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XXXII. HYDRAULIC ASPECT OF THE ARTESIAN PROBLEM. 
what can be well utilised, ought to be partially shut down, 
so as to reinforce other bores, and to conserve the supply. 
2. Danger of passing to the sub-artesian condition.— 
In some artesian areas in the United States, the success of 
artesian irrigation and the economic value of the intense 
culture that followed, led to such a multiplication of bores, 
that the supply at last became sub-artesian in many of the 
bores giving previously a spendid discharge. 
And here it may be pointed out that the question of 
whether the condition in the artesian strata is hydraulic 
or hydrostatic, stands out in clear relief. If hydrostatic, 
then the question resolves itself practically into an inquiry 
into two elements only, viz. :— ; 
(1) The total intake per unit of time, say per year, 
(2) The reaction of each bore on neighbouring bores. 
If however, the water in the stratum is flowing, then the 
solution of the whole problem adds another element, viz.:— 
(3) The disposition of bores which gives the largest, 
and best distributed yield. 
If the rate of artesian flow is exhausting the supply faster 
than it is made good by the sources of supply, a diminution 
of flow (or pressure) will inevitably reveal the fact. The 
form of the curve of diminution, as*it may be called, will 
give some Clue to the ultimate consequences of the flow, 
and will have local characteristics. We shall later return 
to the point. 
When the efflux falls to zero, the sub-artesian condition 
has been reached, and the water can be made available only 
by pumping. 
3. Economic effect thereof.—After this condition, viz., 
that of ordinary wells, has been reached, though still pos- 
sible to draw on the supply, the economic aspect of the 
question is considerably changed. It has been found from 
practical experience, that culture which pays when the 
