If the present volume is so fortunate as to find many readers among the general public, as the author hopes it may, especially among the young whose eyes are still quick to observe, and whose minds are eager, it will be on account of admiration for the exquisite beauty of some of the forms assumed, of surprise at the revelation of so much where so little was expected, and because of the peculiar fascination that is always felt in following any gradually changing natural phenomenon, in which the sequence of events can, partly at any rate, be anticipated and understood. For the sake of serious students of Physics who may be interested in unexpected phenomena of fluid motion, all references that seem necessary have been given in footnotes, and it may be mentioned that the later photographs of Series I and those of Series I-a and III, have not been previously published, and afford new information on certain points. In taking these photographs the author has been much helped by his friends Dr. G. B. Bryan and Mr. G. F. Page. A. M. W. TAVISTOCK, _Sept. 18, 1907_. [Added _March 1, 1908_.] A slight delay in the publication of this book has afforded the opportunity of obtaining the new and quite unexpected information given in the supplementary chapter. CONTENTS PAGE CHAPTER I PRELIMINARY--METHODS OF OBSERVATION AND APPARATUS 1 CHAPTER II THE SPLASH OF A DROP--LOW FALL 15 CHAPTER III PRINCIPLES INVOLVED 32 CHAPTER IV THE SPLASH CONTINUED 41 CHAPTER V HIGHER FALLS--BUBBLE-BUILDING 53 CHAPTER VI BELOW THE SURFACE 69 CHAPTER VII THE TWO KINDS OF SPLASHES OF SOLID SPHERES 73 CHAPTER VIII THE TRANSITION FROM THE SMOOTH OR "SHEATH" SPLASH TO THE ROUGH OR "BASKET" SPLASH 95 CHAPTER IX THE EXPLANATION OF THE CAUSE OF DIFFERENCE BETWEEN THE TWO SPLASHES 108 CHAPTER X CONCLUSION 118 CHAPTER XI (SUPPLEMENTARY) A NEW PHENOMENON THAT APPEARS WITH AN INCREASE IN THE VELOCITY OF ENTRY OF A ROUGH SPHERE 121 FOOTNOTES: [A] "Impact with a Liquid Surface," by Worthington and Cole. _Phil. Trans. Roy. Soc._, A 193, 1897, and A 255, 1900. [B] _Pearson's Magazine_, July and August, 1898. A STUDY OF SPLASHES CHAPTER I PRELIMINARY--METHODS OF OBSERVATION AND APPARATUS