Tendency of Elastic Fluids to Diffusion. 9 



could intermix with each other independently of agitation. 

 The result seems to give it in the affirmative beyond a 

 doubt, contrary to the suggestion of Dr. Priestley, and 

 establishes this remarkable fact, that a lighter elastic fluid 

 cannot rest upon a heavier, as is the case with liquids ; but 

 they are constantly active in diffusing themselves through 

 each other till an equilibrium is effected, and that v^'ithout 

 any regard to their specific gravity, except so far as it acce- 

 lerates or retards the effect, according to circumstances. 



The only apparatus found necessary was a few phials, 

 and tubes with perforated corks : the tube mostly used was 

 one 10 inches long, and of l-20th of an inch bore ; in some 

 cases a tube of 30 inches in length and J -3d inch bore was 

 used : the phials held the gases that were subjects of ex- 

 periment, and the tube formed the connection. In all 

 cases the heavier gas was in the under phial, and the two 

 v/ere placed in a perpendicular position, and suffered to re- 

 main so during the experiment in a state of rest : thus cir- 

 cumstanced, it is evident that the effect of agitation was 

 sufficiently guarded against ; for, a tube almost capillary, 

 and ten inches long, could not be instrumental in propa- 

 gating an intermixture from a momentary commotion at 

 tlie commencement of each experiment. 



First Class. 



Carlonic Acid Gas, ivith Atmospheric Air, Hydrogenous y 



Azotic, and Niirozis Gases. 



1 . A pint phial filled with carbonic acid gas, the 30 inch 

 tube and an ounce phial, the tube and small phial being 

 filled with common air, were used at first. In one hour 

 the small phial was removed, and had acquired no sensible 

 quantity of acid gas, as appeared from agitating lime water 

 in it. In three hours it had the acid gas in great plenty, 

 instantly making lime water milky. After this it was re- 

 peatedly removed in the space of half an hour, and never 

 failed to exhibit signs of tlie acid gas. Things remaining 

 just the same, the upper phial was filled with the different 

 gases mentioned above repeatedly, and in half an hour 

 there wa-; always found acid sufficient to make the phial, 



or. e half 



