When, as in the last figure of Series VI, p. 85, we saw the upward-directed jet, then also there must have been an equal and opposite generation of downward momentum distributed in some way through the liquid below the basin, of which, however, there could be no visible sign. Hence we see that the present downward jet is, in a sense, not a new phenomenon, but one which, having existed unnoticed before, is now rendered visible to us by reason of its being produced in air instead of in water. By means of a hole bored through the ceiling of the dark room, the fall was then increased to 281 centim. (just over 9 feet). The very beautiful earlier stages of the splash at this height are shown in Series XVIII. Fig. 4 shows very well the internal splashing at the top of the air-column which accompanies the initiation of the jet. Some later photographs taken at this height (not yet quite presentable) show the jet passing right down the narrow neck of air-tube and probably striking the top of the sphere, the descent of which must thus be liable to a curious irregularity. A further increase of the height of fall to 686 centim. (22-1/2 feet) was found to produce but little change in the phenomena. [Illustration: SERIES XVIII Early stages of the splash of a rough sphere (diam. 1·5 centim.) falling 281 centim. (about 9 feet) into water. 1 T = 0 2 0·003 sec. 3 0·005 sec. 4] FOOTNOTES: [K] I can recommend any reader who is not afraid of being late for breakfast to keep a bag of marbles in his bath-room. PRINTED BY WILLIAM BRENDON AND SON, LTD PLYMOUTH [Transcriber's Note: The following changes have been made to the original text. Page 10: "the same in 1, 3 and 4" changed to "the same in 1, 2 and 4" Page 66: "·04 of a gram" changed to "0·4 of a gram" Page 77: Added full stop to image caption 9 "0·042 sec." End of Project Gutenberg's A Study of Splashes, by Arthur Mason Worthington