80 Mr. Graham's Experimental Researches 



. . 31, 



. 121/ 



(5.) Receiver charged with 



Carbonic acid 

 Carbur. hydrogen 



Position, &c. as above. After four hours, 



Carbonic acid ... 23 



Carbur. hydrogen . . .71 

 Air .... . 58 



152 



152 

 Have left the receiver, 



Carbonic acid ... 8 



Carbur. hydrogen . . 50 



These three last experiments form a series. Suppose we 

 had a mixture of two gases, of the same densities as carbonic 

 acid and carburetted hydrogen, in equal volumes, but which 

 could not be separated from each other by chemical means. 

 Allow this gaseous mixture to diffuse for a certain time, as in 

 Experiment 3, into a gaseous or vaporous atmosphere, which 

 may afterwards be absorbed or condensed with facility. On 

 condensing this atmosphere, there would remain a mixture, 

 consisting of two parts of the light, and one of the heavy gas. 



By a similar diffusion of the mixture thus obtained, we 

 would procure a third mixture, consisting of four parts of the 

 light, and one of the heavy gas, (Experiment 4.) 



By a third diffusion, a mixture would be obtained of six or 

 seven of the light, and one of the heavy gas, (Experiment 5.) 



In this way a specimen of the light gas would at last be 

 eliminated, by a species of rectification, in a state of tolerable 

 purity. 



On the other hand, if a specimen of the dense gas be de- 

 sired, a converse series of operations must be pursued. What 

 remains in the receiver after diffusion must be preserved, 

 accumulated, and submitted again and again to diffusion. 



(6.) Receiver was charged with 



defiant gas . . . . 76] 

 Carburetted hydrogen . 76 ^ 



After four hours, contained, 



defiant gas . . . 47.75 



Carbur. hydrogen . . 41.40 



Air . . . . . 62.85 



152 



