S. Webber on Ventilation. 189 
as this part of the system is the first almost to manifest the effects 
of blood not duly purified in the lungs. 
1e common mode of admitting air into too warm a room by 
letting down the upper sash of a window, where it can be done, 
in preference to raising the lower, is founded upon this princi- 
ple, and is perfectly correct. The mode however is somewhat 
defective, as the air is admitted in too large a body and with too 
strong a current, except for excessive cases, and by producing too 
sudden a check to perspiration and to the secretions of the mu- 
cous membranes of the air-passages, is apt to produce inflamma- 
tory affections of the head and throat. Were it to pass through 
a sheet of wire gauze or perforated plate of thin metal, its force 
and intensity would be much lessened, as it would be divided 
into numerous minute currents, and instead of descending like a 
cataract, would fall quietly like spray or mist, mixjng intimately 
ith the warm air and gently cooling it, and refreshing and cool- 
ing without chilling,*the heads, necks and air-passages of the per- 
Sons in the room. Were a space of a foot in depth in the upper 
part of one or two windows with a moveable upper sash thus 
provided, (and this might easily be done, and so as even to be 
ornamental, ) no better ventilators for supplying cool fresh air to an 
6 oe 
tilators and the means of warming recommended, there would be 
No great difficulty to be encountered in keeping the desirable de- 
gree of warmth and purity of the air in any but hot and sultry 
Weather, when of course the temperature of the external air must 
12 some degree limit the amount of coolness to be obtained by 
Ventilation. 
d . - 
bad. effect upon furniture not thoroughly seasoned and dried in 
the making, causing it to shrink, crack, and warp; and even fur- 
hiture made in a moist or cool season of the year, though of ap- 
parently well seasoned wood, will under the influence of a stead- 
ily warmed room, where the heat is kept up to summer tempera- 
