478 Dr. J. Robinson on Konufs Theory of the 



The sound-wave travels along the tube. He lets 



2^ 1 = v l = u 2 = v 2 z=:0j and w 1 = w 2 , 



and so finds the potential of the forces between two small 

 spheres inside the tube to be 



n=-7rTl/E 2 V 



3-D 3.. .2 V 



2 ' 



d 



if the density of the fluid be taken as unity. Now letting w 

 vary periodically with the time as it does in the Kundt tube, 

 according- to the law 





Vl also varies with the time. 



Konig finds the mean value of Vt to be 



y 1 



Q= _^W COB' 2^* 



t <V.o r 



-j I cos- 2ir- 

 lc Jo t 



.,1 



— JB^V 







2 ~l~*~o g 



The components of the force between the spheres are 

 immediately found. 

 Thus 



d«i' 



Deduction of the 1 heory on Different Grounds. 



The theory can be obtained also in the following way: — 

 In the Kundt tube experiment the sound-waves travel 

 parallel to the axis of the tube. Then if we put 



m 1 =v 1 =w 2 = v 2 =0, and Wi = w 2 



in KirchhofFs general equal ions, we get for the kinetic energy, 



