122 Transactions.— Miscellaneous. 
organic forms, chiefly of a low type of animal life, are found also. The 
most careful artificial filtering fails to free the water entirely from these 
organisms, some of which are now regarded as the probable source of many 
diseases. Filtering certainly fails to eliminate the germs; that is to say, 
such artificial filtering as is possible on a large scale, such as that of a 
water supply. But what art cannot do, nature does with unerring certainty, 
for microscopic examination shows that the water from deep strata is per- 
fectly free from every form of organic life. It must be remembered also 
that the vast. natural filter-beds which lie between Invercargill and the 
Hokonuis do their work without trouble or interference, and while perfect 
in their action, are not a source of expense. I therefore claim for the 
subterranean supply the double advantage of abundant quantity and perfect 
purity. 
The quantity and purity being taken for granted, it has still been 
objected to this proposal that the expense of pumping, and the difficulty of 
obtaining a sufficient pressure for extinguishing fires, render it inferior to a 
gravitation scheme. Without now going into details, I may remark that 
the question of expense is one which can easily be settled by calculation ; 
and I fearlessly assert that the expense of pumping will be but a mere 
fraction of the interest on cost and the maintenance of thirty miles of 
iron mains. 
It should be noticed that the pumping scheme has the advantage of being 
capable of expansion, at no great expense, exactly as the wants of the town 
increase. When one shaft is no longer sufficient, another at a small 
distance can be added, and the supply doubled, and so on as required. Or 
should it ultimately be decided to adopt a gravitation scheme, this would 
not stand in the way; for, with the single exception of the pumping 
machinery and shaft, everything else in the town service is exactly the 
same as that required for the gravitation scheme, and could be utilized 
without the slightest loss or additional expense. 
On all these grounds it appears that the subterranean sources of supply 
are worthy not only of more attention than has hitherto been bestowed 
upon them, but of a serious practical trial. The expense of a trial-shaft 
would not exceed £200, including hire of engine and pumps. The question 
of quantity would then be for ever settled. 
