298 Professor A. M. Wortliington [May 18, 



Fig. 12, up the sides of which an annular film of milk is carried 

 (Figs. 12 and 13), having been detached from the central mass, which 

 descends to be torn again, this time centrally into a well-marked 

 vortex ring. 



If we keep to the same size of drop and increase the fall to some- 

 thing over a yard, no great change occurs in the nature of the splash, 

 but the emergent column is rather higher and thinner and shows a 

 tendency to split into drops. 



When, however, we double the volume of the drop and raise the 

 height of fall to 52 inches, the splash of Series IV. is obtained, which 

 is beginning to assume quite a different character. The raised rim 

 of the previous scries is now developed into a hollow shell of consider- 

 able height, which tends to close over the drop. This shell or dome 

 is a characteristic feature of all splashes made by large drops falling 

 from a considerable height, and is extremely beautiful. In the 

 splash at present under consideration it does not always succeed in 

 closing permanently, but opens out as it subsides, and is followed by 

 the emergence of the drop (Fig. 8). In Fig. 9 the return wave over- 

 whelms the drop for an instant, but it is again seen at the summit of 

 the column in Fig. 10. 



But on other occasions the shell or dome of Figs. 4 and 5 closes 

 permanently over the imprisoned air, the liquid then flowing down 

 the sides, which become thinner and thinner, till at length we are left 

 with a large bubble floating on the water (see Series V.). It will 

 be observed that the flow of liquid down the sides is chiefly along 

 definite channels, which are probably determined by the arms thrown 

 up at an earlier stage. The bubble is generally creased by the weight 

 of the liquid along these channels. It must be remembered that the 

 base of the bubble is in a state of oscillation, and that the whole is 

 liable to burst at any moment, when such figures as 6 and 7 of the 

 previous series will be seen. 



Such is the history of the building of the bubbles which big rain- 

 drops leave on the smooth water of a lake, or pond, or puddle. It is 

 only the bigger drops that can do it, and reference to the number at 

 the side of Fig. 5 of Series IV. shows that the dome is raised in about 

 two-hundredths of a second. Should the domes fail to close, or should 

 they open again, we have the emergent columns which any attentive 

 observer will readily recognise, and which have never been better 

 described than by Mr. R. L. Stevenson, who, in his delightful 

 ■ Inland Voyage,' speaks of the surface of the Belgian canals along 

 which he was canoeing, as thrown up by the rain into " an infinity of 

 little crystal fountains." 



Very beautiful forms of the same type indeed, but different in 

 detail, are those produced by a drop of w r ater falling into the lighter 

 and more mobile liquid, petroleum. 



It will now be interesting to turn to the splash that is produced 

 when a solid sphere, such as a child's marble, falls into water. 



I found to my great surprise that the character of the splash at 



