ust evidently lie nearer to this focus in one part of its
orbit than in another. The Earth when nearest to the Sun, is in her
_perihelion_; when most distant, in her _aphelion_. The Moon, with
regard to the Earth, is similarly in her _perigee_, and her _apogee_.
Analogous expressions denoting the relations of the Projectile towards
the Moon, would be _periselene_ and _aposelene_. At its _aposelene_ the
Projectile's velocity would have reached its minimum; at
the _periselene_, its maximum. As it is to the former point that we are
now moving, clearly the velocity must keep on diminishing until that
point is reached. Then, _if it does not die out altogether_, it must
spring up again, and even accelerate as it reapproaches the Moon. Now
the great trouble is this: If the _Aposelenetic_ point should coincide
with the point of lunar attraction, our velocity must certainly become
_nil_, and the Projectile must remain relatively motionless forever!"

"What do you mean by 'relatively motionless'?" asked M'Nicholl, who was
carefully studying the situation.

"I mean, of course, not absolutely motionless," answered Barbican;
"absolute immobility is, as you are well aware, altogether impossible,
but motionless with regard to the Earth and the--"

"By Mahomet's jackass!" interrupted Ardan hastily, "I must say we're a
precious set of _imbeciles_!"

"I don't deny it, dear friend," said Barbican quietly, notwithstanding
the unceremonious interruption; "but why do you say so just now?"

"Because though we are possessed of the power of retarding the velocity
that takes us from the Moon, we have never thought of employing it!"

"What do you mean?"

"Do you forget the rockets?"

"It's a fact!" cried M'Nicholl. "How have we forgotten them?"

"I'm sure I can't tell," answered Barbican, "unless, perhaps, because we
had too many other things to think about. Your thought, my dear friend,
is a most happy one, and, of course, we shall utilize it."

"When? How soon?"

"At the first favorable opportunity, not sooner. For you can see for
yourselves, dear friends," he went on explaining, "that with the present
obliquity of the Projectile with regard to the lunar disc, a discharge
of our rockets would be more likely to send us away from the Moon than
towards her. Of course, you are both still desirous of reaching the
Moon?"

"Most emphatically so!"

"Then by reserving our rockets for the last chance, we may possibly get
there after all.