Sensitiveness of the Ear to Pitch, 



603 



not until an octave higher, in accordance with Wien's 

 conclusions. 









Fig 



2 < 























/ 

















/ 

















I 

























































c 



jT 









1 















• 



J024- 



512 



256 



128 



85 



I take this opportunity of recording a few observation-, 

 on the mode of vibration of these cans, although the results 

 have no immediate connexion with the main subject of this 

 note. The theory of the vibration of thin cylindrical shells 

 vibrating without extension of the middle surface * indicates 

 two distinct types, of which one is excluded by the action of 

 the plane disk forming the bottom of a can. the remaining 

 type is defined by the equations 



Br=sz sin s<f>. a 8<j>=z cos s<f>, 8z=—s~ l a sin s<j>, . (1) 



in which z is measured upwards from the bottom, and the 

 angle $ is measured round the circumference, the radius 

 being a. Br. aB<f>, and Bz are the radial, circumferential, and 

 axial displacements of the point whose equilibrium position 

 is defined by a, <£, z. When - = 0, i. e. at the junction of the 

 cylindrical and plane parts, Br and aBcf> vanish, but Bz 



* Proceedings Royal Society, xlv. p. 105. 1888 ■ Scientific Papers, iii. 

 p. 217. 



