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Curupertson.—On a Water Supply for Invercargill. | 121 
Arr. XIII.—On a Source of Water Supply for Invercargill. 
By Joun R. Ouruzerrson. 
[Read before the Southland Institute, 4th May, 1881.] 
ABSTRACT. } 
Ir seems certain that the whole of the country between Invercargill and the 
Hokonuis consists of a comparatively level deposit of silts and clays, resting 
on a bed of sandstone sloping gently to the south. This deposit of gravel, 
ete., lying on the impervious subjacent rock, has been proved by actual 
experiment to be absolutely saturated with water ; and that, as soon as we 
pass the first bed of clay, at a very considerable pressure indeed. Here 
then is what we want ; an inexhaustible supply of well-filtered water, close 
at hand. Why go thirty miles for what can be had within less than thirty 
yards ? Supposing for a moment that artesian springs will never be dis- 
covered strong enough to reach the surface, and that even the supply from 
@ series of tube wells might not prove sufficient, why not sink an ordinary 
shaft, protected by suitable casing (say a bridge cylinder), as far as such a 
shaft could be sunk, and kept dry with a good pump and a ten horse-power 
engine ? When the engine can no longer keep down the water, then you 
have got all you want, namely, a water supply which will suffice for many 
& year to come, and that at a very moderate cost. From what I have seen 
I should be much surprised if such a shaft ever reached the depth of 100 
feet, the quantity of water is so great. Then as to the permanence of the 
supply. There seems no reason to suppose that the vast subterranean 
stream which it is proposed to tap should be less permanent than any river 
flowing on the surface. Of the existence of this immense supply of water, 
all who witnessed the progress of the borings are firmly convinced; and it 
Seems reasonable that others should accept their testimony. The water 
Was in fact the one difficulty, and an ever-present difficulty, in the way of 
the boring. A recent bore put down at Clinton to a depth of 102 feet, pre- 
Sented precisely the same features, so far as the constant inrush of water 
Was concerned. There is really no question as to the quantity. Then as 
to quality: the water from all the lower levels tasted perfectly pure and free 
from any mineral solution. As to its freedom from organic matter, twenty 
miles of natural gravel filter, from the base of the Hokonuis to Invercargill, 
‘8 @ sufficient guarantee for that. This is an advantage which no water 
