"NOW KNOW YE, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare that the nature of my said invention of a method or apparatus for heating apartments, and the manner in which the same is to be carried into effect, is shown by the following drawings and description, where Fig. 1, Plate XVI., represents a longitudinal vertical section through the middle of a metallic vessel capable of containing a considerable quantity of water, with a fire-place in the inside, surrounded with water in all parts except at the doorway and at an opening where the smoke may pass off into a common chimney. Fig. 2, a vertical section near the fire-door, at right angles to the section shown at Fig. 1; with the sections are also shown wheels and handles, which lie out of the planes of the sections. The letters of reference indicate the same parts in both figures, _a_, the vessel; _b_, the space for containing the water; _c_, the fire-place; _d_, the fire-bars, or grating; _e_, the ash-pit; _f_, an inner door, to prevent the air from entering over the fire, yet allow it to pass into the ash-pit, and thence up to the fire through the grating; _g_, an outer door, to be shut when the fire is to be extinguished; _h_, a chimney or flue, to convey the smoke into a common chimney: this flue may be removed when the water boils, and then the opening of the flue may be shut, to keep in the heat, either by a door or by a plug fitting the opening; _k_, the cover of the vessel, having a rim all round, within which iron cement is to be driven to make the vessel steam-tight; _l_, a hole in the middle of the cover, into which a plug is dropped having a fluted stem and a flat head ground steam-tight upon the cover; this plug or valve is for the purpose of allowing the escape of steam if it should be raised above boiling point, and the valve is taken out when it may be necessary to pour water into the vessel; _m_, four wheels, on which the vessel may be easily removed from one room to another; _n_, two handles, to facilitate the removal. To use this apparatus for the warming of an apartment, the vessel is nearly filled with water, and placed so near to a chimney in another room, if more convenient, that the flue-piece _h_ may convey away the smoke; a fire is then lighted upon the grating _d_, and continued till the water boils, when the flue-piece is taken away, and the flue opening stopped with the plug or door, and also the outer fire-door closed. In this state the apparatus is drawn into the apartment to be warmed, where it will continue for many hours to give off a most agreeable heat without any of that offensive odour usually experienced from stoves heated by an enclosed fire. Figs. 3, 4, 5, and 6 represent another form of my apparatus for heating churches or other large buildings. Fig. 3, a vertical section, from A to B, of Figs. 5 and 6, with a representation