568  Onthe Force of Steam or Vapour 
sustained by the vapour, measured in inches of 
mercury. The force of aqueous vapour, at the 
same distance beyond the boiling point, or 322°, 
is equal to 137. 28, per table. Thus it appears 
_ that in every part of the scale on which experi- 
“ments have been made, the same iaw of force is 
observable with the vapour of ether as of water. 
Experiments on Spirit of Wine. 
By boiling a small portion of the spirit I used 
(about one cubic inch) in a phial, the thermo~ 
meter stood at 179° at the commencement; but 
by continuing the ebullition it acquired a greater 
heat. The reason is, the most evaporable part 
of the spirit flies off during the process of heat- 
ing, and the rest being a weaker compound, 
requires a stronger heat. The true point of 
ebullition, I believe, was nearly 175°—The 
force of the vapour from this spirit at the tem- 
perature of 212°, I found both by an open sy- 
phon tube and one hermetically sealed with 
atmospheric air upon the mercurial column, as 
with ether, to be equal to 585 inches of mercury, 
This rather exceeds the force of aqueous vapour 
at an equal distance from the boiling point ; but 
it is no more than may be attributed to unavoid- 
able little errors in such experiments. In a ba- 
rometer tube the spirituous vapour at 60°, ever 
the mercury, depresses the column about 1. 4 
or 1.5 inches, which is something less than the 
