1014 Wisconsin Academy of Sciences, Arts, and Letters. 
two days, is so great that it must be difficult to find considerable 
movements which are not interfered with by the changes of 
weather and it is correspondingly difficult to eliminate the pos¬ 
sible effects of wind. Still further, the fact that even in 
August the epilimnion may practically disappear, as it did on 
Aug. 16, adds to the difficulties of analysis of observations. 
A smaller lake of similar shape with an oscillation period of a 
few hours and with a much warmer epilimnion would offer far 
better opportunities for settling the question of the presence of 
temperature seiches, of their magnitude, if present, and of 
their importance in the temperature changes of the hypolim- 
nion. Loch Ness, of course, lias an advantage over a smaller 
lake in possessing a hypolimnion of enormous mass, so great 
that the loading due to the epilimnion may well be inadequate 
to damp the temperature seiches, if such are started. 
If I may hazard a doubtful opinion, I would say that 
I believe that such seiches may be found to exist. I believe 
also that in most lakes they will be of small extent and of small 
influence upon the temperature. Great and rapid changes of 
temperature in the hypolimnion are due mainly to definite move¬ 
ments of its water, directly caused by the shifting of the 
epilimnion under the action of the wind. Minor changes and 
the slow rise of temperature in the hypolimnion seem to be 
caused chiefly by the irregular currents which result from the 
major movements and which may persist long after their direct 
cause has disappeared. 
Literature Referred To. 
Watson ’04: Movements of the Waters of Loch Ness, as in¬ 
dicated by Temperature Observations. E. R. Watson. 
Geog. Jour., xxiv: pp. 430-437; Figs. 1-3. London, 
1904. 
Wedderburn ? 07: The Temperature of the Freshwater Lochs 
of Scotland, with special reference to Loch Ness. With 
Appendix containing Observations made in Loch Ness 
by Members of the Scottish Lake Survey. E. M. Wed¬ 
derburn. i Trans. Roy. Soc . Edinb., xlv, pt. ii: pp. 407- 
489; Figs. 1-15. Edinburgh, 1907. 
