128 THE FKESH-WATER LOCHS OF SCOTLAND 
The effect of all this is to increase the period of the seiche ; and in 
Loch Ness the gradual lengthening of the period was detected. Thus, 
while in August the period was about three days, in November it was 
found to be between five and six days. 
~i /,? 15 zi z3 / 3 5 y 9 // o IS // '9 -2,1 23 / 3 s Y~7/ Ul^ 
Fig. 50. 
Observations of extreme interest were made by Dr Felix M, Exner 
in the Wolfgangsee in July and August 1907. He worked with six 
electrical resistance thermometers, which were immersed at the follow- 
ing depths : — 
Thermometer No. . I. H. III. IV. V. VI. 
Feet. . . .2-1 62 13-4 23-8 40-0 69'3 
