Thus, if a current be sent through the armature of the Gramme
machine, shown in figure 41, the armature will revolve, and the
spindle, by means of a belt on the pulley P, can communicate its
energy to another machine.

Hence the electric motor can be employed to work lathes, hoists,
lifts, drive the screws of boats or the wheels of carriages, and
for many other purposes. There are numerous types of electric
motor as of the dynamo in use, but they are all modifications of
the simple continuous or alternating current dynamo.

Obviously, since mechanical power can be converted into
electricity by the dynamo, and reconverted into mechanical power
by the motor, it is sufficient to connect a dynamo and motor
together by insulated wire in order to transmit mechanical power,
whether it be derived from wind, water, or fuel, to any reasonable
distance.





CHAPTER V.

ELECTROLYSIS.


Having seen how electricity can be generated and stored in
considerable quantity, let us now turn to its practical uses. Of
these by far the most important are based on its property of