From John Whitehurst
Printed in the Royal Society, Philosophical Transactions..., LXV
(1775), pp. 277-9.
[Before March 16, 1775.]
Dear Sir,
Presuming the mode of raising water by its momentum may be
new and useful to many individuals, induces me to send you the
inclosed plan and description of a work, executed in the year
1772, at Oulton, in Cheshire, the seat of Philip Egerton, Esq.
for the service of a brewhouse and other offices, and is found to
answer effectually. I am, Sir, Your most obedient servant,
Please to observe, that the circumstances attending this waterwork,
require a particular attention, and are as follows (see
Tab. vii, fig. A.): (A) represents the spring or original reservoir,
whose upper surface coincides with the horizontal line BC, and
the bottom of the reservoir K. D the main pipe, 1½ inch diameter,
and nearly two hundred yards in length. E a branch pipe, of the
former dimensions, for the service of the kitchen offices. Now it is
to be observed, that the kitchen offices are situated at least eighteen
or twenty feet below the surface of the reservoir A, and that the
cock F is about sixteen feet below it. G represents a valve-box, g
the valve, H an air-vessel, oo the ends of the main-pipe inserted
into H, and bending downwards, to prevent the air from being
driven out when the water is forced into it, w the surface of the
water. Now it is well known, that water discharged from an
aperture, under a pressure of sixteen feet perpendicular height,
moves at the rate of thirty-two feet in a second of time; therefore
such will be the velocity of the water from the cock F. And
although the aperture of the cock F is not equal to the diameter
of the pipe D, yet the velocity of the water contained in it will be
very considerable: consequently, when a column of water, two
hundred yards in length, is thus put into motion, and suddenly
stopped by the cock F, its momentous force will open the valve g,
and condense the air in H, as often as water is drawn from F. In
what degree the air is thus condensed, is needless to say in the
instance before us; therefore I shall only observe, that it was
sufficiently condensed to force out the water into the reservoir K,
and even to burst the vessel H, in a few months after it was first
constructed, though apparently very firm, being made of sheet
lead, about nine or ten pounds weight to a square foot. From
whence it seems reasonable to infer, that the momentous force is
much superior to the simple pressure of the column IK; and therefore
equal to a greater resistance (if required) than a pressure of
four or five feet, perpendicular height. It seems necessary further
to observe, that the consumption of water in the kitchen offices
is very considerable; that is, that water is frequently drawing
from morning till night all the days of the year.
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