1894.] on the Splash of a Drop and Allied Phenomena. 299 



any rate up to a height of fall of 4 or 5 feet, depends entirely on the 

 state of the surface of the sphere. A polished sphere of marble about 

 0*6 of an inch in diameter, rubbed very dry with a cloth just before- 

 hand and dropped from a hsight of 2 feet into water, gave the figures 

 of Series VI., in which it is seen that the water spreads over the 

 sphere so rapidly, that it is sheathed with the liquid even before it 

 has passed below the general level of the surface. The splash is 

 insignificantly small and of very short duration. If the drying and 

 polishing be not so perfect, the configurations of Series VII. are pro- 

 duced ; while if the sphere be roughened with sand-paper, or left wet, 

 Series VIII. is obtained, in which it will be perceived that, as was the 

 case with a liquid drop, the water is driven away laterally, forming 

 the ribbed basket-shaped hollow, which, however, is now prolonged to 

 a great depth, the drop being followed by a cone of air, while the 

 water seems to find great difficulty in wetting the surface completely. 

 Part of this column of air was carried down at least 16 inches, and 

 then only detached when the sphere struck the bottom of the vessel. 



Figs. 6 and 7 show the crater falling in, but this did not always 

 happen, for the walls often closed over the hollow exactly as in 

 Figs. 4 and 5 of Series IV. Meanwhile the long and nearly cylin- 

 drical portion below breaks up into bubbles which rise quickly to 

 the surface. 



By increasing the fall to 5 feet we obtain the figures of Series IX. 

 The tube of Fig. 1 corresponds to the dome of Series IV. and V., and 

 is not only elevated to a surprising height, but is also in the act of 

 cleaving (the outline being approximately that of the unduloid of 

 M. Plateau). Figs. 2 and 3 show the bubble formed by the closing 

 up of this tube, weighed down in the centre as in Figs. 5 and 6 of 

 Series V. Similar results were obtained with other liquids, such as 

 petroleum and alcohol. 



Tt is easy to show in a very striking manner the paramount influ- 

 ence of the condition of the solid surface. I have here a number of 

 similar marbles; this set has been well polished by rubbing with 

 wash leather. I drop them one by one through a space of about 

 1 foot into this deep, wide, cylindrical glass vessel, lighted up by a 

 lamp placed behind it. You see each marble enters noiselessly and 

 with hardly a visible trace of splash. Now I pick them out and 

 drop them in again Tor to save trouble, I drop in these other wet 

 ones), everything is changed. You see how the air is carried to 

 the very bottom of the vessel, and you hear the " (/>Aotcr/?os " of the 

 bubbles as they rise to the surface and burst. These dry but rough 

 marbles behave in much the same way. 



Such are the main features of the Natural History of Splashes, as 

 I made it out between thirteen and eighteen years ago. Before passing 

 on to the photographs that I have since obtained, I desire to add a few 

 words of comment. I have not till now alluded to any imperfections 

 in the timing apparatus. But no apparatus of the kind can be ab- 

 solutely perfect, and as a matter of fact, when everything is adjusted 



