OF ARTS AND SCIENCES. 



221 



but differing largely from the last series, though we may notice that 

 Fig. 9 resembles Fig. 5. 



These two series of curves show conclusively that the arrangement 

 of the curves is not materially altered by a change in the ellipticity 

 when the plate is bowed at the edge, but that the curvature of the 

 curves does correspond very closely to the change in the ellipticity of 

 the plate. Furthermore, that the nearer the plate comes to a straight 

 bar, the more the figures in the two series resemble each other ; show- 



Fig. 7. 



Fig. G. 



Fig. 8. 



ing that the nearer the plate is to a circle, the more various are the 

 figures obtained by damping and bowing in different places. 



I also tried to obtain a series of similar curves by exciting the vibra- 

 tions through a hole bored in the centre of the plate. But in this I 

 failed ; I could get a set of curves for two or three consecutive plates, 

 but not throughout the whole set of plates. One fact which was par- 

 ticularly noticeable in connection with this set of experiments was, that 

 five or six sets of curves resulted from bowing the same plate in appar- 

 ently exactly the same way, although the plate gave a different note 

 for each set of curves. 



