24 ANNIVERSARY ADDRESS. 
at Goulburn and Gungahleen, near the lake, the average rainfall 
for the first seven years was 27-95 inches, and during the next 
seven years 23°68 inches. One would expect to find more evapora- 
tion during the drier years, but this is not borne out by obser- 
vations. From the rainfall and recorded evaporation the lake, 
therefore, lost by evaporation at least 3 feet per annum. I say 
at least, because some rain-water must have run into the lake 
in addition to that which fell into it directly, but its amount 
cannot be determined. In the heavy rains, January 24-5-6, 1885, 
Lake George rose, by measures taken at the jetty, 114 inches, 
and there had been 6} inches rainfall at Bungendore, 94 inches 
at Collector end, and 8 inches at Gundaroo, say 8 inches over 
basin of Lake George. In 1870 about 50 inches rain fell, 
and the lake rose 14 feet—168 inches, «e¢., about 3 to 1, and 
in a recent case it was only 14 to 1, yet this rain fell in 
about forty hours. In future the recording gauge will determine 
this, and perhaps then we may apply the experience gained to 
estimating how much ran in during the past fourteen years. 
That the gauge will serve this purpose is proved by what it has 
already done. On March the 11th a strong northerly wind came 
on, and in three days the lake lost by evaporation 14 inch. On 
April 14 and 15 1°10 inch rain fell, with a strong wind, and by 
the 17th the lake had lost ali the rain by evaporation, and was at 
the same level as on the 13th. On the other hand, in calm or 
almost calm weather, three, and even four days pass without any 
visible loss by evaporation. It should be stated, with regard to 
the rain on 14th and 15th April, that though 1-70 inch fell at 
Douglas, only 0°77 inch fell at the north end of the lake, and 
the rise in the water due to it was 1} inch, so that it would appear 
but little of that rain-water came down the hills into the lake. 
The evaporation on the lake on a windy day shows to what extent 
the wind affects it. No doubt its effect on a large body of water 
is much greater than on a small one, because on the lake in calm 
weather the lower air must get to a certain extent saturated with 
moisture, and there being no wind to carry it away, evaporation 
practically ceases ; but where small quantities of water are placed 
