80 NOTICES OF THE MEETINGS (May 23, 
to obtain in-door ventilation, to the extent at least of the apart- 
ment in which the fire may be maintained, and while it is maintained. 
A fire in an ordinary grate establishes a draught in the flue 
over it with power according to its own intensity, and it acts 
with the same effect, at least, upon the air within its reach, for 
the means which enable it to establish and keep up the draught in 
the flue. The fire necessarily heats the grate in which it is kept 
up, and the materials of which grates are composed being necessarily 
incombustible, and being also ready recipients and conductors 
of heat, they will impart heat to whatever may be brought into 
contact with them. 
It is supposed that the case containing the body of the grate is 
set on an iron or stone hearth in the chimney recess, free of the 
sides and back except as to the joints in front. Let all communi- 
cation between the chamber so formed about the back and sides of 
the grate and the chimney flue be shut off by an iron plate, open only 
for the register flap or valve over the fire itself. External air is to 
be admitted to the closed chambers thus obtained about the grate 
by a tube or channel leading through the nearest and most con- 
venient outer wall of the building and between the joists of 
the floor of the room, to and under the outer hearth or slab 
before the fire, and so to and under the back hearth in which 
sufficient holes may be made to allow the air entering by the tube 
or channel to rise into the chamber about the fire-box or grate. 
Openings taking any form that may be agreeable are to be made 
through the cheeks of the grate into the air-chamber at the level 
of the hearth. In this manner will be provided a free inlet for 
the outer air to the fire-place and to the fire, and of the facility 
so provided the fire will readily avail itself to the abolition of all 
illicit draughts. But the air in passing through the air chamber in 
its way to the fire which draws it, is drawn over the heated surfaces 
of the grate and it thus becomes warmed, and in that condition 
it reaches the apartment. 
An upright metal plate set up behind the openings through cheeks 
of the grate, but clear of them, will bend the current of warmed air in 
its passage through the inlet holes, and thus compel the fire to allow 
what is not necessary to it to pass into the room ; and if the opening 
over the fire to the flue be reduced to the real want of the fire, the 
consumption of air by the fire will not be so great as may be supposed, 
and there will remain a supply of tempered air waiting only an induce- 
ment to enter for the use of the inmates of the apartment. An opening 
directly from the room into the flue upon which the fire is acting with 
a draught more or less strong, at a high level in the room, will afford 
this inducement; it will allow the draught in the flue to act upon the 
heated and spent air under the ceiling, and draw it off ; and in doing 
so will induce a flow of the fresh and tempered air from about the 
body of the grate into the room. 
The mode thus indicated of increasing the effect of the familiar fire, 
