16 



Mr. F. T. TroufcoD. On the Motion under [June 1, 



for doing this are the difference in density of the bubble and its 

 surface tension. An examination of the following tables will, I think, 

 justify this assumption. 



In Table II are exhibited the values of the " velocity reciprocal " 

 calculated for chloroform in this way. That is to say, the ascertained 

 values of the surface tension between chloroform and glycerine 

 (S = 12-1) and of the difference of their densities ( = O253) were 

 simply introduced into the expression we above obtained for the 

 velocity. In the third row for comparison is given the time taken 

 per centimetre found by actual experiment. 



Table II. Chloroform Glycerine. 



0-253. 



S = 12-1. 



In the following two tables the same is given for creasote and 

 mercury. 



Table III. Creasote Glycerine. 



-0-199. 



S = 2-05. 



TABLE IY. Mercury Glycerine. 



12-34. S = 370. 



For facility of comparison, the following table is selected from the 

 foregoing, with the addition of one other, giving particulars in the 

 case of two sized tubes of diameter 0'665 and T03 respectively. 



