“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
clockwork. 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 I. On top
of number I are laid rails on which another platform car, number II,
a quarter of a mile shorter than number I, is moved in precisely the
same way. Number II, in its turn, is surmounted by number III, moving
independently of the tiers beneath, and a quarter of a mile shorter
than number II. Number II is a mile and a half long; number III a mile
and a quarter. Above, on successive levels, are number IV, a mile long;
number V, three quarters of a mile; number VI, half a mile; number VII,
a quarter of a mile, and number VIII, a short passenger-car on top of
all.
“Each car moves upon the car beneath it, independently of all the
others, at the rate of a mile a minute. Each car has its own magnetic
engines. Well, the train being drawn up with the latter end of each car
resting against a lofty bumping-post at A, Tom Furnace, the gentlemanly
conductor, and Jean-Marie Rivarol, engineer, mount by a long ladder to
the exalted number VIII. The complicated mechanism is set in motion.
What happens?
[Illustration: Drawn by Reginald Birch
“‘THIS IS THE TACHYPOMP. DOES IT JUSTIFY THE NAME?’”]
“Number VIII runs a quarter of a mile in fifteen seconds, and reaches
the end of number VII. Meanwhile number VII has run a quarter of a
mile in the same time, and reached the end of number VI; number VI, a
quarter of a mile in fifteen seconds, and reached the end of number
V; number V, the end of number IV; number IV, of number III; number
III, of number II; number II, of number I. And number I, in fifteen
seconds, has gone its quarter of a mile along the ground track, and
has reached station B. All this has been done in fifteen seconds.
Wherefore, numbers I, II, III, IV, V, VI, VII, and VIII come to rest
against the bumping-post at B, at precisely the same second. We, in
number VIII, reach B just when number I reaches it. In other words, we
accomplish two miles in fifteen seconds. Each of the eight cars, moving
at the rate of a mile a minute, has contributed a quarter of a mile to
our journey, and has done its work in fifteen seconds. All the eight
did their work at once, during the same fifteen seconds. Consequently
we have been whizzed through the air at the somewhat startling speed of
seven and a half seconds to the mile. This is the Tachypomp. Does it
justify the name?”
[Illustration: Drawn by Reginald Birch
“IN FRONT OF ME STOOD PROFESSOR SURD HIMSELF, LOOKING DOWN WITH A NOT
UNPLEASANT SMILE”]
Although a little bewildered by the complexity of cars, I apprehended
the general principle of the machine. I made a diagram, and understood
it much better. “You have merely improved on the idea of my moving
faster than the train when I was going to the smoking-car?” I said.
“Precisely. So far we have kept within the bounds of the practicable.
To satisfy the professor, you can theorize in something after this
fashion: if we double the number of cars, thus decreasing by one half
the distance which each has to go, we shall attain twice the speed.
Each of the sixteen cars will have but one eighth of a mile to go. At
the uniform rate we have adopted, the two miles can be done in seven
and a half instead of fifteen seconds. With thirty-two cars, and a
sixteenth of a mile, or twenty rods difference in their length, we
arrive at the speed of a mile in less than two seconds; with sixty-four
cars, each traveling but ten rods, a mile under the second. More than
sixty miles a minute! If this isn’t rapid enough for the professor,
tell him to go on increasing the number of his cars and diminishing
the distance each one has to run. If sixty-four cars yield a speed of
a mile inside the second, let him fancy a Tachypomp of six hundred and
forty cars, and amuse himself calculating the rate of car number 640.
Just whisper to him that when he has an infinite number of cars with an
infinitesimal difference in their lengths, he will have obtained that
infinite speed for which he seems to yearn. Then demand Abscissa.”
I wrung my friend’s hand in silent and grateful admiration. I could say
nothing.
“You have listened to the man of theory,” he said proudly. “You
shall now behold the practical engineer. We will go to the west of
the Mississippi and find some suitably level locality. We will erect
thereon a model Tachypomp. We will summon thereunto the professor,
his daughter, and why not his fair sister Jocasta as well? We will
take them on a journey which shall much astonish the venerable Surd.
He shall place Abscissa’s digits in yours and bless you both with an
algebraic formula. Jocasta shall contemplate with wonder the genius of
Rivarol. But we have much to do. We must ship to St. Joseph the vast
amount of material to be employed in the construction of the Tachypomp.
We must engage a small army of workmen to effect that construction, for
we are to annihilate time and space. Perhaps you had better see your
bankers.”