‘G. H. KNIBBS. XXVII. 
Il.—THE INDETERMINATION OF THE PROBLEM. 
1. Hydrokinetic elements of the problem.—Hven though 
initially there were no motion of the water in the artesian 
stratum, the flow from the bores has now established one 
and has lowered the original pressure everywhere, by 
amounts which vary not only with the distance from the 
point of efflux, but also with the coarseness of the rock 
and its porosity and with the thickness of the stratum from 
point to point. The ascertainment of the lines of flow 
assist in enabling an estimate to be made as to whether 
the strata are thick or thin, which can also be estimated 
by the phzeenomena of flow, as the number of bores increase. 
The uncertainty as to the details of the facts at great 
depths makes the hydrokinetic elements of the problem 
indefinite and conjectural. 
2. General indetermination of the problem.—This may 
be more fully explained as follows:—If the water in an 
unpierced stratum is quiescent, the pressure would every- 
where be simply the hydrostatic pressure, varying merely 
with the level of the stratum. If however, the water 
therein is flowing, then the pressure depends on the rate 
of flow, falling where the velocity is high, and increasing 
where it is low. Consequently where a body of water is 
flowing through interstitial spaces in a stratum, local 
increase in the thickness thereof, is associated with rise 
of pressure, and local thinness with fall of pressure, because 
in the latter case the potential energy has been changed 
to actual, vice versa in the former. See Fig. 4 hereinafter 
TV. 7, 8. 
Where the pressure at any point in a stratum is greater 
than that due to a head of water, equal in height to the 
distance from the stratum to the surface, an artesian bore 
will certainly flow, but the rate of flow will depend upon: 
(1) The state of the artesian tube, and still more upon 
