ON IMPACT WITH A LIQUID SURFACK. 181 



With the polished sphere hot, the height of fall can be much increased before the 

 splash Incomes " rough." Thus, with paraffin oil, the height with a nickelled sphere 

 rose from 22'2 centims. to 2D'.'{ centims., and with water from 157 centims. to 

 234 centims. 



[njliiencc of Flame held near the Liquid, and (rare run I by tie Sphere in 



it* Fall. 



It then occurred to us to let the sphere drop through a Hume held near the liquid, 

 and the result was very remarkable. With paraffin oil (and the sphere hot) the 

 airless height now rose from 29'3 centims. to 45'3 centims., and with water and a cold 

 sphere, it rose from 157 centims. to over 258 centims., which was the greatest height 

 that the lalx>ratory would permit. Either the luminous flame of a bat's wing burner 

 or the flame of a Bunsen burner held nearly horizontal produces the effect, provided 

 the flame is held near enough to the surface of the liquid, and it is a very striking 

 experiment to let the polished sphere fall several times from a height which gives a 

 large volume of hubbies rising with much noise to the surface, and then to let it fall 

 through the flame, and to observe the complete change in the phenomenon. 



Electrification. 



It seemed to us extremely probable that we had here to deal with an electrical 

 phenomenon, for a flame would certainly discharge completely any electrified sphere 

 passing through it, and it appeared reasonable to suppose that the sphere became 

 electrified by friction when falling through the air. Experiments were therefore 

 made to test this supposition. Holding the flame high above the surface should 

 diminish the effect, for the sphere would become again electrified in the remainder of 

 its fall. Experiment abundantly confirmed this view. Thus, with the maximum 

 height of fall available (258 centims.), the flame was still quite effective at 68 centims. 

 above the surface of flowing water, but quite ineffective at 113'5 centims. 



Nevertheless, other tests failed to confirm this theory of electrification. If the 

 difference is due to electrification, we argued, then it ought to become very 

 conspicuous when the sphere is deliberately electrified. Accordingly, a long series of 

 experiments was made, in which the sphere soon after its release came into contact 

 with a flexible wire brush connected to a Wimshurst machine, and thus was electrified 

 positively or negatively at pleasure. A height of fall was then chosen for which the 

 splash was either just airless or just not airless when the sphere was unelectrified, so 

 that the influence of electrification in changing the character of the splash either way 

 could be observed. 



The results of these observations were curiously discordant,* and though it is 



* The probable reason will be mentioned later. 



