Dialytic Separation of Gases by Colloid Septa. 405 



Table III. 



Height of 

 mercurial 

 column in 

 diffusio- 

 meter. 



Passage, in seconds, 



of Carbonic 

 oxide. 



of Hydrogen. 



of Carbonic acid. 



of Marsh-gas 

 (CH*). 



Exp. 1. 



Exp. 2. 



Exp. 1. 



Exp. 2. 



Exp. 1. 



Exp. 2. 



Exp. 3. 



Exp. 1. 



Exp. 2. 



raillims. 

 748 

 723 

 698 



1620 

 1920 



1631 

 1924 



435 

 505 



434 

 511 



125 

 170 



119 

 169 



117 

 172 



803 

 1009 



821 

 1045 





3540 



3555 



940 



945 



295 



288 



289 



1812 



1866 



The results may be summed up by deducing the times in 

 which a constant volume of the various gases is transmitted by 

 the rubber, — the time of passage of carbonic acid, which is the 

 shortest, being taken as unity for the sake of comparison. 



Penetration of rubber by equal volumes of Gas. 



Time. 



Carbonic acid .... 1 



Hydrogen 2*470 



Oxygen 5-316 



Marsh-gas (C H 4 ) . . . 6*326 



Atmospheric air . . . 11*850 



Carbonic oxide .... 12*203 



Nitrogen 13*585 



Or, with the times taken equal, the volume of each gas which 

 passes then expresses the velocity of penetration. 



Penetration of rubber in equal times. 



Velocity. 



Nitrogen 1 



Carbonic oxide . . . . 1*113 

 Atmospheric air . . . 1*149 

 Marsh-gas (C H 4 ) . . . 2*148 



Oxygen 2*556 



Hydrogen 5*500 



Carbonic acid . . . . 13*585 



Considering the circumstances in which the gases pass through 

 the sheet of rubber into a vacuum, it is not to be expected that 

 any relation will be found among the preceding numbers, as be- 

 tween the coefficients of diffusion in gases. The first absorption 



