494 Of Chimney Fireplaces. 



tion, to the investigation of the subject I have under- 

 taken to treat. 



As the immoderate size of the throats of chimneys is 

 the great fault of their construction, it is this fault 

 which ought always to be first attended to in every 

 attempt which is made to improve them ; for however 

 perfect the construction of a fireplace may be in other 

 respects, if the opening left for the passage of the 

 smoke is larger than is necessary for that purpose, noth- 

 ing can prevent the warm air of the room from escaping 

 through it; and whenever this happens, there is not 

 only an unnecessary loss of heat, but the warm air which 

 leaves the room to go up the chimney being replaced by 

 cold air from without, the draughts of cold air, so often 

 mentioned, cannot fail to be produced in the room, 

 to the great annoyance of those who inhabit it. But 

 although both these evils may be effectually remedied 

 by reducing the throat of the chimney to a proper size, 

 yet in doing this several precautions will be necessary. 

 And first of all, the throat of the chimney should be in 

 its proper place : that is to say, in that place in which it 

 ought to be, in order that the ascent of the smoke may 

 be most facilitated ; for every means which can be em- 

 ployed for facilitating the ascent of the smoke in the 

 chimney must naturally tend to prevent the chimney 

 from smoking; now as the smoke and hot vapour which 

 rise from a fire naturally tend upwards, the proper place 

 for the throat of the chimney is evidently perpendicu- 

 larly over the fire. 



But there is another circumstance to be attended to 

 in determining the proper place for the throat of a 

 chimney, and that is to ascertain its distance from the 

 fire, or how far above the burning fuel it ought to be 



