ON THE HYDRODYNAMICAL THEORY OF SEICHES, 623 
maeA0.: .., E/@=16'4.... As a binodal seiche of 34 in amplitude has been 
observed, maximum horizontal displacements of about 12 feet and stream velocities of 
about 5 feet per minute may occur near the end of the loch; these would be reduced 
in the ratio of °57:1 at the two nodes of the seiche. As the centre of the loch is a 
ventral segment, the horizontal displacement vanishes there at all times, and the 
value of C is half its value at the ends of the loch. © 
TRINODAL SEICHE. 
C,= 0.4 ; T, = 7l/,/(129h) . 
C(c, , w) = 1 — 6w? + 5wt, 
=(1 =w?)(1 — 5w?) . 
C'(c,, wv) = — 12w+ 20w?, 
= (a2 5a) sin n,(t — 7) , 
A 5, ; 
C= al 12a%x — 20x) sin v(t — 7) . 
Three nodes :—a=0, and e/a=+V73/./5=+°7746 .... 
Four ventral points :—a#/a = +°4472, +1. 
= 93) J12= 5 /6= 4082 a0; 
QUADRINODAL  SEICHE. 
= 4.5; T, = l/ /(20gh) . 
S(c,, w)=w— ae + ys : 
= (dw — 10w? + 7w’) , 
1 5 5 
Sal — w*)(3 — Tw?) ; 
Sci.) (3 — 30w? + 351*) . 
B 5 ses 
E= hai (34 — 7x?) sin n,(t —7) ; 
B 4 22 4) gi 
C=—(- 3a + 30a7x? — 354) sin n,(t— 7) . 
Four nodes :—a/a = +°3400 , +°8621 . 
Five ventral points :—a2/a=0, +°6546, +1. 
T/T, = J10 = "3162. 
TRANS. ROY. SOC. EDIN., VOL, XLI, PART III. (NO. 25). 92 
