Analyjis of the Air . 2 j <? 
From thefe violent and fatal effeds of 
very noxious vapours on the refpiration and 
life of animals, we may fee how the refpi- 
ration is proportionably incommoded, when 
the air is loaded with lefler degrees of va- 
pours, which vapours do in fome meafure 
clog and lower the air’s elaflicity 5 which it 
beft regains by having thefe vapours dif- 
pelled by the ventilating motion of the 
free open air, which is rendered wholefome 
by the agitation of winds: Thus what we 
call a ciofe warm air, fuch as has been long 
confined in a room, without having the va- 
pours in it carried off by communicating 
with the open air, is apt to give us more 
or lefs uneafinefs, in proportion to the quan- 
tity of vapours which are floating in it* 
For which reafon the German Rowes, which 
heat the air in a room without a free 
admittance of frefli air to carry off the va- 
pours that are raifed, as alfo the modern 
invention to convey heated air into rooms 
thro* hot flues, feem not fo well contrived, 
to favour a free refpiration, as our common 
method of fires in open chimneys, which 
fires are continually carrying a large fire am 
of heated air out of the rooms up the chim- 
ney, which ftream muft necenarily be fup- 
S z plied 
