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



421 



We have observed a great number of drops at many different points 

 of their fall through the column into which they have been dropped, 

 and at any given instant have found that a few definite forms repeat 

 themselves. Thus we are led to believe that the conditions of fall, 

 though seemingly not altered, vary in a few definite ways, so that 

 successive drops do not always pass through the same series of phases. 

 Indeed, simple observation in continuous light shows clearly differences 

 in the perfection of: formation of the rings under apparently similar 

 conditions. We have found a set of forms for a particular instant, 

 and from the various sets taken for successive instants, separated by 

 small intervals, we have picked out series of forms which strike us as 

 continuously derivable from one another. 



Fig. 4. 



