Seiches in Some Lakes of Japan. 63 



Putting 10^— J— 71 — ^-nßi in these equations, we get the 

 Vghi <^i 



displacements for the point G ; they are 



^=^C{hJ,(nß,) + /x{Y,(nß,)]sin n(t-T) ) 



m 



:='^^{hJo{nß^) + r.{Y,inß,)]sm n{t-T) ) 



Proceeding in precisely the same way from the other end of the 

 lake, and equating the values of ^ and Ç. at C, we must have 



Eliminating A^' and A^\ we get the equation for the period, 

 which is 



a,ß,h, [hJMi)-\-!hY,{nß,)}[kUnß.;) + lJt.^,{nß.^} ^ç^ , . 



Solving this equation for n gives us the period 



T=-^. (6) 



The positions of nodes corresponding to this period will be found by 

 putting C=0 in (1) or (3) or the similar equations for the segments 

 CD and DE, according as we are looking for nodes in the segments 

 AB, BG or GD, DE. 



To apply this result to the case of Hakone, we must proceed 

 as Chrystal and AVedderburn did in the case of Lochs Treig and 



