624 PROFESSOR CHRYSTAL 
(JUINQUINODAL SEICHE. 
a. 
G9 
bo 
corals T,=7l/ ./(30gh) . 
C(c, , w) = 1 — 15w? + 35t — 21 v8 = (1 — w?)(1 — 140? + 21 2*) 5 
C'(e; , w) = — 30w + 140w? — 1260? . 
E= Se — 14022? + 2124) sin m,(t—7) ; 
Ma 
(=A (30ate — 1400228 + 12625) sin n,(t=7). 
a 
Five nodes :—a=0 , x/a= +£°5384 , +°9062. 
Six ventral points :—w/a = +°2853 , £°7650, +1. 
1 
T,/T, = 7g V15= 2582. 
§ 33. The following conspectus of the numerical distances from the centre of the 
nodes and ventral points will give a clear idea of the shortening of the wave length 
towards the ends of the lake :— 
I, Brnopatu. II. TRInopat. 
aa 4X a/a 4X 
V “0000 ‘DITA N “0000 “4472 
N ‘DTTA "4226 Ww 4472 3274 
V 1:0000 N ‘7746 +2254 
V 1:0000 
III. QuADRINODAL. TV. QUINQUINODAL. 
«e/a +r x/ a 4A 
V “0000 *3400 N “0000 "2853 
N *3400 *3146 Vv "2853 2531 
V 6546 2075 N 5384 2266 
| N "8621 WB) we ‘7650 1412 
| WV 1:0000 | N ‘9062 0938 
V | 1:0000 
It will thus be seen that the wave length near the centre is greater, and near the 
end is less than it would be in a lake of the same length but of uniform depth. All 
the nodes and ventral points which are not central are displaced towards the shallows. 
As we see from § 8 that the amplitudes of the various pure seiches at the end of 
the lake is of special interest, the following table may be given, in which R denotes the 
