Prof. Hosking on Ventilation. 253 
ness, the process does not fulfill the condition as to wholesome- 
ness, and this is the case, when the outer air is admitted at or 
near to the ceiling to take up warmth from the spent and heated 
atmosphere of the higher levels. Having undergone this process, 
it is not the fresh air that comes warmed to its inmates, but a 
mixture of fresh and foul air that cannot be agreeable to any in- 
mate conscious of the nature of the compound. 
he endeavor on the present occasion was to show how the 
familiar fire of an apartment may be made to fulfill all the condi- 
tions necessary to obtain in-door ventilation, to the extent at 
least of the apartment in which the fire may be maintained, and 
while it is maintained. 
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 
open only for the register flap or valve over the: fire itself. Bx- 
ternal air is to be admitted to the closed chambers thus obtained 
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 o 
facility so provided the fire will readily avail itself to the aboli- 
tion of all illicit draughts. But the air in passing through the alr- 
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 1 
that condition it reaches the apartment: poe 
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 com- 
Pel the fire to allow what is not necessary to it to” ‘the 
