1905-6.] The Hydrodynamical Theory of Seiches. 
149 
h 
1 
T a 
obs. 
calc. 
obs. 
calc. 
10-5 
1-42 
1-43 
•78 
•78 
11 
1-50 
1-49 
•81 
•81 
11*4 
1-52 
1-51 
•84 
•83 
11-8 
1 '55 
1-54 
oo 
05 
•84 
6. Seiches in a concave truncated quartic lake [§ 52]. 
A r Q O a A 
[? = <?] 
h(x) = h(a 2 — x 2 ) 2 
[h = log" 1 7-55594. d = 12] 
l 
T x 
1 
'2 
T 3 | 
1 
t 5 
T 6 
Tv 
d 
r 
obs. 
calc. 
obs. 
calc. 
obs. | 
calcJ 
obs. 
calc. 
obs. 
calc. 
obs. 
calc. 
obs. 
calc. 
12 
70 
8 
1-3 
1-328 
•74 
•688 
•56 
•464 
12 
84 
5-6 
1-52 
1-62 
•88 
•85 
•67 
•57 
•54 
•43 
•48 
•34 
■44 
•29 
•39 
•25 
12 
102 
3-5 
2-02 
2-02 
1*13 
1-102 
•80 
•748 
It will he noticed in the results for the seiches of high 
nodality of the concave parabola and quartic curve that the 
divergence between theoretical and observed results increases 
with the nodality. The rapidity of the oscillations* and the 
corresponding difficulty of observation does not altogether account 
for this ; but it must be remembered that the theoretical investi- 
gation presupposes that the square of the ratio of the depth to 
the wave length is negligible. This was by no means the case in 
the experiments carried out. In the case of the uninodal seiche 
of Loch Earn, for example, this quantity is j-gVo- In the experi- 
ments discussed here its value varied from ~ to \ for seiches of 
high nodality. 
