[ 1 5 ° ] 
air be thrown over the fide of the vefifel, the fmoke, 
which is mixed with it, will fall to the ground, as if 
it was fo much water, the fixed air being heavier than 
common air. 
The red part of burning wood was extinguifhed in 
this air, but I could not perceive that a r&d-hot poker 
was fooner cooled in it. 
Fixed air does not inftantly mix with common air. 
Indeed, if it did, it could not be caught upon the 
fermenting liquor ; for a candle put under a large 
receiver, and immediately plunged very deep below 
the furface of the fixed air, will burn fome time. 
But vefiels with the fmalleft orifices, hanging with 
their mouths downwards in the fixed air, will in 
time have the common air, which they contain, per- 
fectly mixed with it. When the fermenting liquor 
is contained in vefiels clofe covered up, the fixed air 
is rendered much ftronger, and then it readily affedts 
the common air which is contiguous to it ; fo that, 
upon removing the cover, candles held at a con- 
fiderable diftance above the furface will infiantly go 
out. I have been told by the workmen, that this 
will fometimes be the cafe, when the candles are 
held more than half a yard above the mouth of the 
vefifel. 
Fixed air unites with the fmoke of refin, fulphur, 
and other eleClrical fubftances, as well as with the 
vapour of water j and yet, by holding the wire of a 
charged phial among thefe fumes, I could not make 
any eleCtrical atmofphere, which furprized me a 
good deal, as there was a large body of this fmoke, 
and it was fo confined, that it could not efcape me. 
]. alfo held foipe oil of vitriol in a glafs vefiel within 
