388 Prof. Adeney and Mr. Becker : Determination of Rate of 



(b) Effect of temperature on the length of the bubble 

 in motion. 



A number o£ measurements were also made o£ the length 

 of the 15 c.c. bubble at different temperatures, and the 

 results are recorded here ; for, although they appear to have 

 no direct bearing on the object o£ the inquiry, they may be 

 of use in throwing light on the nature of the motion of the 

 bubble up the tube. 



A 15 c.c. bubble was drawn into the tube at each of the 

 temperatures given, and allowed to attain atmospheric 

 pressure at that temperature by opening the tap connecting 

 it with the air. The tube was then inverted several times 

 and the tap opened after each inversion to make sure that 

 the pressure in the bubble was atmospheric. The bubble 

 was then photographed, and the negative measured in 

 each case. 



Table III. 



Measurements of 15 c.c. Bubble at Different Temperatures.. 



Temperature. Length. 

 11° C. 16-15 



25° 15-98 



30° 15-91 



35° 15-85 



40° 15-81 



These measurements show that the length of the bubble 

 decreases with rise in temperature ; but since the volume 

 must be constant, the diameter must increase as the length 

 diminishes, hence the area will not be affected appreciably 

 by this change in length. 



(c) Effect of the area of the bubble on the rate of solution. 



To determine the effect of the area of the bubble on the 

 rate of solution a series of five duplicate experiments was 

 carried out at 25° C, using bubbles of 5, 7*5, 10, 12'5, and 

 15 c.c. The experiments with the first two bubbles were 

 made in a tube of 50 cm. length, as it was thought that too 

 large a fraction of the whole volume of air in the bubble would 

 be absorbed in one double passage up the 100 cm. tube. From 

 these experiments, the values of a and b w r ere calculated, as 

 described previously *, from the gniph obtained by plotting 

 the rate oil solution against air-content. 



* Part I. of this communication. 



