Of Chimney Fireplaces. 5 1 7 



throat that is in front, or nearest to the room, should 

 he neatly cleaned off, and its surface made quite regular 

 and smooth. 



This may easily be done by covering it with a coat 

 of plaster, which may be made thicker or thinner in 

 different parts as may be necessary in order to bring the 

 breast of the chimney to be of the proper form. 



With regard to the form of the breast of a chimney, 

 this is a matter of very great importance, and which 

 ought always to be particularly attended to. The worst 

 form it can have is that of a vertical plane, or upright 

 flat ; and next to this, the worst form is an inclined 

 plane. Both these forms cause the current of warm air 

 from the room, which will, in spite of every precaution, 

 sometimes find its way into the chimney, to cross upon 

 the current of smoke, which rises from the fire, in a 

 manner most likely to embarrass it in its ascent, and 

 drive it back. The inclined plane which is formed by a 

 flat register placed in the throat of a chimney produces 

 the same effects ; and this is one reason, among many 

 others, which have induced me to disapprove of register 

 stoves. 



The current of air, which, passing under the mantle, 

 gets into the chimney, should be made gradually to bend 

 its course upwards, by which means it will unite quietly 

 with the ascending current of smoke, and will be less 

 likely to check it, or force it back into the room. Now 

 this may be effected with the greatest ease and certainty, 

 merely by rounding off the breast of the chimney or back 

 part of the mantle, instead of leaving it flat, or full of 

 holes and corners ; and this, of course, ought always to 

 be done. 



I have hitherto given no precise directions in regard 



