73 



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 a * 21 , or 

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

 vapor pressure being ir' = tt (1 —0.0 10). 



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



reasonably regular, particularly after the weekly period of observations 



has been installed. The diffusion constants are 



t'o = o. 00875 c.c. day or io 10 ;. = 0.244. 



which is still far removed from water. 



Table 36. — Air into air through BaCl 2 solution (5.1 grams in 100 grams water). Single- 

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



Date. 



Barom- ; 



eter. 1 



t 



H 



'''0 



Date. 



Barom- 

 eter. 



t 



H 



Vc 



Dee. 21 . 



; 76.57 





 '7-5 



63.39 



3.248 



Jan. 2.. 



76.87 





 17.9 



60.07 



3-074 



23- 



: 76.75 ! 



■7-3 



61 .70 



3.164 



3- • 



73.93 



1S.0 



60. 14 



3-077 



26. 



77.10 



17. 1 



60.78 



3. 118 



JO. . 



77-35 



'7-5 



58.58 



3.002 



28. 



75-50 



17.1 



60.94 



3. 126 



17.. 



76.54 



17.2 



57.16 



2.931 



30. 



75-74 



'7-3 



60.45 



3.099 



24.. 



76.10 



17.0 



56.57 



2.898 



3i- 



\ 76.34 j 



17.6 



60.37 



3.092 



31. . 



76.17 



17.6 



55-74 



2.855 



Jan. 1 . 



76 . 1 



.7-8 



60.32 



3.088 















hi dan. 5 



10 15 



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

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

 BaCl 2 solution. 



56. Diffusion of Air into Air Through K,S0 4 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 K 2 S0 4 show T ed a density of p w = 

 1.065 at 2 3°» corresponding therefore to 8 grams of K 2 S0 4 in 100 grams 

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

 taken as x' = x(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 io 10 k = o.4oi 

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

 very soluble salt. 



57. The Same, Continued. — -This solution of K 2 S0 4 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 K,S0 4 in 100 grams of solution or 4.2 grams in 100 

 grams of water. Hence the vapor pressures are 7r' = 7r(i —0.008). The 

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



The mean diffusion rates correspond to 



v = 0.0100 c.c. day or io 10 k = 0.322 



