348 On Impact with a Liquid Surface. [Feb. 16, 



The time interval between successive stages of the disturbance can 

 be measured to within a few thousandths of a second. 



The significant portion of the whole series of changes in most of the 

 splashes observed is comprised within about one-third of a second. 

 The impact of both solid and liquid spheres has been studied, and is 

 illustrated by several series of drawings which accompany the paper. 



Milk drops falling into water were found to produce a similar 

 disturbance to that resulting from the impact of similar water drops, 

 and were used for the sake of distinguishing the original liquid of the 

 drop from that into which it fell. With a drop about 5 millims. in 

 diameter, falling from less than 1 metre, an annular rim is raised at 

 the first moment of impact, bounding a hollow which is afterwards 

 characterised by regularly disposed radial ribs and arms, at the 

 bottom of which the drop descends, passing below the surface and 

 becoming completely submerged, to emerge again at the head of a 

 column of adherent liquid, but with its upper portion apparently 

 unwetted by the liquid with which it has been covered. The column 

 then subsides, and the liquid of the original drop is seen to pass into 

 the well-known vortex ring which descends through the liquid. 



The influence of velocity of impact in modifying the phenomenon 

 is shown by the drawings. 



When the drop is large, and the fall considerable, the rim thrown 

 up takes the form of a hollow crater- like shell of liquid, the mouth of 

 which closes over the drop, imprisoning air which may remain as a 

 bubble on the surface. This is the bubble seen when large rain drops 

 fall into water. Observations of the bursting of this bubble confirm 

 incidentally the explanation lately given by J. Plateau of the manner 

 of bursting of a soap bubble. 



The splash of a milk drop in petroleum and in olive oil is also 

 described. The course of phenomena is very similar to that in water, 

 modified however by the greater or less mobility of the liquids in 

 question. 



The impact of solid spheres is then described. The nature of the 

 disturbance produced, with a given velocity of impact, is found to 

 depend entirely on the state of the surface of the sphere. 



A polished and perfectly dry sphere of ivory or marble 1 to 3 

 centims. in diameter, let fall from a height not exceeding 1 metre, is 

 apparently wetted at once, and is seen to be sheathed with liquid 

 before the whole is below the average level of the surface. The 

 disturbance of the surface is very slight. 



The same sphere if rough or 2ce£with the liquid in question, behaves 

 quite differently, making a very deep depression, similar at first to 

 that produced by a liquid drop, which finally becomes an almost 

 cylindrical column of air within the liquid, part of which afterwards 

 rises as bubbles while a portion descends in the wake of the sphere. 



