rails on which another platform car, number 2, a
quarter of a mile shorter than number 1, is moved in precisely the same
way. Number 2, in its turn, is surmounted by number 3, moving
independently of the tiers beneath, and a quarter of a mile shorter than
number 2. Number 2 is a mile and a half long; number 3 a mile and a
quarter. Above, on successive levels, are number 4, a mile long; number
5, three quarters of a mile; number 6, half a mile; number 7, a quarter
of a mile, and number 8, 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 8. The complicated mechanism is set in motion. What
happens?

"Number 8 runs a quarter of a mile in fifteen seconds and reaches the
end of number 7. Meanwhile number 7 has run a quarter of a mile in the
same time and reached the end of number 6; number 6, a quarter of a mile
in fifteen seconds, and reached the end of number 5; number 5, the end
of number 4; number 4, of number 3; number 3, of number 2; number 2, of
number 1. And number 1, 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 1, 2, 3, 4, 5, 6, 7,
and 8 come to rest against the bumping-post at B, at precisely the same
second. We, in number 8, reach B just when number 1 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?"

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?"

"Precisely. So far we have kept within the bounds of the pract