ANNIVERSARY ADDRESS. 23 
gravel; in fact, the heaviest rain now only makes a little stream 
3 or 4 feet wide and a few inches deep. The greater level of the lake 
in that long past period is not difficult to understand when looking 
at the evidence of tropical rains which the gullies afford. At the 
same time, the obvious insignificance of the present rainfall as com- 
pared with that which formed the deltas and filled up the lake, and 
the enormous duration of the present order and condition of things, 
as proved by the discoveries in the European lakes, show how 
groundless were the fears gravely expressed in 1871 that the lake 
would rise up and cover Bungendore and Collector. The rainfall 
on the lake in 1870 was 50 inches, double the average rainfall, 
which is 25 inches, and it is not to be wondered at that the lake 
rose at an unusual rate. Still this rain, heavy as it was, only 
served to cut little gutters in the older deposits which had been 
brought down the gullies. 
The primary object in placing the recording gauge on Lake 
George was to ascertain the rate of evaporation from such a large 
body of water, the conditions at the lake being very favourable 
for such an investigation. The record began on February 18, and 
the time since is too short to justify any assumption of the rate 
of evaporation there; but I may mention some of the facts that 
have been recorded bearing upon this question. In sixty-eight 
days the level of the lake has fallen 7 inches by evaporation ; in 
this interval, according to the records of rain-gauges at each 
end of the lake, 3:55 inches of rain has fallen ; so that ignoring 
the water which may have run from the hills during these rains, 
the lake has lost all the rain falling into it and 7 inches more, 
that is 10} inches. During the past fourteen years the lake has 
lost by evaporation 12 feet ; and in May, 1878, the railway survey 
carried down the western side showed that the lake was then 6 
feet below its 1871 level, or 2,225 feet above the sea. It appears 
therefore, that in seven years, 1871 to 1878, the lake lost 6 feet, 
and again, from May, 1878, to February, 1885, say seven years, the 
lake again lost 6 feet. by evaporation, and this of course in addition 
to all the rain which fell during that period, Taking the records 
