-37- 283 



It Is to be noted that x = 1 corresponds to no 

 free surface (c = ^'o )» while x = corresponds to a 

 point midway between the free surface and the rigid bottom. 



An interesting result is that F(x) = when x = 1/3) 

 so that the influence of the free surface on the period of 

 the bubble cancels the Influence of the rigid bottom. 



