14 ANNIVERSARY ADDRESS. 
This stage is 6 feet square, and on the top of it a small iron 
house, 6 feet x 5 feet, was put up to cover the recording gauge. 
A hole was then cut through the floor, and the iron well for the 
float let down. This is 18 inches in diameter, and is bolted to 
the floor, and by cross-bracing to the posts below. In the bottom 
of it, six holes, an inch in diameter, were made; these allow the 
water to go in and out with sufficient freedom to show ordinary 
waves without knocking the float about. The house is built at 
the end of the jetty in front of Douglas House, and is 60 feet 
from the shore, the water at that distance from the edge being 
only 4 feet deep. 
The work of erecting the instrument was completed on the 
afternoon of February 18th, and the pencil was put down on the 
paper to begin its curious record at 7 p.m. on that day. At the 
time the lake seemed calm as a millpond, and looking at its 
smooth surface no one would have dreamed that such changes 
were going on in it as began to reveal themselves so soon as the 
pencil touched the paper, and in two hours the pencil had re- 
corded arise and fall of about 2 inches. This is not a motion 
like the ordinary wind-made waves, which pass by in two or 
three seconds, but a slow and gradual rise, occupying an hour, 
and then a corresponding fall in about the same time, to do which 
a current must first have set from north to south for an 
hour, and then reversed; and if we consider for a moment the 
force necessary to put a body of water 18 miles long, 5 wide, and 
15 or 20 feet deep, in such motion, we shall get some idea of the 
magnitude of the forces at work. The record had not been going 
twenty-four hours when it became obvious that these periodic 
motions in the level of the water had a period of about two hours ; 
and on the afternoon of the second day a heavy thunder-storm 
passed over the south end of the lake, and threw a little light on 
the cause of the pulsations. The storm rain was very heavy, and 
much of it must have run into the lake, tending to raise the 
waters there. With the storm there came a violent squall of 
wind from the south, on to the south end of the lake; in a few 
