[ ISJ' ] 
V. Impact with a Liquid Surface, Studied hy the Aid of Instantaneous Photography. 
By A. M. Worthington, M.A., F.R.S., Professor of Physics, Royal Naval 
Engineering College, Bevonport, and E. S. Cole, M.A. 
Received September 25, 1895,—Read February 6, 1896. 
[Plates 1-8.] 
Preliminary Statement hy Professor Worthington. 
[n three papers, published in tlie 'Proceedings’''' of the Society, in 1877 and 1882, 
I had the honour to comnuiuicate to the Society the results of experiments on 
various classes of impact with a liquid surface which may all be conveniently referred 
to as "splashes.” The splashes studied were those produced (i.) by a liquid sphere 
falling on a horizontal solid plate, (ii.) by a liquid sphere falling into a liquid, (iii.) by 
a solid sphere falling into a liquid. 
The phenomena were examined by means of an electric flash of very short 
duration, which by a suitable mechanism could be so timed as to illuminate the 
splash at any stage which it wms desired to observe, within three or four thousandths 
of a second. After a sufficient number of repetitions to secure accuracy, a drawing 
was made of the configuration thus revealed, and when one stage had been 
sufficiently studied, the observer passed on to a later sta.ge. Since, however, each 
drawing was made from a separate, though similar splash, it was not possible to 
obtain accurate information about those details which were at once too minute to be 
seized in such single, momentary glimpses, and too unstable to be capable of exact 
reproduction in another splash. 
A photograph, which can be studied at leisure, is under such circumstances 
indefinitely more valuable than a drawing, and produces that confidence in one’s 
knowledge of the facts wuthout which speculation as to the causes can hardly proceed. 
But, at the date when the observations were made, photographic plates, sufficiently 
sensitive to respond to such extremely short exposures were not obtainable, and my 
efforts to secure photographs were unsuccessful. A year and a half ago, encouraged 
by Professor Boys’s success in the photography of flying bullets, I returned to the 
attempt, being also so fortunate as to obtain the co-oj^eration of my colleague at 
* ‘ Proc. Roy. Soc.,’ 1877, vol. 25, pp. 261 and 498, and 1882, vol. 84, p. 217. 
MDCCCXCVII.—A, T 
3,5,97 
