1910-11.] 
The Temperature Seiche. 
257 
XII. — The Temperature Seiche. Part I. Temperature Observations 
in the Madiisee, Pomerania. Part II. Hydrodynamical Theory 
of Temperature Oscillations in Lakes. Part III. Calculation 
of the Period of the Temperature Seiche in the Madiisee. 
By E. M. Wedderburn, W.S. Part IV. Experimental Verifica- 
tion of the Hydrodynamical Theory of Temperature Oscilla- 
tions. By E. M. Wedderburn, W.S., and A. M. Williams, M.A., 
B.Sc. 
(MS. received December 23, 19] 0. Read December 5, 1910.) 
[Abstract] 
This paper is published at length in the Transactions of the Society, 
vol. xlvii., part iv., p. 619, and describes observations in the Madiisee, Pomer- 
ania, made by Professor Halbfass and Mr Wedderburn, with the view of 
testing the latter’s theory of temperature seiches in lakes, arrived at from 
a consideration of the observations of the Scottish Lake Survey. 
Part I. 
During the three weeks from 25th July to 14th August 1910, about 
3000 temperature observations were made in the Madiisee, and oscillations 
with a period of from 24'4 hours to 2 5 3 hours were observed during most 
of the time. Observations were made at each end of the lake and at the 
centre. The phase of the oscillations was opposite at the two ends of the 
lake, and the amplitude was very small at the centre of the lake, indicating 
the proximity of a node. 
During the period of observation the temperature discontinuity or 
Sprung schicht was very abrupt. 
Part II. 
An approximation to the actual conditions in a lake is got by supposing 
that to a depth h' the density of the water is uniformly p, and thereafter 
uniformly p. On this assumption, and taking the origin in the surface of 
separation (i.e. at depth h'), it is found that the temperature oscillations in 
lakes depend on the equation : 
d?P 
dv 2 
- P = 0. 
g%(v)(p-p) 
VOL. XXXI. 
17 
