194 New experimental Researches 
o 32340 gr. of water. The thermometer in the experiment rose’ 
3°. 3° —0°:266 = 2-734, 2°734 x 161°7 = 442° =the latent heat 
of alcoholic vapour in eyuilibrio with the atmospheric pressure. 
By a similar process of calculation the latent heat of the other 
vapours was determined. 
General Table of latent Heat of Vapours. 
Vapour of water at its boiling point 967° 
alcohol sf as 442 . 
ether le es 302-379 
petroleum aby ine 177°87 
oil of turpentine’ “pe 177-87 
nitric acid “42 Ale 531°99 
liquid ammonia a 837-28 
vinegar oe zt 87500 
From the phenomena exhibited in the mechanical condensa- 
tion and rarefaction of gases and vapours, as well as from their 
general constitution, it may be inferred, that an intimate and 
necessary connexion subsists between their latent heat, elastic’ 
force, and specific weight or density. 
Hence, when their tension is the same, it appears reasonable 
to suppose that the product of their densities into their quantities 
of latent heat will also be the same. Repulsive energy will be, 
proportional to the quantity of heat, the repulsive power con- 
densed or contained in a given space. Thus if the space left for 
its interposition or lodgment be in one vapour a half ora third of 
the amount of the space in another, we ought to find equal ten-, 
sion produced in the former case, by a half or a third of the la-. 
tent heat required for the latter. 
As the principle, | have reason to suppose, is somewhat new,.- 
let us illustrate it by an application to the three vapours in the 
above list which are most homogeneous, or at any rate best un-_ 
derstood ; those of alcohol, ether and water. 
Aqueous vapour of an elastic force balancing the atmospheric: 
pressure has a specific gravity, compared to air, by the accurate & 
experiments of Gay Lussac, of 10 to 16. 
For facility of comparison let us call the steam of water unity, 
or 1-00; then the specific gravity of the vapour of pure ether is. 
4:00, while the specific gravity of the vapour of absolute alcohol 
is 2- 60. ; 
But the vapour of ether, whose boiling point is not 100°, but 
112°, like the above ether, contains some alcohol ; hence, we 
must accordingly diminish a little the specific gravity of its va- 
pour. 
It will then become instead of 4:00 ve “ B55. 
° Alcohol 
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