392 RELATIVE ATTRACTIONS OF 
from a high pressure boiler loaded with forty 
pounds upon the square inch. He says that it 
serves, by powerful agitation, not only to mix the 
different gaseous molecules intimately together, 
but to impel them against each other, and thus 
bring them within the sphere of their mutual 
chemical attraction. The mechanical commotion 
which must be produced, by the sudden freedom 
from confinement of a body having the elastic 
force of steam under a pressure of forty pounds 
upon the square inch, would, I admit, be advan- 
tageous if sufficient agitation of the gaseous 
molecules was not derivable from another source: 
but, when we consider the comparatively enor- 
mous bulk of the aeriform bodies which has to be 
condensed into one cubic inch in the formation of 
a cubic inch of sulphuric acid, or of the crystalline 
compound produced from sulphurous acid, nitrous 
acid, and a minimum of water, surely our imagin- 
ation will not allow us to suppose that the agita- 
tion which takes place, in tending to restore the 
equilibrium disturbed by such condensation, is not 
sufficient to intermix and diffuse amongst each 
other the several kinds of gaseous molecules, 
leaving out of consideration the general law of the 
diffusion of aeriform bodies experimentally illus- 
trated by Dr. Dalton, in the Manchester Memoirs, 
