The wheel lies, with its two gudgeons
or center pins, upon two brasses, fixed on
two great levers, whose fulcrum or top, is
an arched piece of timber, the levers be-
ing made circular on their lower sides to
an arch, and kept in their places by two
arching studs, fixed with a sock through
two mortices in the lever.

By these levers the wheel is thus made
to rise and fall with the tide: the levers
are sixteen feet long, that is, from the ful-
crum to the gudgeon of the water wheel
six feet, and thence to the arch ten feet.
To the bottom of this arch is fixed a strong
triple chain, made like a watch chain,
but the links are arched to a circle of one
foot diameter, having notches or teeth to
take hold of the leaves of a pinion of cast
iron, ten inches diameter, with eight teeth
in it, moving on an axis.  The other loose
end of this chain has a large weight hang-
ing at it, to help to counterpoise the
wheel, and to preserve the chain from
sliding on the pinion.  On the same axis
is fixed a cog-wheel, six feet in diameter,

By means of this machine, the strength
of an ordinary man will raise about fifty
tons weight.  But, besides these levers
and wheels, there is a cog-wheel eight
feet diameter, fixed near the end of the
great axis, and working into a trundle of
four feet and a half diameter, and twenty
rounds; whose axis or spindle is of cast
iron, four inches diameter, and lying in
brass at each end: a quadruple crank of
cast iron, six inches square, each of the
necks being turned one foot from the cen-
ter, which is fixed in brass at each end,
in two head-stocks fastened down by caps.
The end of one of these cranks is placed
close abutting to the end of the axle-tree
last mentioned, and fixed thereunto by an
iron wedge drove through a slit in them
both for that purpose.  The four necks of
the crank have each an iron spear or rod
fixed at their upper ends to the respective
lever, within three feet of the end; which
levers are twenty-four feet long, moving