perfectly motionless, and, consequently, the travellers knew that it
must be animated by the same ascensional movement as themselves.

"What on earth can such a consarn be, Barbican?" asked Ardan, who every
now and then liked to ventilate his stock of American slang. "Is it one
of those particles of meteoric matter you were speaking of just now,
caught within the sphere of our Projectile's attraction and accompanying
us to the Moon?"

"What I am surprised at," observed the Captain, "is that though the
specific gravity of that body is far inferior to that of our Projectile,
it moves with exactly the same velocity."

"Captain," said Barbican, after a moment's reflection, "I know no more
what that object is than you do, but I can understand very well why it
keeps abreast with the Projectile."

"Very well then, why?"

"Because, my dear Captain, we are moving through a vacuum, and because
all bodies fall or move--the same thing--with equal velocity through a
vacuum, no matter what may be their shape or their specific gravity. It
is the air alone that makes a difference of weight. Produce an
artificial vacuum in a glass tube and you will see that all objects
whatever falling through, whether bits of feather or grains of shot,
move with precisely the same rapidity. Up here, in space, like cause and
like effect."

"Correct," assented M'Nicholl. "Everything therefore that we shall throw
out of the Projectile is bound to accompany us to the Moon."