208 Scientific Proceedings, Royal Dublin Society. 



argued), they should be detected by means of suitably -tuned 

 resonators — and, in a few cases, they can be — but more often than 

 not, they are largely subjective. 



I hope to perform some further experiments in connection with 

 this subject shortly. 



So far we have been considering the effects of sound upon 

 jets of moderate diameter. Let us now see what happens when 

 the jet is narrower. 



If a jet of water about one millimetre in diameter is projected 

 almost vertically, it breaks up, and scatters into fine spray soon 

 after leaving the orifice. When a rather high-pitched tuning-fork 

 is sounded and placed on the supporting stand, the scattering is 

 prevented ; and the stream, which now presents a beautifully 

 wavy appearance, remains entire, until almost its highest point is 

 reached. 



If we photograph such a jet falling normally, we can see, as in 

 the former cases, that it consists of small and large drops alternating, 

 irregularly spaced, and of various shapes. The appearance of the 

 same jet when influenced by a tuning-fork is quite different. 

 (Plate XXII., fig. 1.) The drops formed are all about the same 

 size, very regular in their outline, and practically equidistant. 

 Fine streams may often be seen shooting out at the sides, 

 particularly if the note be impure. 



The effect of a tuning-fork of high pitch on a very fine jet, 

 projected upwards at a moderate angle, is very curious. The 

 stream frequently divides into two, three, or more streams, quite 

 distinct from each other. These streams revolve round one 

 another, making it difficult to secure a satisfactory photograph. 

 Plate XXII., fig. 3, shows the phenomenon well. There is a 

 central stream of drops larger than those constituting the others ; 

 but all are arranged in perfect order, the drops in each stream 

 being equidistant from their fellows. Plate XXII., fig. 2, shows 

 the same jet uninfluenced by sound. 



From the foregoing experiments, therefore, we see that the 

 general effect of musical sound upon liquid jets is to make them 

 regular and uniform ; and this is rendered evident to the eye by 

 their symmetry of form, and to the ear by the notes they 

 produce. 



