the Sounds of Splashes. 147 



tiny fragment of silvered mirror cemented to the needle as 

 shown in (/■>). 



m. 



Fig. 1 in the Plate shows the record obtained when a 

 highly polished steel sphere 2 cm. diameter was allowed to 

 fall 100 cm. on to the surface of water. The record is a 

 straight line, showing that the splash was soundless. Figs. 2 

 and 3 were obtained with the same sphere and height of fall, 

 when the surface of the steel was dimmed with a touch of 

 grease. The two records are closely similar, and show that 

 sounds were produced at two different stages of the splash 

 with an interval of distinct silence separating them. An 

 interesting contrast with figs. 1, 2, and 3 is furnished by 

 fig. 4, which is the record of the sound of a " basket" splash 

 produced by the fall of a steel sphere of the same diameter 

 through the same height, the difference being that in the 

 present case the surface of the steel sphere had been 

 roughened by allowing it to rust. It will be noticed that 

 there is a stage at which there is a violent disturbance, this 

 being due to the characteristic sound of the " basket" splash. 

 Figs. 5 and 6 are also records of the sounds of "basket" 

 splashes produced by the fall of wooden spheres 10 cm. 

 diameter from a height of 100 cm. The striking difference 

 between the intensity of the sounds indicated by the records 

 in the two cases was due to a slight difference in the condition 

 of the surfaces of the two spheres. 



The authors hope, when a suitable opportunity arises, to 

 continue the study of the sounds of splashes of which the 

 preliminary results are contained in the present note. 



Calcutta. 8th July, 1919. 



L2 



