magnet, show pupils how to make a
telegraph sounder. (See Manual on _Manual Training_.) If possible,
examine the construction of an electric bell. The motor and electric
light are other common applications of the current. Take up the uses of
the motor in factories, and for running street-cars and automobiles.
Show the necessity for a water-wheel or engine to produce the current,
and for wires to connect. Explain that batteries are not used to produce
large currents, but that machines called dynamos, similar to motors,
when driven by steam or water-power, will yield electric currents as
batteries do.

STEAM

The power of steam may be shown by loosely corking a flask and boiling
the water in it until the cork is driven out, or by stopping the spout
of a boiling tea-kettle, or by letting a stream of steam impinge on a
toy paper wheel. Encourage pupils to learn all they can about steam and
gasolene engines and their uses.

FARM TOOLS

This topic should be dealt with only in so far as it can be made a
subject for actual observation by the pupils. Children should learn to
be thoughtful and observant and to do all kinds of work, manual as well
as mental, intelligently.

MACHINES

(Consult _The Ontario High School Physics_, Chap. IX.)

LEVER.--When a _lever_ is used to lift a log, one end is placed under
the log, a block called a _fulcrum_ is placed under the lever as close
as possible to the log, and then the workman pulls down on the outer end
of the lever. For example, if the fulcrum is one foot from the log and
ten feet from the man, the latter can raise ten pounds with a pull of
one pound, but he has to move his end of the lever ten times as far as
the log rises. Try it. See other examples in plough handles, see-saw,
balance, scissors, wheel-barrow, pump-handle, handspike, crowbar,
canthook, nut-crackers.

ROPE AND PULLEY.--In the _rope_ and _pulley_ note that when the pulley
is a fixed one, the only advantage is a changed direction of the rope.
When the pulley is _movable_, the horse pulling will have only half the
weight to draw if the pulley is single, one quarter if double, one sixth
if triple, etc. Thus in the case of a common hay-fork the horse draws
only half the weight of the hay, but he walks twice as far as the hay
moves.

COGS.--If one wheel has eighty _cogs_ and the other ten, the latter will
turn eight times to the former's once.

BELT.--When a _belt_ runs over two wheels, one having, say, o