i&4 
recfcs its being made to pass in its entrance through winding 
cavities made behind the iron back and sides of the fire¬ 
place, and under the iron hearth plate ; in which cavities it 
will be warmed and even heated, so as to contribute much, 
instead of cooling, to the warming of the room. This inven¬ 
tion is excellent in itself and may be used with advantage in 
building new houses ; because the chimneys may be so dis¬ 
posed as to admit conveniently the cold air to enter such 
passages ; but in houses built without such views, the chim¬ 
neys are often so situated as not to afford that convenience, 
without great and expensive alterations.- The difficulty 
here suggested by Doctor Franklin seems to me to be alto¬ 
gether avoided in the method of putting up such fire-places, 
proposed by Doctor Cooper. The plates may be adapted 
to almost every common fire-place, and all that is necessary 
in addition to this, is to make a perforation through each of 
the jambs, and one through the wall on which the hearth 
rests ; from which last a tube is extended, commonly under 
the floor, to the most convenient place where it can reach 
the external air. Many of these fire-places have already 
been introduced into a variety of rooms in this city, at an 
expense comparatively small, and without any difficulty, in 
adapting them to every common fire-place. Two of them 
have been lately made in the Senate chamber, by the com¬ 
missioners superintending the building of the Capitol. And 
on the whole, considering the prevailing taste for open fire?- 
places on the Rumford model, connected with the comfort 
to be derived from admitting warm, instead of cold air into 
rooms, and the great economy of fuel in consequence of that 
arrangement, I am persuaded that this fire-place is the best 
that has hitherto been contrived ; and is well calculated for 
general use. The essence of the improvement made by 
Doctor Cooper consists in the afip.lica.tion of Franklin’s prin¬ 
ciple to Rumford’s fire-place, combining all the advantages of 
both, which had never before been successfully accom¬ 
plished. 
