on some of the leading doctrines of caloric , &c. 391 
Hence ~ of latent heat, existing in ethereal vapour, will 
occupy a proportional space, be equally condensed or possess 
the same tension with — in alcoholic, and — in aqueous 
vapour. 
A small modification will no doubt be introduced by the 
difference of the thermometric tensions, or sensible heats, 
under the same elastic force. Common steam, for example, 
may be considered as deriving its total elastic energy from 
the latent heat multiplied into the specific gravity + 
thermometric tension. 
Hence the elastic force of water, or 
E w = 970° X 1.00 4= 212° =2 1182 
E g = 302° x 3.55 + = 1184 
E ai = 440° x 2.30 + 175° =a 1185 
Three equations which yield, according to my general 
proposition, equal quantities ; or of which the differences are 
inconsiderable, and undeserving of notice. 
Neither the specific heats nor specific gravities of the 
other vapours are ascertained with sufficient precision to 
enable us to subject them to calculation. 
General equation F — l x d + T = © : L, latent heat, D, 
density, T, temperature corresponding to F. 
When the elastic forces of vapours are doubled, or when 
they sustain a double pressure, their interstices are proportion- 
ally diminished. We may consider them now as in the condi- 
tion of vapours possessed of greater specific gravities. Hence, 
the second portion of heat introduced to give double the 
