584 Proceedings of the Royal Society of Edinburgh. 
[Sess. 
PROCEEDINGS OF THE ORDINARY MEETINGS, 
Session 1909-1910, 
The First Special Meeting of the Royal Society for the Session 1909-1910 was held in the 
Freemason’s Hall, where Sir Wm. Turner, The President, delivered his Inaugural Address on 
Monday, 8th November 1909, at 8 o’clock. 
After the Address a Reception was held at No. 24 George Street. 
FIRST ORDINARY MEETING. 
Monday , 22nd November 1909. 
Sir William Turner, President, in the Chair. 
The following Prizes were awarded and presented : — 
1. The Makdougall-Brisbane Prize for the biennial period 1906-08 to D. T. Gwynne- 
Yaughan, M.A., F.L.S., for his papers (1st) “On the Fossil Osmundaceae,” and (2nd) “ On the 
Origin of the adaxially-curved Leaf-trace in the Filicales,” communicated by him conjointly with 
Dr R. Kidston. 
Professor Gwynne- Vaughan holds a leading place among the plant-anatomists of the present 
time. This position is based, not only on the very fine series of memoirs on the fossil Osmundaceae 
which have been presented to this Society, but also upon earlier work. He successfully investigated 
the polystelic condition in the stems of the Primulaceae and the abnormalities in the Nymphseacese ; 
but the papers which have probably contributed most to his high reputation are the two on 
Solenostelic Ferns, published in the Annals of Botany. The effect of these has been to show how 
along phyletic lines the complicated condition seen in the cyatheaceous and polypodiaceous stems 
came into existence and to reduce these to terms of a clear theory of dictyostely. 
He is an anatomist who has already achieved much and from whom much may still be 
expected. 
2. The Gunning Victoria Jubilee Prize for the third quadrennial period 1904-08 to Professor 
George Chrystal, M.A., LL. D., for “A series of papers on ‘Seiches,’ including ‘The Hydro- 
dynamical Theory and Experimental Investigations of the Seiche Phenomena of certain Scottish 
Lakes.’ ” 
Professor Chrystal ’s attention was drawn to the subject of Seiches by the work of Sir John 
Murray and his staff in the Survey of the Scottish Fresh- water Lakes. It was known that a seiche 
was a standing oscillation of a lake usually in the direction of its greatest length, but the periods 
and positions of the nodes of the harmonic components of the oscillation could only be calculated 
mathematically for the simple case of a lake of uniform depth. Professor Chrystal discovered 
what would have seemed prior to its discovery a very difficult problem, a mathematical treatment 
applicable to lakes of variable depth. The hydrodynamical theory which he established gives a 
close numerical accordance with the facts of observation. 
The theory was compared with observations on Loch Ness, Loch Treig, Loch Tay, and 
especially on Loch Earn. In the course of these observations Professor Chrystal modified the 
sarasin limnograph, making it more sensitive for seiches of small amplitude, and also devised a 
new instrument, the stato-limnograph, in which a Richard barograph is adapted to measure very 
small fluctuations of level occurring in short periods of one minute or less. 
These instruments present the rhythmical rise and fall of the level of a lake as a continuous 
curve. In some cases these curves are complicated and their analysis into the sum of a number of 
simple oscillations is a matter of difficulty. Professor Chrystal devised the method of “ residua- 
tion ” which is applicable to all numerical data in which regular but unknown variations are 
hidden. 
Professor Chrystal has also considered the conditions under which seiches are formed and 
seiches of long duration maintained. Among other causes, seiches on Loch Earn are traced to the 
fall of rain on part of the lake and to abrupt changes of the barometer. It is also established that 
seiches of long duration are closely associated with barometric fluctuations of a quasi-periodic 
character. 
By a combination of mathematical and experimental skill, Professor Chrystal has completely 
solved the kinematical problem of the Seiches of Loch Earn, and his investigations may well serve 
as a model for the examination of the seiches of other lakes. In addition he has made important 
advances in discovering the relationship between seiches and the attendant meteorological 
conditions. 
