LIQUIDS AND ALLIED EXPERIMENTS. 



71 



in 100 grams of water. The vapor pressure was put 7r' = 7r(i —0.017). The 

 chart shows the results, which are unfortunately irregular for some unex- 

 plained reason, there being in the usual way a very slow adjustment to the 

 equilibrium conditions, after which the gas diffuses at a fairly regular rate. 

 The diffusion constants are (vessel B), 



Vq — 0.0222 c.c./day or 10^*^^ = 0.423 



a reasonable ad\ance on the former rates. The three curves for KCl solu- 

 tions show that not until after the lapse of two weeks do definite rates 

 appear. These essentially final rates are the ones taken. In each case 

 there seems to be an adjustment of the gas (Oo, Ng), which actually diffuses, 

 to the solution. 



46. The Same, Continued. — On further dilution with about an equal 

 volume of water the density of the solution was p=i.oi7o at 21°, corre- 

 sponding to 2.65 grams in 100 grams of solution, or 2.7 grams in 100 grams 

 of water. Thus the vapor pressure became 7r' = 7r(i — o.oio). 



The progress of the diffusion is given in table 27 and fig. 25. The latter 

 shows marked irregularity at the beginning (as usual), but the curve be- 

 comes fairly smooth when daily observations are replaced by weekly obser- 

 vations. Clearly, therefore, the daily churning up of the solution during 

 observation, usually at a relatively high temperature, is unfavorable to a 

 steady progress of results. The locus, however, is not quite straight, for 

 reasons which can not be inferred, as temperature was fairly constant. 



T.\Bi.E 27. — Air into air through KCl solution (2.7 grams in 100 grams water). Con- 

 stants as in table 24. Vessel B. p,(,= 1.0170 at 21°. 



SiecZI 26 in^') 10 i5 «0 Z5 39 

 Fig. 25. — Chart showing loss of standard volumes of 



gas in diver in lapse of days, 

 through KCl solution. 



Diffusion of air 



