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



fig. 2, a straight line graph is obtained which intersects the- 

 axis of x in a point lying to the left of the origin. Hence 

 the absorption is not directly proportional to the area of the 

 bubble. This appears to be due to the fact that the con- 

 ditions which apply to the cylindrical portion of the bubble 



Fig. 2. 



•3 * 5 



.c: 



i-4 





... . 











s 

























^ 



Q/' 













s 



/ 

































* 









...J 



50 



60 



10 20 30 40 



Area in sq. cm. 

 Values of b plotted against area of bubble. 



70 



8& 



do not hold for the hemispherical head. The rate at which 

 the water streams past the head of the bubble is much less 

 than that at which it passes down the cylindrical portion 

 of it ; hence the absorption due to the head of the bubble is 

 greater than might be expected from its area. These two 

 effects are differentiated by measuring the rate of absorption 

 for a number of different bubbles ; because, since the effect 

 of the head of the bubble is the same in each case, the 

 variation in absorption must be due to variation in the area 

 of the cylindrical portion. Hence the graph shows the rate 

 at which the value of b increases with increasing cylindrical 

 area. By producing the graph until it cuts the .r-axis we 

 obtain a constant correction for the head of the bubble, 

 which, when added to the calculated area of the bubble r 

 gives the effective area when the absorption is uniform all 

 over the surface. 



The value of the intercept on the ^-axis is 15 sq. cm. ; 

 hence this amount must be added to the area of each bubble. 



