As the immoderate size of the throats of Chimnies 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 Fire-place may be in other respects, if the opening left for the passage of the smoke is larger than is necessary for that purpose, nothing 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 employed 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 perpendicularly 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 placed. In determining this point, there are many things to be considered, and several advantages and disadvantages to be weighed and balanced.