705 
1910-11.] Meetings of the Society. 
The reigns of Your Majesty’s August Predecessors were characterised by remarkable progress 
in the various branches of human knowledge and activity ; and we are confident that under Your 
Majesty’s Rule still greater advance will be witnessed in all that makes for the welfare of the 
British Empire and of the many Races that own Your sway. 
We would also express our cordial welcome to Her Most Gracious Majesty, Queen Mary; 
and would place on record our humble and earnest prayer that Your Majesties may long be spared 
to rule over a prosperous and contented people. 
(Signed by the President and General Secretary.) 
PRIZE. 
The Council having awarded — 
The Makdougall-Brisbane Prize for the biennial period 1908-09, 1909-10 to Ernest 
Maclagan Wedderburn, M.A., LL. B., for his series of papers bearing upon the Temperature 
Distribution in Fresh-water Lochs, and upon Seiche Phenomena which occur at the interface of 
two layers of different density, whether that difference be due to difference of temperature or 
difference of salinity, published in the Proceedings of the Society within the prescribed period, 
and also in the Transactions and Proceedings before and after that period : — this Prize was 
presented. 
On Presenting the above prize the Chairman read the following statement : — 
Having been appointed physicist to the Scottish Lake Survey under the direction of Sir John 
Murray and Mr Laurence Pullar, Mr E. M. Wedderburn, first in association with Mr E. R. 
Watson, and subsequently by himself, investigated the temperature distribution in Loch Ness in 
a more thorough manner than had ever before been attempted in a fresh-water loch. The results 
are published in the Transactions of the Society (vol. xlv. ). The presence of a “ sprungschicht, ” 
or layer through which the temperature of the lake changes at a rapid rate with depth, had 
already been recognised as occurring at certain periods of the year and at depths which varied 
with each lake and with the meteorological conditions of each year. By his observations at Loch 
Ness, Mr Wedderburn established the existence of a temperature or density seiche which occurred 
at this layer of rapid change of temperature, and showed that the period of the seiche could be 
roughly calculated for Loch Ness by means of an approximate formula. The temperature seiche 
had been discussed by Mr E. R. Watson in 1904 ; and ten years earlier by Professor Thoulet of 
Nancy ; but the latter did not pursue the speculations which he had made. 
In the same paper Mr Wedderburn also discussed the effect of winds on the temperature 
distribution in lakes, an effect which had generally been disregarded by limnologists, although 
Sir John Murray had called attention to it. As a verification of the theory and a demonstration 
of the fact of a temperature seiche, experiments were made in a long glass tank containing two 
liquids of different density. Over the surface of the upper and lighter liquid a current of wind 
from a rotary fan was blown, with a consequent production of a seiche at the interface of the two 
liquids. Thus it was shown that winds are a vera causa in the production of the temperature 
seiche ; and fresh light was thrown upon the whole question of the influence of wind upon lake 
temperatures. See Proceedings of the Society, vol. xxviii. 
Following up these researches along a new line, Mr Wedderburn demonstrated for the first 
time by direct observation the existence of a return current in deep water, which compensated for 
the surface current due to the action of the wind. The depth at which this return took place 
was shown to depend on the temperature distribution for the time being. 
Analogies between the temperature seiche and long-period oscillations observed in the 
sea were also suggested, from which it appears probable that temperature observations in lakes 
may be of importance in solving oceanographical problems. 
Doubt having been expressed by limnologists in Germany and the United States as to the true 
nature of the temperature seiche, Mr Wedderburn arranged an expedition, jointly with Professor 
Halbfass, to study the temperature distribution in the Madiisee, Pomerania. The observations 
and conclusions, which are given in a paper published in the Transactions of the Society (vol. xlvii. ), 
have proved to the satisfaction of Mr Wedderburn’s critics that a temperature seiche exists in 
fresh-water lakes whenever the layer of rapid temperature change is well marked. By an extension 
of the method employed by Professor Chrystal in his discussion of ordinary seiche phenomena, 
Mr Wedderburn in this latest paper gives a mathematical discussion of the temperature seiche, 
and deduces a hydrodynamical theory applicable to lakes of variable depth and breadth. The 
theory, which gives a close numerical accord with the data of observation, was also tested by 
experiments in tanks of various shape. So close is the analogy between the temperature seiche 
and the ordinary seiche that the period of the one may be calculated from the period of the other. 
For this interesting and important series of investigations into problems closely connected with 
the phenomena of the temperature seiche in fresh-water lakes, a large part of which was carried 
out and published during the biennial period 1908-9, 1909-10, the Council of the Royal Society 
of Edinburgh have awarded the Makdougall-Brisbane Prize. 
The following resolution, submitted by Dr R. Kidston, was carried unanimously: “That 
from the beginning of next Session onward, all the Ordinary Meetings of the Society be 
vol. xxxi. 45 
