78 



THE DIFFUSION OF GASES THROUGH 



55. The Same, Continued. — The dilution of the preceding solution 

 with about an equal bulk of water showed the density p= 1.0435 ^t 21°, or 

 4.83 grams in 100 grams of solution, 5.1 grams in 100 grams of water, the 

 vapor pressure being 7r' = 7r (i —0.0 10). 



The record of results is given in table 36 and fig. 31, and is throughout 

 reasonably regular, particularly after the weekty period of observations 

 has been installed. The diffusion constants are 



^'0 = 0.00875 c.c. day or 10^ = 0.244. 

 which is still far removed from water. 



Table 36. — Air into air through BaCIj solution (5.1 grams in 100 grams water). Single- 

 tube vessel. Constants as in table 34. p^= 1.0435 at 21°. 



Date. 



Barom- 

 eter. 



t 



H 



vo 



63-39 



61 .70 



60.78 



60.94 



60.45 

 60.37 



60.32 



3.248 



3.164 

 3. 118 



3. 126 



3.099 



3 002 



3.088 



Date. 



Barom- 

 eter. 



H 



Jan. 



2. 



3- 

 10. 



•7- 

 24. 



3'- 



60.07 

 60. 14 



58.58 



57.16 

 56.57 



55-74 



3.074 

 3.077 

 3.002 



2.931 



2.898 

 2.855 



2-7 



See. Zi 26 & Jcm,5 10 W 



Fig. 31. — Chart showing loss of standard volumes of 

 gas in diver in lapse of days. Diffusion of air through 

 BaCl2 solution. 



56. Diffusion of Air into Air Through K2SO4 Solution. — This solution 

 is the first of the sulphates and is to be compared with sodic sulphate and 

 possibly with the alums. The solution of K0SO4 showed a density of p„ = 

 1.065 ^t 23°, corresponding therefore to 8 grams of K2SO4 in 100 grams 

 of solution or 8.7 grams in 100 grams of water. The vapor pressure was 

 taken as 7r' = 77-(i— 0.017). The results are given in table 37 and fig. 32 a. 



A line drawn through the observations corresponds to the following slope: 



^0 = 0.0137 c.c./day or 10^ = 0.401 



The small effect is in keeping with the essentially dilute solution of a not 

 very soluble salt. 



57. The Same, Continued. — This solution 



of 



KoSO. was diluted to 



about one-half and the resulting density found to be 1.03 15 at 19°, which is 

 equivalent to 4 grams of K2SO4 in 100 grams of solution or 4.2 grams in 100 

 grams of water. Hence the vapor pressures are -' = 71(1—0.008). The 

 record of results is given in table 38 and fig. 32 b. 

 The mean diffusion rates correspond to 



z'o = 0.0100 c.c./day or io^°k = 0.322 



