There are several forms of combined open- and close-fire stoves, which stand independent of any brickwork, and are generally known as “American stoves.” These stoves are good heat givers, ornamental, and have several advantages, and can be obtained at almost any hardware stores; they do not work upon strictly hygienic principles, as they are apt to get overheated when closed, and render the air unpleasantly dry; but this can be remedied to some extent by using a vaporising pan, as will be explained later on. [Illustration: 39. Éclat Grate. Éclat Grate.] There is another form of open-fire grate that should be mentioned, viz. those that have the fire replenished by placing the fresh fuel underneath, and are known as underfed smokeless grates. This idea, which deserves high commendation, has been rendered practical, but cannot be said to be perfected yet. It originated in Dr. Arnott’s stove, which was made with the usual set of front bars fixed about 12 in. high from the hearth, and the space under the bars closed in front. The bottom of the fire, which is movable, is lowered down to the hearth and the space filled with coal: the fire is laid, and ignited on the top of this store of fuel. As the fire burns down, the bottom grating is raised by means of a lever bringing fresh fuel within the fire-basket, and this bottom is raised as often as the fire burns down; it will be seen that the gaseous products given off by the fresh fuel must pass through the incandescent fire, and so be perfectly consumed, and the space below the front bars is sufficiently large to hold fuel for one day’s consumption. “The Kensington Smoke-consuming Grate” (Brown and Green, Finsbury Pavement, London) is an underfed grate, and has received high commendation from good authorities; it has not the complication of Dr. Arnott’s, and is of good appearance, being fixed in a similar manner to any ordinary grate. “Hollands’ Patent Underfed Grate” (Hollands & Co., Stoke Newington) is a still further improvement, and, except for a little complication in construction, may be considered the best in action and results. The advantages of underfed grates are, firstly, an abatement of the smoke nuisance, full utilisation of the fuel, and more powerful radiation from the top of fire, which is always incandescent. There is commonly no provision made for the supply of air for combustion, nor to replace that which is taken from the apartment by the draught in the chimney--the cracks and fissures around doors and windows sufficing for this purpose, is the too commonly general idea; but for perfection in warming upon hygienic principles, there must be a proper supply from external sources; but this will be more fully treated under Ventilation; it will, however, be noticed that some of the ventilating stoves make provision for this in themselves; this particularly applies to Captain Galton’s principle.