MR. J. S. TOWNSEND ON THE DIFFUSION OF IONS INTO OASES. 

 TABLE II. for Moist Air. 



149 



These results show that the mean rate of diffusion is only slightly altered by the 

 presence of moisture, but a large change is produced in the ratio of the coefficients of 

 diffusion of positive and negative ions. 



An experiment made with the apparatus shown in fig. 2 gave '034 for the mean 

 value of K. 



Oxygen. 



The oxygen which was used was taken from a cylinder which contained about 

 94 per cent, of oxygen, the other 6 per cent, being principally nitrogen. The rates 

 of diffusion of the ions through oxygen and air only differ by about 5 per cent., so 

 that the presence of 10 per cent, of air would only increase the rate of diffusion by 

 5 per cent. No correction need therefore be made for the presence of nitrogen in 

 the gas. 



The experiments on diffusion gave results exactly similar to those obtained with 

 air, except that the values of K were about 6 per cent, smaller. 



The coefficients of diffusion which were obtained for positive and negative ions in 

 dry oxygen are '025 and '0396 (mean -0323). 



The corresponding numbers for the moist gas are '0288 and '0358 (mean '0323). 



Carbonic Acid. 



The carbonic acid which was used was taken from a cylinder. As in the case of 

 oxygen, no correction need be made for the presence of a few per cent, of air mixed 



