e
added your speed to that of the locomotive to some purpose. _Nicht
wahr?_"

I saw it perfectly; much plainer, perhaps, for his putting in the clause
about Abscissa.

He continued:

"This illustration, though a slow one, leads up to a principle which may
be carried to any extent. Our first anxiety will be to spare your legs
and wind. Let us suppose that the two miles of track are perfectly
straight, and make our train one platform car, a mile long, with
parallel rails laid upon its top. Put a little dummy engine on these
rails, and let it run to and fro along the platform car, while the
platform car is pulled along the ground track. Catch the idea? The dummy
takes your place. But it can run its mile much faster. Fancy that our
locomotive is strong enough to pull the platform car over the two miles
in two minutes. The dummy can attain the same speed. When the engine
reaches B in one minute, the dummy, having gone a mile a-top the
platform car, reaches B also. We have so combined the speeds of those
two engines as to accomplish two miles in one minute. Is this all we can
do? Prepare to exercise your imagination."

I lit my pipe.

"Still two miles of straight track, between A and B. On the track a long
platform car, reaching from A to within a quarter of a mile of B. We
will now discard ordinary locomotives and adopt as our motive power a
series of compact magnetic engines, distributed underneath the platform
car, all along its length."

"I don't understand those magnetic engines."

"Well, each of them consists of a great iron horseshoe, rendered
alternately a magnet and not a magnet by an intermittent current of
electricity from a battery, this current in its turn regulated by
clock-work. When the horseshoe is in the circuit, it is a magnet, and it
pulls its clapper toward it with enormous power. When it is out of the
circuit, the next second, it is not a magnet, and it lets the clapper
go. The clapper, oscillating to and fro, imparts a rotatory motion to a
fly-wheel, which transmits it to the drivers on the rails. Such are our
motors. They are no novelty, for trial has proved them practicable.

"With a magnetic engine for every truck of wheels, we can reasonably
expect to move our immense car, and to drive it along at a speed, say,
of a mile a minute.

"The forward end, having but a quarter of a mile to go, will reach B in
fifteen seconds. We will call this platform car number 1. On top of
number 1 are laid