144 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
3. —No additional 'pumping station, or apparatus would be 
required , at least for the present necessities of the town ; for 
so long as the water levels were kept lower at Northampton 
than elsewhere, so long would the water chiefly flow to this 
place. 
4. —No artificial filter beds would be required. With surface 
water, such as that obtained from running streams, or from 
impounding reservoirs, large filter beds have to be constructed 
and maintained in good condition ; the initial expense is 
considerable, and there is a continuous one afterwards for 
cleaning. Of the three filters, through which it has been 
proposed to pass the water used in filling up the Marlstone, 
viz., the Kiver gravel, Dumb-well, and Marlstone rock, only 
the well would necessitate expense in construction, and this 
would require little or no attention afterwards, for well 
clarified water only would reach it from the river gravel or 
drains. 
5. —The expense of constructing the dumb-ivells would then 
be the chief item. Within the area spoken of as suitable for 
the construction of such wells, none of them would exceed 
140 feet in order to reach the lower water-bearing bed, and 
some of them would be less than this depth. From advice 
obtained, I do not think the wells themselves would cost 
more than £250 each, on an average. The highest figure 
that has been suggested by anybody for them is £1,000. 
I will accept this latter as the cost of them, not that I believe 
it possible they might cost this amount, but because it gives 
a good margin for certain contingencies or further develop¬ 
ments, such as making drains to the wells in certain cases, 
making a communication with the river, or driving a 
heading to join the two water-bearing beds in case a well 
should be made on the wrong side of the Nen “ fault,” &c. 
It might be advisable at the outset to carry a heading 
from the Billing Koad well right up to the “ fault,” 
which could scarcely be more than 500 yards away, and then 
make it communicate with the higher water-bearing bed on 
the southern side of the “ fault.” Such a heading would 
aid very much the draining of the Marlstone, constitute in 
itself a considerable reservoir, and open up a communication 
with the southern Middle Lias area, which, so far, has yielded 
us no water. Of course, the supply from the southern area 
would not be large, because only the lower water-bearing bed 
comes into the town, but it would be a continuous and useful 
addition, and the amount would rather increase than diminish 
with use of the bed, as it has in the case of Messrs. Phipps 
and Co.’s well. 
