| 2 0·003 sec. |
| 3 0·015 sec. | 4 0·037 sec. |
With pure glycerine, which is much more viscous, the splash of the same polished serpentine sphere falling from 75 cm. (about 2-1/2 feet), is shown in Series XIV. In the original photographs the radial furrows on the right-hand side of Fig. 2 are very pronounced, and even in Fig. 1 the fluting of the film is seen to be already well developed on the left-hand side; but these details have proved rather too delicate for reproduction in the plate. Two photographs taken of stage 2 had each of them an isolated jet, owing probably to the fact that when working with so sticky a liquid it was difficult to avoid contaminating the cloth on which the sphere was each time repolished after washing in water, with the result that the spheres behaved as if locally rough. The relatively great length and height of this jet brings out well the part played by viscosity, both in delaying segmentation into droplets and also in hindering the flow of the rest of the liquid sheath which has remained in contact with the sphere.
With a rough sphere falling into pure glycerine from the same height of 75 cm., except for an occasional jet that may escape as in Fig. 4 of Series XV, the proceedings are uneventful, as a glance at the series will show. With the same height of fall into water we should have had an exquisite crater fringed with a multitude of fine jets, and ultimately closing to form a bubble. We thus see how little play is given to the action of the surface-tension in a very viscous liquid.
| Polished stone sphere falling 15 centim. into water mixed with glycerine. SERIES XIV Polished stone sphere falling 75 centim. into pure glycerine. Scale 9/10. 1 2 3 |
SERIES XV
Rough sphere falling 75 centim. into
pure glycerine. Scale 1/1.
1 T = 0 2 0·001 sec. 3 0·002 sec. 4 0·003 sec. |
| 1 | |
| 2 | |
| 3 | |
| 1 T = 0 | |
| 2 0·001 sec. | |
| 3 0·002 sec. | |
| 4 0·003 sec. |
THE INFLUENCE OF TEMPERATURE.
It was found that if a polished sphere was heated in boiling water, quickly rubbed dry, and let fall while still hot, a very marked difference was produced. With the sphere hot, the height of fall can be much increased before the splash becomes "rough." Thus with paraffin oil, the height with a nickel-plated sphere rose from 22·2 cm. to 29·3 cm., and with water from 157 cm. to 234 cm.
THE REMARKABLE INFLUENCE OF A FLAME HELD NEAR THE LIQUID, AND TRAVERSED BY THE SPHERE IN ITS FALL.