thunderstorms, chemical action, and slow-moving
quadruple-expansion steam engines, provides the power required to
run our electric ships and water-spiders, railways, and
stationary and portable motors, for heating the cables laid along
the bottom of our canals to prevent their freezing in winter, and
for almost every conceivable purpose. Sometimes a man has a
windmill on his roof for light and heat; then, the harder the
wintry blasts may blow the brighter and warmer becomes the house,
the current passing through a storage battery to make it more
steady. The operation of our ordinary electric railways is very
simple: the current is taken from an overhead, side, or
underneath wire, directly through the air, without the
intervention of a trolley, and the fast cars, for they are no
longer run in trains, make five miles a minute. The entire
weight of each car being used for its own traction, it can ascend
very steep grades, and can attain high speed or stop very
quickly.

"Another form is the magnetic railway, on which the cars are
wedge-shaped at both ends, and moved by huge magnets weighing
four thousand tons each, placed fifty miles apart. On passing a
magnet, the nature of the electricity charging a car is
automatically changed from positive to negative, or vice versa,
to that of the magnet just passed, so that it repels while the
next attracts. The successive magnets are charged oppositely,
the sections being divided halfway between by insulators, the
nature of the electricity in each section being governed by the
charge in the magnet. To prevent one kind of electricity from
uniting with and neutralizing that in the next section by passing
through the car at the moment of transit, there is a "dead