76 
(2 _— ie *) : for the latter quantity is the displacement of the 
membrane due to the cylinder with the small membrane A 
removed, or which is the same thing, the original cylinder pushed 
1 
back a distance a 
Thus the displacement through A due to unit pressure on the 
original membrane = ie ae 
Thus displ: Bie eas 16 BOD! ace to’ iabh 
wus displacement at A = 72, —7—. due to unit pressure on 
membrane. 
Hence displacement at A in the direction 7 due to pressure 
42~C on membrane = Ee aS 
47 dz 
Further, if P is the pressure at A this displacement 
=e Sb? ace 
da dx 
. P= CO constant, 
In this analogy P, of course, corresponds to magnetomotive 
force. 
7 al 
a See 
