66 Defcrlptlon of a new Furnace. 



to make room for frefii quantities to fall into the, furnace from 

 the hopper or mouth-piece. By this arrangement the fuel 

 is brought into a ftate of ignition before itreachi.-s the further 

 .fide pf~the bottom grate, where it is flopped by the rifing 

 breaft, Z*, of the brick-work, fo that any fmoke liberated from 

 the raw coals in the mouth-piece muft pafs over thele burn- 

 ing coals before it can reach the flue FFF. But this, though 

 it would caufe a large quantity of the fmoke to be burnt, 

 would not complctelv prevent the efcape and afcent of fmoke 

 lip the chinmey ; tor it is not mcrelv ncceffarv that the fmoke 

 •fliould be expofed to a heat fuflicient to ignite it before it 

 efcapes : imlefs, at the fame time, a quantity of frefli air, able 

 to furnifh a fufriciency of oxvgen for the combuflion of the 

 fmoke, can be brought into ccmtaft with it, it will fiill efcaj^e 

 in an undecompofcd fiate. The judicious admiflion of frefh 

 air, in fuch a manner that it can reach the fmoke, without 

 previouflv pafling through the fire, and parting with its oxy- 

 gen in its paflage, and in luch quantity as not to cool the 

 bottom of the boiler, but merely to caufe the fmoke to burn, 

 conditutes the chief merit of this invention ; and to us it 

 appears that it will fully anfwer the propofed end. Below the 

 upper fide of the mouth-piece or hopper, and at about the 

 diftance of 3-4ths of an inch from it, (this fpace being a little 

 more or lei's, according to the fize of the furnace,) is introduced 

 a cafl iron plale an. This plate is above the fuel, and the 

 fpace between it and the top of the hopper is open for the 

 admiflion of a thin Itream of air, which, rufliing down the 

 opening, conies firft in contail with that part of the fire 

 which is giving oil" the grcatefl: part of the fmoke, viz. the 

 fuel that has been latt introduced, mixes with it before it 

 palTes over the fuel in the interior, which is in a high flate 

 of combuftion, and enables it to inflame fo completely, that 

 not a particle of fmoke ever efcapes undecompofcd. 



The quantity of air thus admitted to pafs over the upper 

 furfacc of the tire, is rcfrulaled by a very fimple contrivance : 

 The plate an relts at each end on a ftud, or pin, projcfting 

 from the checks of the mouth-piece A, or is furnifhed at 

 each end with a pivot which works in the cheeks; the laid 

 pins or pivots being placed about mid-way between the out- 

 lide and infide of the mouth-piece or hopper, fo that, bv 

 clevatinoordeprcning the edge a of the plate, the opening at 

 n is enlarged or dimiuiiiieil. When that degree of opening 

 which produces the bell effects is obtained, which is eafily 

 known, the plate an is kept in its place by means of a piece 

 of iron iutrocuced above it, and anfvvering the purpofe of a 

 wedge. 



Under 



