Vibration Curves of Violin Bridge and Strings. 457 



2. Each of the strings gives considerable motion to the 

 bridge in spite of the presence of* the other three strings which 

 are not sounding, whereas previously only the Gr-string 

 gave appreciable motion to the part of the belly under 

 examination. 



3. The distribution of the bridge's motion seems to be 

 somewhat intricate. Thus a certain corner of the bridge 

 w T ould scarcely stir in one direction under the influence 

 of a given string excited in a certain manner, but went 

 extremely well under the influence of another string or 

 the same string excited differently. These circumstances 

 may be due to the asymmetry of the stresses and structure 

 of the violin. 



4. In some cases the motion of the bridge lengthwise of 

 the string shows a frequency double that of the string, 

 although such a phenomenon had not been detected by the 

 previous work on the belly. 



This point has some interest in connexion with the w r ork of 

 Mr. J. W. Giltav and Prof. M. de Haas * of Delft. 



Experimental Arrangements. 



The mounting of the violin was all through as in fig. 2 of 

 Plate iv., Phil. Mag. Aug. 1909. The optical arrangements 

 were also on the same general lines as before, so that the 

 string's motion is recorded in the positive print by a dark 

 line on a light ground, the motion of the bridge being- 

 recorded below it by a white line on the dark ground. It 

 should be noted here also that great steadiness of the arc 

 light was obtained by the use of a Leitz Lilliput arc lamp in 

 which the positive carbon is horizontal. The plates used 

 throughout were the Barnet Orthochromatic, Fast, Backed, 

 and were developed by the Barnet formula. 



Vertical Motions of the Bridge. — For the vertical motions 

 of the E-string corner of the bridge the arrangements were 

 almost precisely those shown in figs. 1-5, Plate iv. of the 

 last paper (Phil. Mag. Aug. 1909), the only essential 

 modification being that the leg of the optical lever m rested 

 on the bridge instead of on the belly. 



For the vertical motions of the G-string corner the 

 arrangements were of the same nature, but the other side 

 of the violin was turned towards the lamp and plate. 



* " On the Motion of the Bridge of the Violin," Konink. Akad. v. 

 Wetenschappen, Amsterdam, Proc. xii. pp. 513-524, Jan. 26, 1910. 

 Also Science Abstracts, No. 404, Mar. 1910. 



