392 Dr. Ure's new experimental researches 
elastic force need not be equal to the first, in order to pro- 
duce the double tension. This view now given accords with 
the experiments of Mr. Watt, alluded to in the beginning 
of this memoir. He found that “ the latent heat of steam is 
less when it is produced under a greater pressure or in a 
more dense state ; and greater when it is produced under a 
less pressure or in a less dense state . ”* 
Berthollet thinks this fact so unaccountable, that he has 
been willing to discard it altogether. Whether the view 
which I have just opened, of the relation subsisting between 
the elastic force, density, and latent heat of different vapours, 
harmonize with chemical phenomena in general, I leave to 
others to determine. It certainly agrees with that unaccount- 
able fact. Whatever be the fate of the investigation of the 
general law now respectfully offered, the statement of Mr. 
Watt may be implicitly received under the sanction of his 
acknowledged sagacity and candour. 
CONCLUSION. 
To the theory of latent heat, which, like the hydrostatic 
paradox of Archimedes, might have remained for ages a 
barren, though beautiful proposition, the fertile genius of that 
philosopher gave all at once its noblest application, and most 
beneficial influence on human life, by his new steam engine. 
After him, many minds of the first order for science and 
ingenuity have offered schemes of farther improvement; 
Philos. Trans, vol. 84. p. 335. 
