its use in the construction of airships, the problem of aerial
navigation on Mars had been solved.

Almos' knowledge of such matters made me instantly aware of all this the
moment the question of buoyancy presented itself in my mind, but,
although I could not help marveling at the ingenuity of this wonderful
people, I outwardly preserved the calm demeanor which Almos' strong
personality had made a characteristic. Indeed, Reon, who had been
preparing an aerenoid for our use--such was the Martian name for these
airships--was quite unaware of my astonishment, and it was plain that
with the exercise of due care, when I spoke without the prompting of
Almos' knowledge, there was no likelihood of anyone's having a suspicion
of my true personality.

The aerenoid in which we were going to make our journey differed in
appearance considerably from those which I saw floating about us.
Cigar-shaped, with windows in its sides and roof like a steamer's
portholes, it more nearly resembled a submarine boat than an airship, as
it rested on a platform built in the side of the balcony for the
purpose. Yet such was the repelling force of this wonderful metal which
the Martians had discovered, and which I found was attached in two or
more strips to the bottom of the aerenoids, that the matter of weight in
their construction was of little importance. While resting on the
ground these strips were encased in a material that was a non-conductor,
thus neutralizing the repelling force. In order to raise the car the
casing was merely drawn back by means of a controlling lever, until
enough of the metal was exposed to the surface of Mars to cause the
repelling force to lift the aerenoid, and by preserving this exposure,
any desired height could thus be attained.