ANNIVERSARY ADDRESS. 19 
the water in rising and falling, and its “period” as the time it 
takes to complete the motion. Their amplitude is very variable, 
but at the same place and on the same day they are all alike: 
when large all are large, and when small all are small. Sometimes, 
as on August 3, 1763, they have been measured 4 feet 10 inches 
rise and fall; and on 2nd and 3rd October, 1841, some were 
measured 6 feet 7 inches, They are greater at the ends of the 
ake than in the middle, and the period varies very much with the 
size of the lake ; but in the Lake of Geneva, which is 45 miles 
longand 2 —_ the longer ones ee of seventy-two minutes, 
and tl f thirty inutes. Dr. Forel, whohas studied 
those of the Lake of Geneva, very carefully attributes the ordinary 
seiches to local variations of atmospheric pressure, giving an im- 
pulse, the effect of which lasts a long time in the oscillations of 
the lake; but those of from 4 to 5 feet he attributed at one time 
to earthquake shocks, but now thinks they are due to violent gusts 
of wind, for at least one earthquake passed the lake without pro- 
ducing such motions. Mr, Plantamour, who was watching at the 
end of the lake, while Dr. Forel was in the middle, said, after long 
and careful study he was quite at a loss for an explanation of 
these curious motions. 
Some of the surroundings of Lake George are of very great in- 
terest, viewed in the light of discussions as to the possible change 
in the amount of rainfall in the Colony during long periods; and 
although I cannot now stay to discuss them at length, I cannot 
pass them without a short reference to their bearing on the ques- 
tion. The lake itself is situated in a depression between two 
ranges of hills, some of which, on the western side, rise to 800 
feet above the lake. On the eastern side the hills generally stand 
some little distance from the water, but on the western side, at 
least in a part of it, the hills seem to rise abruptly out of the water 
at an angle of from 30° to 45°, The hills are composed of hard 
metamorphic rocks, the fragments of which are carried down into 
the lake by every shower, and are very soon polished into gravel 
by the action of the waves; and the enormous deposits of gravel at 
