[Illustration: FIG. 96.--Separating rice grains by flailing.]
[Illustration: FIG. 97.--The principle of the lever.]
152. The Lever. Balance a foot rule, containing a hole at its middle
point _F_, as shown in Figure 97. If now a weight of 1 pound is
suspended from the bar at some point, say 12, the balance is
disturbed, and the bar swings about the point _F_ as a center. The
balance can be regained by suspending an equivalent weight at the
opposite end of the bar, or by applying a 2-pound weight at a point 3
inches to the left of _F_. In the latter case a force of 1 pound
actually balances a force of 2 pounds, but the 1-pound weight is twice
as far from the point of suspension as is the 2-pound weight. The
small weight makes up in distance what it lacks in magnitude.
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