OF THE MOTIONS OF FLUIDS. 327 



waves : and on the other hand a wave reflected backwards 

 and forwards within a prismatic canal of its own length, 

 abruptly terminated at each end, will exhibit a vibration 

 precisely resembling that of an elastic chord. It may 

 be inferred from the consideration of the motion of a chord 

 so continued, that the point corresponding to the end of 

 the primitive chord will always remain at rest ; whence it 

 follows that the motion of the chord, terminated by such a 

 fixed point, must be the same as if it were continued in the 

 manner described, the reasoning being the same as in the 

 cage of the reflection of a wave. 



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