SEICHES AND OTHER OSCILLATIONS 
63 
alongside of the simultaneous seiche on Loch Tay — which was the most 
regular one found on that lake between 4th October and 9th November 
1905. The second pair is the end of the long seiche on Loch Earn 
with the simultaneous one on Loch Tay, whose irregularity is typical. 
As yet our knowledge of the seiches and meteorological conditions 
of Loch Tay is not sufficient to enable us to explain this difference, 
but it may be pointed out here that Loch Tay is relatively a shallower 
lake than Loch Earn, it is more crooked, and the relation of its axial 
line to the path of the minor atmospheric disturbances is different. 
This divergence of conditions occurs in an exaggerated form in 
the case of Loch Lubnaig, which is very shallow, has a very irregular 
basin, and lies across the path of the atmospheric disturbances. 
Accordingly, only four cases were found in which a definite seiche 
could be recognised in Loch Liubnaig, having a period of about 24 
min., and in each case only a few undulations could be counted. One 
of these seiches is shown in fig. 22. During the rest of the six 
Fig. 22. 
weeks of observations nothing was found but wind embroidery and 
sub-permanent wind denivellation, such as would be naturally expected 
in a shallow lake. About this negative result there seems to be little 
room for doubt, as the indications of the converted Sarasin limno- 
graph were controlled by occasional observations with the much more 
delicate index limnograph. 
For our disappointment in Lochs Tay and Lubnaig we find 
consolation in the beautiful seiche behaviour of Loch Earn, which we 
regard as a small but elegant daughter of the Lake of Geneva, the 
great mother of seiches. 
Origin of Seiches 
Forel and his followers, Du Boys, Von Cholnoky, and others, have 
discussed the causes of seiches ; and recently Endros, in his important 
memoir on the Chiemsee, has confirmed the conclusions of his prede- 
cessors, and added some fresh details of great interest. In what follows 
we shall not advance anything of great novelty, but there are two points 
of interest that may be worthy of the reader's notice. In the first 
place, the use of the Dines-Shaw microbarograph enabled us during 
