These bare, while effectually preventing the emission of cinders, allow a greater space for the free radiation of heat.

The Nautilus Grate is a kind of slow-combustion dog-grate, lined with firebrick, and stands well forward into the room, but does not conform to all the principles just stated. A front view of it is given in Fig. 451. and a section in

Fig. 452. One advantage of this grate is that it can be moved out in summer, allowing the space to be filled with plants. The products of combustion rise, and, after revolving within the central tube, pass off by the nozzles, which may be at the back or at the top; the ashes fall into the special ash-pan. It is usual to tile the sides of the fireplace and the hearth. It will be observed that heat is radiated from the whole exterior of the stove, which burns ordinary fuel, and is lighted in the same manner as any ordinary stove. The makers state that a fire 12 inches wide is sufficient to heat a room of 2000 cubic feet capacity, and a fire 14 inches wide one containing 3500 cubic feet

A special type of grate for warming incoming air was designed for the War Office by Capt Douglas Galton (now Sir Douglas Galton), and has since become known as the Galton Stove. Fig. 453 is a plan of this grate; Fig. 454 an elevation of the chimney-breast, etc, showing the warm-air flue, etc.; Fig. 455 a section of the room; and Fig. 456 an enlarged section of the grate itself. Fresh air is admitted to a chamber formed at the back of the grate, where it is moderately warmed by a large heating-surface; it is then carried by a flue, adjacent to the chimney flues, to the upper part of the room, where it flows with the currents which exist in the room. With this form of ventilating grate, the inventor states1 that the temperature of a room has been found not to vary in any part to a greater extent than 1° or at most 2° F.

Fig 451   Front View of Nautilua Orate.

Fig 451 - Front View of Nautilua Orate.

Fig. 452.   Section of Nautilus Orate.

Fig. 452. - Section of Nautilus Orate.

Fig 453  Plan of the Galton Grata

Fig 453 -Plan of the Galton Grata.

Fig  454 . Elevation of Chimney breast, showing Warm air Flue. etc., from galton Orate.

Fig- 454 . Elevation of Chimney breast, showing Warm air Flue. etc., from galton Orate.

The body of the stove is of iron, but the fire is placed in a fire-clay cradle; this prevents contact between the lighted fuel and the iron which communicates heat to the incoming air.

The radiating surface obtained partly by the back of the grate and its flanges, and partly by the lower part of the smoke-flue, amounts to about 18 square feet.

Another form of the Galton Stove, which is in use at the Herbert Hospital, Shooters' Hill, Greenwich, is shown in figs. 457 and 458, the former being a plan, and the latter a section. The chimney 6 panes under the floor, and is placed in the centre of the flue a, which brings the fresh air to be warmed by the stove. By utilizing the heat of the flue in this way, more than 36 superficial feet of heating-surface are obtained for warming the fresh air, beyond that afforded by the heating- surface in the air-flues, which is from 12 to 15 feet.

Fig. 455. Section of Room showing Air flues in connection with Galton Grate.

Fig. 455.-Section of Room showing Air flues in connection with Galton Grate.

Fig. 456  Section of Galton Grate.

Fig. 456 -Section of Galton Grate.

Fig 447. plan of the Gallon Indpendent stove.

Fig 447.-plan of the Gallon Indpendent stove.

1 See Healthy Dwellings, by Sir Douglas Galton.

The fire stands in an iron cradle, fitted to the fire-clay back and sides, and a current from the air of the room is brought through the fire-clay at the back of the cradle c, - where it becomes heated, - on to the top of the fire, to assist the combustion and thus prevent smoke. The top of the stove is coved inside, to lead the smoke easily to the chimney, which passes down into the horizontal flue b under the floor. The main body of the stove is a mass of fire-clay, with flues a cast in it, up which the fresh air passes from the horizontal air-flue already mentioned, in which the smoke-flue is laid. Thus all the parts of the stove which are employed to warm the fresh air and with which the fire has direct contact, are of fire-clay. The inventor considers that the use of fire-clay is distinctly preferable to the use of iron for such a purpose, as there is less danger of burning the air.1