﻿Vibration Curves for Strings and Air of Violin, 891 



Further, it is seen in each figure that after the plate was 

 released the velocity was accelerated, and accordingly the 

 wave-length of the record increases from left to right. 



In the case of bowing and some of the other excitations 

 of the string it will be seen that the spot suffers no large 

 sudden displacement at the commencement of the vibrations 

 (see figs. 34, 35, 38, 40, 42, 46, 53, 59). 



But often with plucking there is a sudden shift of the 

 spot at the instant of the excitation (see figs* 37, 44, 45, 

 49, 50, 51, 55). This shiit is probably due to the yield of the 

 violin, as a whole, under the deflecting action of the finger 

 holding the string up before the release. On the release, 

 the violin, regarded as a deflected beam, then springs back. 

 Further, the violin sometimes vibrated as a whole after the 

 shock of this release or under a blow struck. For a 

 comparatively long wave of these slow vibrations is shown 

 on figs, 37, 41, 43, 44, 50, 51, 52, 60, 61. 



Fig. 58 shows first a slow vibration rapidly damped out, 

 succeeded by a longer wave vibration on which are super- 

 posed the motions corresponding to the musical vibrations 

 proper to the E-string. 



As to the duration of the slow vibration of the spot shown 

 as a long upward half-wave near the centre in figs. 44, 50, 

 and 51, the time is found to be of the order of one-fortieth 

 of a second, corresponding to a frequency of twenty per 

 second. This time is estimated by counting the corre- 

 sponding vibrations of the string shown on the upper part 

 of the plate. The strings were always tuned to concert 

 pitch and so had approximately the following frequencies : — 

 G, 203-4 ; D, 305-1 ; A, 457'7; E, 686'5. 



All the figures 34-61, taken by this special method of 

 shooting, explain why it was impossible to obtain by the 

 other method any large amplitude of the spot's motion by 

 plucking or striking. For, as now shown, the spot's 

 amplitude in the musical vibration corresponding to the 

 pitch of the string is always small, with this belly mounting 

 of the mirror. The large motion of the spot (often observed 

 to occur on a fixed screen put in place of the plate) is dow 

 seen to be dne simply to the sudden shift of the violin as a 

 deflected beam on the release when plucking or on receiving 

 the blow when striking. 



University College, Nottingham, 

 January 26th, 1912. 



