HEATING APPARATUS. 367 



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 ; 

 I, a hole in the middle of the cover, into which a plug is dropped 

 having a fluted stern 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 conve- 

 nient, that the flue-piece h may convey away the smoke ; a fire 

 is then lighted upon the grating J, 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 of the flue 

 and its flanch, which lie beyond that section and the fire door- 

 way and its flanch, which lie nearer, and also the four wheels, 

 two of which are on each side of the section. Fig. 5, a hori- 

 zontal section, from E to F, of Figs. 3 and 4. Fig. 6, a horizontal 

 section, from Gr to H, of Figs. 3 and 4, with a view of the four 

 handles situated at a higher level than the section, and of the 

 fire-bars at a lower level ; the same letters of reference signify 

 the same parts in all the four figures, a, the outer case of the 

 water- vessel ; b, the cover ; c, the space for water ; d, the fire- 

 place and flue ; e, the fire-bars, made in two pieces, to be intro- 

 duced through the fire doorway ; /, the ash-pit ; <?, the fire-door ; 

 h, pipes open at top and bottom, cemented into holes in the 

 bottom, and in the cover of the water-vessel ; these pipes are to 

 admit a current of air up through them, in order the more 

 speedily to carry the heat into the building ; k, the aperture in 



