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in the holes provided for them in the axle, are moved in
a circular direction, and thus cause the ascent of the
weight. Thus also, an iron lever being applied to a
weight which many hands could not remove; if a ful-
crum, which the Greeks call o, be placed under
it, and the tongue of the lever be under the weight, one
man’s strength at the end will raise the weight. This is
accounted for by the fore part of the lever being under
the weight, and at a shorter distance from the fulcrum
or centre of motion; whilst the longest part, which is
from the centre of motion to the head being brought into
circular motion, the application of few hands to it will
raise a great weight. So if the tongue of the lever be
placed under the weight, and instead of the end being
pressed downward it be lifted up, the tongue then hav-
ing the ground for a fulcrum, will act on that as in the
first instance it did on the weight, and the tongue will
press against the side thereof as it did on the fulcrum:
though by this means the weight will not be so easily
raised, yet it may be thus moved. If the tongue of the
lever lying on the fulcrum be placed too far under
the weight, and the end be too near the centre of
pressure, it will be without effect ; so, as hath been
already mentioned, will it be, unless the distance from
the fulcrum to the end of the lever be greater than from
the fulcrum to the tongue thereof. Any one will per-
ceive the application of this principle in the instruments
called steelyards (stateræe) ; for when the handle of sus-
pension, on which as a centre the beam turns, is placed
néarer the end from which the scale hangs, and, on the
other side of the centre, the weight be shifted to the
different divisions on the beam, the further it is from
the centre, the greater will be the load in the scale
which it is capable of raising, and that through the
equilibration of the beam. Thus, a small weight, which,
placed near the centre, would have but a feeble effect,
may in a moment acquire power, and raise with ease à
