THE SPLASH OF A DROP AND ALLIED PHENOMENA. 205 



The rising column, which is nearly cylindrical, breaks up into drops 

 before or during' its subse(iU(Mit descent into the licjuid. As it disap- 

 l)ears below the surface the outward and downwaid How causes a hollow 

 to be again fortiied, up the sides of which an annulus of milk is carried, 

 while the remainder descends to be torn again a second time into a 

 vortex ring, which, however, is liable to disturbance from tlie falling 

 in of the drops which once formed the upper part of the rebounding 

 column. 



It is not diflicult to recognize some features of this splash without any 

 ai)pii.ratus beyond a cui) of tea and a. simonfulof milk. Any drinker of 

 afternoon tea, after the tea is i)ourc(l out and before the milk is put in, 

 may let the milk fall into it drop by drop from 1 or 2 inches above it. 

 The rebounding column will be seen to consist almost entirely of milk, 

 and to break uj) into drops in the manner described, while the vortex 

 ring, whose core is of milk, may be seen to shoot down into the liquid. 

 But this is better observed by droi)ping ink into a tumbler of clear 

 water. 



Let us now increase the height of fall to 17 inches. Series III 

 exhibits the result (Plate V). All the characteristics of the last splash 

 are more strongly marked. In hg. 1 we have caught sight of the little 

 raised rim of the hollow before it has beaded, but in fig. 2 special 

 channels of easiest flow have been already determined. The number 

 of ribs and rays in this basket-shaped hollow seemed to vary a good 

 deal with difllerent drops, as also did the number of arms and lobes 

 seen in later figures, in a somewhat puzzling manner, and I have made 

 no attempt to select drawings which are in agreement in this respect. 

 It will be understood that these rays contain little or none of the 

 liquid of the drop which remains collected together in the middle. 

 Drops from these rays or from the larger arms and lobes of subsequent 

 figures are often thrown off high into the air. In figs. 3 and 4 the drop 

 is clean gone below the surface of the hollow, which is now deeper and 

 larger than before. The beautiful beaded annular edge then subsides, 

 and in fig. 5 we see the drop again, and in fig. (i it begins to emerge. 

 But although the drop has fallen from a, greater height than in the 

 previous splash, the energy of the impact, instead of being expeiuled 

 in raising the same amount of licpiid to a greater height, is now spent 

 in liffing a nmch thicker adherent column to about the same height 

 as in the last splash. There v/as sometimes noticed, as is seen in fig. 9, 

 a tendency in the water to How up past the milk, which, still compara- 

 tively unmixed with water, rides triumphant on the top of the emer- 

 gent column. The greater relative thickness of this column prevents 

 its splitting into drops, and figs. 10 and 11 show it descending beIo\y 

 the surface to form the hollovy of fig. 12, up the sides of which an annu- 

 lar film of milk is carried (figs. 12 and ].">), having been detatehed from 

 the central mass, which descends to be torn again, this time centrally 

 into a well-marked vortex ring. 



