1885.] On the Formation of Vortex Rings by Drops. 



433 



and persists until so much of the drop has been whirled off into the 

 following vortex that the form a is reached again, and the velocity 

 of fall never attains such a value as to bring about the thinning out 

 of the edges. If a still larger drop is let fall, the forms C l3 C 2 , and C 3 

 are assumed, in which the thin cylindrical part at the edge is at first 

 vibrating up and down, until the steady phase, C 3 , is reached : this 

 will by degrees be reduced to the form b, but the column of paraffin 

 was not long enough for us to observe the final form a. If a still 

 larger drop of oleate is used, the vibrations of the cylindrical part, d, 

 are so great that the drop is torn asunder and such disturbance is 

 produced in the column that a steady fall is not attained. These 

 results may be obtained by increasing the strength of the oleate 

 solution and keeping the size of the drop constant. 



One more case of interest may be described, namely, that of drops 



