| 150 | L O N | |
on centers in a frame, at the end of which
are jointed four rods, with their forcing-
plugs, working into four iron cylinders,
cast four feet three quarters long, seven
inches bore above, and nine below, where
the valves lie, fastened by screwed flanches
over the four holes of a hollow trunk of
cast iron, having four valves in it, just at
the joining-on at the bottom of the barrels
or cylinders, and at one end a sucking
pipe or grate, going into the water, which
supplies all the four cylinders alternately.
From the lower part of these cylinders
come out necks, turning upwards arch-
wise, whose upper parts are cast with
flanches to screw up to a trunk; which
necks have bores of seven inches diameter,
and holes in the trunk above, communi-
cating with each of them; at which join-
ing are placed four valves. This trunk is
cast with four bosses, or protuberances,
standing out against the valves, to give
room for their opening and shutting; and
on the upper side are four holes stopped
with plugs, which take out, on occasion,
to cleanse the valves. One end of the
trunk is stopped by a plug; and iron pipes
are joined by flanches to the other end,
thro' which the water is forced up to any
height or place required.
Besides these four forcers, there are four
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more placed at the other ends of the le-
vers, which work in the same manner, with
rods and cylinders, as above. And the
same works are repeated at the other end
of the water-wheel, viz. a cog-wheel, a
trundle, a spindle, a crank, sucking-pipes,
four levers, eight forcing-rods, eight cy-
linders, &c. four trunks, and two forcing-
pipes: so that one single wheel works six-
teen pumps.
In the first arch next the city, is one
wheel with double work of sixteen forcers.
In the third arch, where the first wheel
has double work at the one end, and sin-
gle at the other, there are twelve forcers:
the second wheel, placed in the middle,
has eight forcers; and the third wheel
sixteen forcers. In all fifty-two forcers.
One turn of the four wheels makes 114
strokes; and when the river is at best, the
wheels go six times round in a minute,
and but four and a half at middle water;
so that the number of strokes in a minute
are 684; and as the stroke is two feet and
a half in a seven inch bore, which raises
three ale gallons, they raise 2052 gallons
in a minute; that is, 123,120 gallons, or
1954 hogsheads in an hour, which is at
the rate of 46,896 hogsheads per day, to
the height of 120 feet, including the
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