October 29, 1908] 



N^ TURli 



66 



/ 



rough sphere into water from a height of 140 centi- 

 metres. Figs. I, 2, 3, 4, and 5 here reproduced are 

 from this series, and they serve well to show the 

 beauty of Prof. Worthingron's results, as also the 

 curious formation of a liquid jet within the temporary 

 bubble. 



Figs. 1 and 2 show the open cup with the vertically 

 projected cylindrical sheet of water and its breaking 

 edge. In Fig. 3 the capillarv tension has pulled in ihe 



realised unintentionally when a leaking tap allowing 

 drops to fall into a vessel full of water is neverthcles-; 

 so disposed that either succeeding drops are not almost 

 exactly alike or the water into which the drops fall 

 has not come perfectly to rest so that a musical note 

 is sounded at each fall, the variations in the tone being 

 surprisingly large and erratic. \ record of the note, 



Fk^ 



sides, and is on the point of completing the bubble. In 

 Fig. 4 the surface of the bubble is being pulled down 

 by'the descent of the ball, which reduces the pressure 

 within the bubble. As there is less mass in the iilm 

 .above than in the continuous liquid sides, the roof 

 is at first drawn downwards. .At this stage it also 

 thickens from an influx of liquid from the sides, or 

 appears to do so, and this influx, meeting in the centre. 



FiG. 2 —0008s. 



if it could be kept audible by acoustically screening 

 ofl' the snap of the spark, and a comparison of this 

 with the alternating periods revealed by the photo- 

 graphs, should, if it were worth while, make clear the 

 source of the musical note and the cause of its varia- 

 tion. 



Fiij. 3.— 0-0I5S. til.. 4-- 0'02IS. 



Rough sphere fa'llng 140 cm. into water. From '■ ^ Study of Splashes. 



FlG. 5. — o'0575. 



gives rise to a powerful descending jet seen in Figs. 5 

 to II of the book. The acceleration is greater than 

 that due to gravity, and it appears that the curved 

 path of the inrushing liquid concave downwards en- 

 ables it to balance the excess of atmospheric pres- 

 sure above the bubble. 



It would be interesting to see a number of photo- 

 graphs of drops falling into water in conditions often 



NO. 2.^35, VOL. 78] 



It is not possible in the space available to illustra'.e 

 or describe more of the results shown in Prof. Worth- 

 ington's interesting book. It is hoped that enough 

 has been said to excite the interest of experimentalists 

 and others, who will be well repaid by a study of 

 the orieinal, which should find a place in every scien- 

 tific library. 



(;. V- Bovs. ■ 



