Rough sphere falling 140 cm. into water. Scale 2/3.

1
0·006 sec.
2
0·008 sec.
3
0·015 sec.
4
0·021 sec.
5
0·038 sec.

The segmentation of the air column appears to be independent of the jet; but some photographs, such as Fig. 7, show the jet striking the side and breaking into the surrounding liquid with a great accompaniment of "air-dust."

SERIES XVII—(continued)

6
0·043 sec.
7
0·052 sec.

N.B.—Each of these figures is made up from two photographs; one of the upper and one of the lower portion taken from different splashes, but with the same "timing."

The reader will observe that after division of the air-tube has taken place, say from Fig. 9 onwards, the water entering the jet at the top and coming out again at the bottom must circulate as in a vortex ring, part of the core of which is filled with the air surrounding the jet.