470 Mr. G-. W. Walker on the 



.. p(?/i-^2) _„, :; ■ p (yi-y^) -o 



??ii£;i — P ^^^ = ^2^ 2 + P 1 ^J 



where (^P H-^-;/^^ is the pressure between the two particles. 



We thus get 



miti'i + m2i'2 = const.. 

 7?ii2/i + wi22/2 = const., 

 niiZi + 771202 = const. ; 

 so that the motion o£ the c.G. is independent of the waves. 

 For the rotational motion we get 



^ \mi m^J r \7?h 1112) 



\m^ 1112 1 r 



\mi 1112/ r 



where 



OC1 — X2 = ^, Vx-Vi — V, ^1—2^2 = ?, 



and 



Now r is constant. 



Hence . . . _ 



and 



Thus we get 



