THE ROMANCE OF SCIENCE
THE SPLASH OF A DROP
BY
Prof. A.M. WORTHINGTON, M.A., F.R.S.
Being the reprint of a Discourse delivered at the Royal Institution
of Great Britain, May 18, 1894.
PUBLISHED UNDER THE DIRECTION OF THE GENERAL
LITERATURE COMMITTEE.
LONDON:
SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE,
NORTHUMBERLAND AVENUE, CHARING CROSS, W.C.;
43, QUEEN VICTORIA STREET, E.C.
Brighton: 129, NORTH STREET.
New York: E. & J.B. YOUNG & CO.
1895.
THE SPLASH OF A DROP
INSTANTANEOUS PHOTOGRAPHS OF THE SPLASH OF A WATER-DROP FALLING ABOUT 16INCHES INTO MILK.
Time after contact = ·0262 sec.
Time after contact = ·0391 sec.
Time after contact = ·101 sec.THE SPLASH OF A DROP
The splash of a drop is a transaction which is accomplished in thetwinkling of an eye, and it may seem to some that a man who proposes todiscourse on the matter for an hour must have lost all sense ofproportion. If that opinion exists, I hope this evening to be able toremove it, and to convince you that we have to deal with an exquisitelyregulated phenomenon, and one which very happily illustrates some of thefundamental properties of fluids. It may be mentioned also that therecent researches of Lenard in Germany and J.J. Thomson at Cambridge, onthe curious development of electrical charges that accompanies certainkinds of splashes, have invested with a new interest any examination ofthe mechanics of the phenomenon. It is to the mechanical and not to theelectrical side of the question that I shall call your attention thisevening.
The first well-directed and deliberate observations on the subject thatI am acquainted with were made by a school-boy at Rugby some twentyyears ago, and were reported by him to the Rugby Natural HistorySociety. He had observed that the marks of accidental splashes ofink-drops that had fallen on some smoked glasses with which he wasexperimenting, presented an appearance not easy to account for. Drops ofthe same size falling from the same height had made always the samekind of mark, which, when carefully examined with a lens, showed thatthe smoke had been swept away in a system of minute concentric rings andfine striæ. Specimens of such patterns, obtained by letting drops ofmercury, alcohol, and water fall on to smoked glass, are thrown on the