the room, and soon these were closed and we felt an almost imperceptible
jar. The doctor glanced hastily at Thorwald and said:

"Can it be possible that we are to travel in this apartment?"

"Yes," answered Thorwald, "this is our modern traveling coach, and we are
already on our way to the city in which my friend here and I reside."

This latter fact surprised us, for we could not perceive by our senses
that we were in motion. But as we sat wondering and trying to imagine
ourselves flying through space, the doors opened, a pleasant breeze fanned
our cheeks, and the doors closed again, we felt that slight jar repeated,
and then we were quiet once more. This occurred every two or three
minutes, and, remembering what Thorwald had previously told us, we
realized that we were riding in a perfectly tight car in a vacuum tube and
that these short but frequent stops were to keep us supplied with fresh
air.

Thorwald explained this to us again, and told us that the coaches were of
different sizes to accommodate large or small parties, and that one could
ride alone if he chose to. The cars started so frequently that it was
seldom necessary to wait more than a few minutes. The doctor thought there
must be great liability to accident, but Thorwald said:

"No, we do not consider the risk worth taking into account. Let me
illustrate with a familiar example. Suppose you had just seen a cable
tested with a ton's weight without a strain. Should you fear to take hold
of the cable and lift yourself from the ground lest it might break and you
should fall? The mechanism of this road is just as sure as that. The force
that is driving us forward is no longer mysterious. The laws of