92 Prof. Adeney and Mr. Becker on the Rate of Solution 



of the atmosphere. In order to verify this point a further 

 experiment was made. 



The effect of the humidity of the air in contact with the 

 water on the rate of solution is shown by the following 

 experiment : — 



Four tubes, each 320 mm. long and 40 mm. diameter, 

 were placed in a thermostat after being filled with de-aerated 

 water. Three of these tubes, after 50 c.c. water had been 

 withdrawn from each, were then connected by means of 

 rubber corks and glass tubing, so that a current of air could 

 be drawn through the series. The fourth tube was left open 

 to the atmosphere. 



Unfiltered air was drawn through the air-space of tube 1, 

 and then through two U-tubes containing calcium chloride, 

 from which the dried air passed into the air-space of tube 2, 

 whence it passed directly into the air-space of tube 3. Thus 

 the air in tube 2 was much drier than that in the atmosphere ; 

 and that in tube 3 was more moist, and probably nearly 

 saturated with aqueous vapour. 



The results are given in the following table : — 



Table III. 



Experiment with air of different degrees of humidity. 

 Temperature of Experiment, 15° 0. 



No. of 

 tube. 



Area. 



Vol. of 

 water. 



Time of 

 exposure. 



Degree of 

 aeration. 



Value of b. 



Yal 



ue of /. 



1 



12-56 



340 c.c. 



43 bra. 



41-5 % 



•0125 





•34 



2 



1225 



323 „ 



44 „ 



63-2 „ 



-023 





•61 



3 



12-25 



327 „ 



44-5,, 



313 „ 



•009 





•23 



4 



12-25 



370 „ 



42 „ 



32-7 „ 



•010 





•29 



It should be noted that tube 4 was exposed in the middle 

 of the thermostat at a time when the humidity of the air was 

 considerable. Hence the value /is rather low. 



On examining these results it will be noticed that the tube 

 through which the dried air was drawn shows the largest 

 proportion of dissolved air, although the time of exposure 

 w r as practically the same in each case. In fact, the figures 

 show that the water in this tube absorbed more than twice 

 as much air as that in the tube through which the moist air 

 was drawn. 



In order to reduce these experiments to a basis which will 

 allow comparison with the previous experiments, the values 

 of / have been calculated in the usual way, assuming that 



