80 On Irrigation in Tasmania , 
up by an embankment 14 feet high, and very solid, with 
a sluice-gate in it, in about a fortnight, and at an expense 
of about £70. The Lagoon contains about 1000 acres, 
and, by means of the above-mentioned embankment, can 
hold about 15,000,000 cubic yards of water, which, 
allowing for evaporation, would leave 13,000,000 for use y 
or sufficient for 6500 acres throughout the summer, or 
20,000 if irrigated only till harvest; being at a cost of 
3d. per acre for grass land, and 1 d. per acre for grain. 
At the head of the Jordan there is a far more extensive 
lagoon, which might be shut up at the same cost, or 
thereabouts. But, of all rivers in the Island which I 
have seen, the Lake is that which offers the finest field 
for improvement by irrigation, having three large lakes 
at its head, and flowing through a country containing 
hundreds of thousands of acres fit for the plough, and in 
the finest climate for grain in the Island. Were these 
lakes embanked at their outlet, large canals might be led 
off on each side of the Lake River soon after it leaves 
the hill country, directly through the country, command¬ 
ing a tract 10 or 12 miles in breadth, and conveying a 
supply of excellent water through all the towns and 
villages with which such a country must eventually be 
covered, and probably at no distant period. Two or three 
hundred pounds expended upon closing the outlets of » 
these lakes, and more probably much less, would secure 
water enough for 200,000 acres; and the cutting of the 
main canals from the Lake River upon a very extensive 
scale, would not probably cost at the rate of more than 
10s. per acre of land watered. 
Having thus considered the singular preparation there 
is in the Colony for extensive irrigation, the effects of it 
should next be examined. 
There appear to be four main points in which the' 
advantages of irrigation would be felt in the Island :— 
