are closed, but the register at the back is left open, the grate still burns as described above, but as there is a direct draught into the chimney, only a small quantity of heat is given off into the room.

(3) If the mica doors are open as well as the register, the fire burns as it does in any ordinary grate, and gives hardly any heat into the room, but simply assists the ventilation.

Ventilation can be obtained by opening the valve in the cleaning covers at the bottom of the side flues; the air from the room will at once be drawn into these flues, giving ample ventilation for several persons. The draught for the fire will be slightly reduced thereby.

The "Hestia" Stove, also invented by Mr. Heim, is a true stove, standing away from the wall of the room, and is shown in Fig. 470. It stands on a plain or ornamental pedestal a, and consists of the regulating neck B, with regulating door N, movable grate D, fixed grate K, guard-ring v, one or two middle rings f, filling neck G, with smoke-nozzle and smoke-pipe M. The whole is held together and connected with the pedestal by two iron rods J. This cast-iron heating-cylinder is surrounded by an inner sheet-iron easing R, and an outer one 8, resting on the pedestal The upper part contains the- Mat filling-door o, with frame p, and the top is surrounded by a cast-iron border K, carrying a perforated cover L. The smoke-pipe M is connected with the Hue by ordinary smoke-pipes. In the regulating neck is the ash-pan c. The poker serves the double purpose of raking out the fire and lifting oft* the filling cover H. In many cases where iron stoves are need for heating purposes the dryness of the air is a source of complaint; in order to prevent this, the "Hestia" stove has a water reservoir suspended between the inner and outer easing, but free from both, so that the water may become very hot but cannot be made to boil. The reservoir is supplied by a tube opening upwards, projecting from the side of the casing, so that it can be easily filled without removing the cover of the casing. All the fuel is lighted from the top, and combustion proceeds downward, So that smoke and gases must pass through the fire, and are thus consumed before reaching the chimney. As the fire is drawn downward it goes out on the top. so that, in stoves with the several middle rings, black coke is visible on the top, sinking gradually down during the combustion. A further proof of the complete utilization of the fuel, is the fact of the smoke-pipe being almost cold.

Fig. 470   View and section of the  Hestia  stove.

Fig. 470 - View and section of the "Hestia" stove.