S. Webber on Ventilation. 383 
could be — supplied by such means-and all up draft of air 
from the room through it prevented, this would not abolish such 
draughts theotigh these crevices, since he strenuously insists ona 
room from the sides of the fire-place should fully supply the de- 
mand. Moreover by this arrangement the impure and denser air 
at the lower levels of the apartment would have no escape pro- 
vided for it, and would thus have a tendency to accumulate. 
It would apparently be much better to have the fire as in or- 
dinary cases depend wholly for its supply of air upon the general 
stock contained in the room, for as it would draw it principally 
from the lower levels, it would thus, while supplying itself wit 
what would support combustion, heat, rarify, and send up the 
chimney, the impure or non-combustible portions mingle with it, 
and thus the carbonic acid, the worst of all, would be carried off 
as fast as formed, and if all the fresh air brought into the hollows 
surrounding the fire were thrown directly into the room there: 
would be as little chance of “illicit draughts” as in his mode. 
The upper ventilator too would not need to be so large, and there~ 
fore less warmth would detape, and a better economy of one 
e 
A favorite mode of warming rooms of late has been ‘sims of 
conveying into them a current of fresh air heated over a furnace 
in the cellar or basement of the house, and conveyed by appro- 
priate pipes into the different apartments where it may be re- 
quired, generally throngh an opening in the floor provided with 
a register grate, against which the pipe abuts, and which serves 
to regulate the amount transmitted. Such rooms require ventil« 
ating apertures, communicating with a chimney sion for the 
escape of the impure air generated’in the room. he warmth of 
the pure air issuing from the register. is generally so ous that it 
rises at once to the top of the room, bearing down under it the 
air of the room, and the less heated air of the respiration to a 
very considerable extent, - —* greater —— 
the air favors its descent. From this cause the lower body of 
air is the most impure as in wa cases, ail perhaps pee 
dedly so, and of course the need of a ventilating aperture on a 
low level is strikingly evident; yet we have seen in such rooms 
only one ventilator, and that placed just below the ceiling, as if 
to provide an escape for the warm fresh air just introduced, and 
to favor as long as possible the accumulation and retention of 
carbonic acid. If there be but one ventilator in a room so 
warmed it should be near the floor. Indeed naan» ed 
Such a situation 
