404. 



Mr. T. Graham on the Absorption and 

 Table I. — Passage of Carbonic Acid, in seconds. 



Height of mer- 

 curial column 

 in diffusio- 

 meter. 



Experiment 1. 



Experiment 2. 



Experiment 3. 



millims. 

 748 

 723 

 698 



107 

 143 



102 

 138 



102 

 138 





250 



240 



240 



The passage of carbonic acid thus exhibited will be found to 

 be considerably more rapid than those of hydrogen and the two 

 other gases which follow : — 



Table II. 



Height of mer- 

 curial column 

 in diffusio- 

 meter. 



Passage, in seconds, 



of Hydrogen. 



of Oxygen. 



of Nitrogen. 



Exp. 1. 



Exp. 2. 



Exp. 1. 



Exp. 2. 



Exp. 1. 



Exp. 2. 



milliras. 

 748 

 723 

 698 



277 

 316 



270 

 323 



545 



. 727 



554 



722 



1413 

 1832 



3245 



1428 

 1850 



3278 





593 



593 



1272 



1276 



A single experiment, made at the same time, on the passage of 

 atmospheric air, gave times of 1318" and 1524" for the two 

 stages, or 2842" for the whole fall. The time of penetration of 

 air is therefore intermediate between that of oxygen and nitrogen 

 entering singly. 



Although such numbers do not possess the close uniformity 

 which appears in diffusion- and transpiration-experiments, for 

 reasons which will immediately appear, yet they give a compara- 

 tive estimate of the penetrativeness of the different gases through 

 rubber, which may be available for some practical purposes. 



Upon another occasion carbonic oxide and marsh-gas (C H 4 ) 

 were introduced into the comparison, the same film of rubber 

 remaining upon the diffusiometer : baroni. 768 millims., therm. 

 19°5 C. 



