f by magic. In the beginning it was not such an easy job,
and those who led the way in the building and running of electric cars
had many difficulties to contend with and many obstacles to overcome
before they made the electric street-car the practical everyday affair
that it is now.

Just look first at your electric motor. It is, like all electrical
instruments and machines, a pretty delicate affair, very likely to
suffer serious injury from hard usage or exposure to bad weather.

To place such a machine underneath a jolting car close to the surface of
the street, and make it work properly at all times and in all weathers,
is no small feat. One great difficulty was to keep the wire coils of the
motor properly insulated. If two neighboring coils get connected with
each other the motor goes wrong, and as water is a powerful conductor of
electricity such accidents often happened at first through parts of the
motor getting wet from splashings from the street. Now motors are made
water-proof, and the cars go along merrily, even though there may be an
inch or two of water in the streets, or several inches of snow or slush.

The motor is attached to the frame of the car-truck, and the power is
transmitted to the axle of the car by means of gearing. In some electric
locomotives that have been made the armature of the motor is wound on
the axle itself, but for ordinary street cars it is found best to keep
the motor separate from the axle, and to transmit the power by geared
wheels.

[Illustration: THE TROLLEY-CAR.]

The current reaches the motor under the car by means of the
trolley-wheel and pole. The trolley-wheel is a solid copper wheel,
deeply grooved, which is pressed upward against the bare copper wire
stretched over the middle of the track; the long flexible pole which
carries the trolley-wheel has a strong spring which tends to press it
forward, and so keeps the wheel always firmly pressed against the wire
however much the car may jump about in rough places. An insulated wire
connected with the trolley-wheel is led down the pole and through the
car to the switches and regulating boxes placed at either end of the
car, just against the dash-board. No current can reach the motor without
passing through the switch and regulating box under control of the
motorman. With the switch the motorman can turn the current on or off
completely, he can regulate the amount of current that reaches the motor
so as to start gradually