82 



THE DIFFUSION OF GASES THROUGH 



( i —0.255). The curve obtained for the progress of diffusion is a line nearly 

 horizontal, showing a liquid all but impervious so far as the air molecule is 

 concerned. The slopes of the curve, table 42, fig. 35 a, correspond to 



v = 0.00125 c - c - day or io 10 /; = 0.045 



the smallest value thus far obtained. Though a comparison with A1C1 3 

 is intended, it must be remembered that the apparatus is the one with the 

 long diver and liable to show relatively small results. 



Table 42. — Air-air through FeCl 3 solution (37.5 grams in 100 grams water). Vessel H 

 (single tube). p w = 1 .2510 at 22°. Constants as in table 23. 



Date. 



Barom- 

 eter. 



t 



II 



v B 



Date. 



Barom- 

 eter. 



t 



II 



Z'O 



Dec. 



2 



I 

 . 76.60 



O 



'7-5 



67-47 



3.823 



Dee. 16. . 



75.40 





 17.9 



67-85 



3.840 





3 



• 76.45 



17 



3 



67.61 



3 



833 



17.. 



76 



45 



'7 



8 



67.77 



3-837 





4 



. 76.30 



•7 



5 



67.56 



3 



828 



18.. 



76 



40 



17 



9 



67.51 



3.821 





5 



. 77.06 



'7 



8 



67.66 



3 



830 



19. . 



1 74 



34 



18 







67.72 



3.83. 





6 



75-75 



18 



2 



67.78 



3 



832 



20. . 



75 



88 



18 



2 



67.58 



3.821 





7 



• 76.14 



18 



6 



67.85 



3 



832 



21 . . 



76 



57 



18 



1 



67.56 



3.821 





9 



.| 76.28 



18 



6 



67.99 



3 



840 



23-- 



76 



75 



'7 



9 



67.42 



3.816 





10 



• 76.33 



18 



6 



67.97 



3 



838 



24.. 



75 



70 



'7 



8 



67.42 



3.8.7 





1 1 



• 75-92 



18 



2 



68.03 



3 



846 



26. . 



77 



10 



17 



8 



67.23 



3.806 





12 



. 76.16 



18 



4 



67.99 



3 



841 



28. . 



75 



50 



17 



9 



67.36 



3.812 





13 



• 77-io 



18 







67.95 



3 



844 



30. . 



75 



74 



18 



1 



67.38 



3. 811 





'4 



- 76.74 



17.9 



68.06 



3.852 





I 







! 



«Wr 



■3-7 ^L 

 Fig. 35 a, b. 



B 



Jan.ti 



-Charts showing loss of standard volumes of gas in diver in lapse of days. 

 Diffusion of air through FeCl 3 solution. 



62. The Same, Continued. — The preceding solution was now diluted 

 with an equal bulk of water. The density was thus reduced to 1.1260 at 

 24 , corresponding to about 14.3 grams in 100 grams of solution or 16.7 

 grams in 100 grams of water. Thus the provisional vapor pressures are 

 7r' = 7r(i —0.095). The^ record of results is contained in table 43 and fig. 35 b. 



Table 43.— Air into air through FeCl 3 solution (16.7 grams in 100 grams water). 

 Vessel II. Constants as in table 42. p w = 1.1260 at 24°. 



Date B arom- , 

 ^ ate - eter. l 



II 



Vo 



Date. 



Barom- 

 eter. 



t 



H 



4-779 



4.762 



Jan. 11.. 76.28 

 17.. 76.54 



O 



17.9 

 17.9 



69.61 

 69.26 



4.823 

 4-799 



Jan. 24. . 

 31.. 



76. 10 

 76.17 







18.2 

 18.2 



69.00 

 68.76 



The rates of diffusion correspond to 



» = 0.00275 c.c./day or io 10 k = 0.094 



Observations were taken but once a week with an obvious advantage 

 to the smoothness of the curve. The ratio is here remarkably linear. 



