applicable to Chimnies destined for burning Wood, or Turf, as well as those constructed for burning Coals.

The plague of a smoking Chimney is proverbial; but there are many other very great defects in open Fire-places, as they are now commonly constructed in this country, and indeed throughout Europe, which, being less obvious, are seldom attended to; and there are some of them very fatal in their consequences to health; and, I am persuaded, cost the lives of thousands every year in this island.

Those cold and chilling draughts of air on one side of the body, while the other side is scorched by a Chimney Fire, which every one who reads this must often have felt, cannot but be highly detrimental to health; and in weak and delicate constitutions must often produce the most fatal effects. -- I have not a doubt in my own mind that thousands die in this country every year of consumptions occasioned solely by this cause. -- By a cause which might be so easily removed! -- by a cause whose removal would tend to promote comfort and convenience in so many ways.

Strongly impressed as my mind is with the importance of this subject, it is not possible for me to remain silent. -- The subject is too nearly connected with many of the most essential enjoyments of life not to be highly interesting to all those who feel pleasure in promoting, or in contemplating the comfort and happiness of mankind. -- And without suffering myself to be deterred, either by the fear of being thought to give the subject a degree of importance to which it is not entitled, or by the apprehension of being tiresome to my readers by the prolixity of my descriptions, -- I shall proceed to investigate the subject in all its parts and details with the utmost care and attention. -- And first with regard to smoking Chimnies:

There are various causes by which Chimnies may be prevented from carrying smoke; but there are none that may not easily be discovered and completely removed. -- This will doubtless be considered as a bold assertion; but I trust I shall be able to make it appear in a manner perfectly satisfactory to my readers that I have not ventured to give this opinion but upon good and sufficient grounds.

Those who will take the trouble to consider the nature and properties of elastic fluids, -- of air, -- smoke, -- and vapour, -- and to examine the laws of their motions, and the necessary consequences of their being rarified by heat, will perceive that it would be as much a miracle if smoke should not rise in a Chimney, (all hindrances to its ascent being removed,) as that water should refuse to run in a syphon, or to descend in a river.

The whole mystery, therefore, of curing smoking Chimnies is comprised in this simple direction. -- find out and remove those local hindrances which forcibly prevent the smoke from following its natural tendency to go up the Chimney; or rather, to speak more accurately, which prevents its being forced up the Chimney by the pressure of the heavier air of the room.

Although the causes, by which the ascent of smoke in a Chimney may be obstructed, are various, yet that cause which will most commonly, and I may say almost universally be found to operate, is one which it is always very easy to discover, and as easy to remove, -- the bad construction of the Chimney in the neighbourhood of the Fire-place.

In the course all my experience and practice in curing smoking Chimnies, -- and I certainly have not had less than five hundred under my hands, and among them many which were thought to be quite incurable, -- I have never been obliged, except in one single instance, to have recourse to any other method of cure than merely reducing the Fire-place and the throat of the Chimney, or that part of it which lies immediately above the Fire-place, to a proper form, and just dimensions.

That my principles for constructing Fire-places are equally applicable to those which are designed for burning coal, as to those in which wood is burnt, has lately been abundantly proved by experiments made here in London; for of above an hundred and fifty Fire-places which have been altered in this city, under my direction, within these last two months, there is not one which has not answered perfectly well¹. -- And by several experiments which have been made with great care, and with the assistance