628 PROFESSOR CHRYSTAL 
UnINoDAL AND BINODAL SS#ICHES. 
§ 38. Since, as has already been mentioned, y=2°77 . . . . and ¢=12°384 78 
if T, and Y, be the periods of the uninodal and binodal seiches respectively, we have 
bu! 
S/S = (2 0 a Bay Aa 
The distances of the binodes from the centre of the lake are given approximately by 
v/a=°472. 
SEICHES IN A CONCAVE ASYMMETRIC BIPARABOLIC LAKE. 
Fic. 6, 
§ 39. Let the equations for the portions O A and A’O be A(x) =h x (1 —@3/a’) ; and 
h(x) =hx(1—2a"/a”). Then, if w=a/a, w’ =a/a’; c=n’a*/gh, c' =n’a"/gh, we have for 
the two portions 
En(1 — w®) = {A C(c, vw) + B S(c, w)} sin nt, 
C =- HA C'(e, w) + BSc, w)} sin nt}; 
and 
E(1 — w?) = {A Cle, w') + BY Sc’, w') }sin nt, 
@ = — 1 {A C(¢') +B Se, w')}sin nt 
> a 
The boundary conditions at A and A’ give 
AC(c, 1) Bic, D0 
AY Ce, 1) B See 1)— 0; 
The conditions =, C=C at O give obviously 
Ae wAC 
B/a=B'/a. 
From these we deduce 
a'C(c,J1)S(e’, 1) + aC(c, 1)S(e, 1)=0, 
‘ ‘ (41) 
a K(c, 1) +aK(e’, 1) =). 
which is the equation that enables us to calculate c or c’, if we remember that 
cfc =a" a", 
