OUR LAKES AND THEIR USES. 147 
25 feet. Mr. Russell, the Government Astronomer, in his notes on 
the climate of New South Wales, describes it as the largest and 
most important of the fresh water lakes of the Colony, fed by a num- 
ber of creeks from a watershed of about 1,200 square miles ;*he 
asserts that its water was brackish, but drinkable, except in 
seasons, and he estimates the evaporation as equal to 2 feet in wet 
sa, and from 7 to § feet in dry seasons. In his Presidential 
Address before this Society last year, however, he modifies his pre- 
vious views considerably, both as regards the freshness of the water, 
and the effects of evaporation, and takes exception to the proposals 
to use the lake .as a reservoir for the supply of towns. He then 
regarded the water as unfit for use, on account of its purgative 
properties, and added that it was reported that the drainage from the 
Currowang Copper Mine had poisoned all the fish. This mine is 
from its underground workings into the pump well was so im- 
pregnated with copper, that it completely coated a sheet of iron 
and some tools which had been left in it for a time. The baling 
of this water into a creek connected with the lake, must have con- 
taminated the water in the immediate vicinit , but is certainl 
not a sufficient cause to account for the death of fish miles away 
from the locality. Im any case if this mine is ever worked again, 
a repetition of the mischief can easily be prevented, by distributing 
the well water over the adjacent hills. As regards the brackishness 
of the water, it must be patent to anyone who studies the con- 
dition of the lake, that, owing to its shallow depth round three 
water. Even when the lake itself is fast drying up, oe 
and cattle drink and thrive on its water, whilst as it recedes, it 
leaves a nourishing pasturage of wild parsnip, and ~—— succulent 
cane grass, which uk of all kind devour with a This 
proves that its water possesses valuable properties heesunio for 
the nourishment of vegetation, and therefore admirably fitted for 
irrigation. In his address, Mr. Russell doubts whether any large 
quantity of water could be withdrawn, because “ during 64 years 
for by far the greater number of. years, the supply of rain water 
has not been equal to the evaporation.” On re reflecting on all the 
conditions connected with the fall of water in the lake, I am led 
