ne fifth of
the diameter of the other, the smaller will revolve five times for one
revolution of the other.

CRANK.--With a _crank_ two feet long, one may turn a wheel twice as
easily as with one one foot long, but the hand will move twice as far.
If a wedge is two inches thick at the large end and ten inches long, a
man may lift 1000 pounds by striking the wedge a 200-lb. blow.

INCLINED PLANE.--If a plank twelve inches long has one end on the ground
and the other on a cart four inches high, one man can roll up the plank
the same weight that would require three men to lift, but he has to move
the object three times as far.

PROBLEMS

1. Why is a long-handled spade easier to dig with than a short-handled
one?

2. Which is easier, to dig when the spade is thrust full length or half
length into the earth?

3. Can a small boy "teeter" on a board against a big boy? How?

4. In helping to move a wagon, why grasp the wheel near its rim?

5. In making a balance, why should the arms be equal? In a balance with
unequal arms, compare the weights used with the article weighed.

6. In using shears, is it better to place the object you wish to cut
near the handles or near the points?

7. Where is the best place to put the load on a wheel-barrow?

8. Notice how three horses are hitched to a plough or binder.

9. Where would you grasp the pump-handle when you wish to pump (1)
easily, (2) quickly?

10. Stretch out your arm and see whether you can hold as heavy a weight
on your hand as on your elbow.

11. Count the pulleys used in a hay-fork and determine the use of each.

12. If a ton of hay is unloaded at five equal forkfuls, what weight has
the horse to draw at each load?

13. Count the cogs on the wheels of a fanning-mill, washing-machine,
apple-parer, or egg-beater, and determine how the direction or rate of
the motion is changed thereby.

14. Measure the diameter of the large fly-wheel of a thrashing-machine
engine, and of that which turns the cylinder in the separator. Decide
how many times the cylinder revolves for one turn of the fly-wheel.

15. Think of all the uses of a wedge. Draw one. Compare the axe, knife,
and chisel with the wedge.

16. How are heavy logs loaded on a sleigh or truck? How are barrels of
salt and sugar loaded and unloaded?

17. There are two hills of the same height. One has a gradual slope, the
other a steep one. Which is easier to climb? In what case is it farthest
to the top?