1907.] 



on Seiches in the Lakes of Scotland. 



661 



recorder at Lochearnhead wnich lasted for 6 days llf hours. 

 It is what we shall presently define as a dicrote seiche. Although 

 insignificant as to range, compared with Plantamour's example, 

 it is, so far as I know, the next best in point of duration yet 

 observed. 



The next example is a seiche on the Sea of Galilee.* The range is 

 magnified to about If of the natural size, and an hour occupies about 

 lof in. It is the most recent limnogram in my possession, having 

 l)een taken by Mr. E. AV. G-. Masterman, on March 26 last, in 

 the course of an investigation into the seiches of the lakes of 

 Palestine. 



The next set of examples (see Fig. 4) are from Loch Earn, all 

 taken by the waggon recorder near St. Fiilans. The two upper 

 curves are very smooth, and furnish excellent examples of what we 







to Jt »•> It 



Fig. 4. 



call the configuration period of a dicrote seiche. No. 3 is an example 

 of the strongly-marked embroidery which appears on the limnogram 

 during stormy weather. Xo. 4 is an example of a seiche in moder- 

 ately calm weather broken by varying weather conditions. Xo. 5, 

 except for the slight wind embroidery, gives an example of an almost 

 pure sinusoidal curve. It was taken near one of the points on the 

 lake, which we shall presently define as binodes, and furnishes a test 

 of the mathematical theory. 



Causes of Denivellation. — Let us now consider the various causes 

 which may affect the level of a lake. AVe may enumerate the 

 following : — 



1. Volume Denivellations. — Caused by precipitation or evapora- 



Eshibited in the Lecture Room and in the Library of the Institution, 



