n, could not help falling on her
surface, just as an aerolite cannot help falling on our Earth.

"Softly, dear boy, softly," replied Barbican; "aerolites _can_ help
falling on the Earth, and the proof is, that few of them _do_ fall--most
of them don't. Therefore, even granting that we had already assumed the
nature of an aerolite, it does not necessarily follow that we should
fall on the Moon."

"But," objected Ardan, "if we approach only near enough, I don't see how
we can help--"

"You don't see, it may be," said Barbican, "but you can see, if you only
reflect a moment. Have you not often seen the November meteors, for
instance, streaking the skies, thousands at a time?"

"Yes; on several occasions I was so fortunate."

"Well, did you ever see any of them strike the Earth's surface?" asked
Barbican.

"I can't say I ever did," was the candid reply, "but--"

"Well, these shooting stars," continued Barbican, "or rather these
wandering particles of matter, shine only from being inflamed by the
friction of the atmosphere. Therefore they can never be at a greater
distance from the Earth than 30 or 40 miles at furthest, and yet they
seldom fall on it. So with our Projectile. It may go very close to the
Moon without falling into it."

"But our roving Projectile must pull up somewhere in the long run,"
replied Ardan, "and I should like to know where that somewhere can be,
if not in the Moon."

"Softly again, dear boy," said Barbican; "how do you know that our
Projectile must pull up somewhere?"

"It's self-evident," replied Ardan; "it can't keep moving for ever."

"Whether it can or it can't depends altogether on which one of two
mathematical curves it has followed in describing its course. According
to the velocity with which it was endowed at a certain moment, it must
follow either the one or the other; but this velocity I do not consider
myself just now able to calculate."

"Exactly so," chimed in M'Nicholl; "it must describe and keep on
describing either a parabola or a hyperbola."

"Precisely," said Barbican; "at a certain velocity it would take a
parabolic curve; with a velocity considerably greater it should describe
a hyperbolic curve."

"I always did like nice corpulent words," said Ardan, trying to laugh;
"bloated and unwieldy, they express in a neat handy way exactly what you
mean. Of course, I know all about the high--high--those high curves, and
those low curves. No matter. Explain them to me all