existed at the period referred to."

"The gentleman does not believe!" exclaimed Ardan. "The Chair must be
excused for reminding the honorable gentleman that it can not accept his
incredulity as a sound and valid argument. These two movements have
certainly equal periods now; why not always?"

"For the simple reason that this equality of periods is due altogether
to the influence of terrestrial attraction," replied the ready Captain.
"This attraction at present, I grant, is so great that it actually
disables the Moon from revolving on herself; consequently she must
always keep the same face turned towards the Earth. But who can assert
that this attraction was powerful enough to exert the same influence at
the epoch when the Earth herself was only a fluid substance? In fact,
who can even assert that the Moon has always been the Earth's
satellite?"

"Ah, who indeed?" exclaimed Ardan. "And who can assert that the Moon did
not exist long before the Earth was called into being at all? In fact,
who can assert that the Earth itself is not a great piece broken off the
Moon? Nothing like asking absurd questions! I've often found them
passing for the best kind of arguments!"

"Friend Ardan," interposed Barbican, who noticed that the Captain was a
little too disconcerted to give a ready reply; "Friend Ardan, I must say
you are not quite wrong in showing how certain methods of reasoning,
legitimate enough in themselves, may be easily abused by being carried
too far. I think, however, that the Captain might maintain his position
without having recourse to speculations altogether too gigantic for
ordinary intellect. By simply admitting the insufficiency of the
primordeal attraction to preserve a perfect balance between the
movements of the lunar rotation and revolution, we can easily see how
the nights and days could once succeed each other on the Moon exactly as
they do at present on the Earth."

"Nothing can be clearer!" resumed the brave Captain, once more rushing
to the charge. "Besides, even without this alternation of days and
nights, life on the lunar surface was quite possible."

"Of course it was possible," said Ardan; "everything is possible except
what contradicts itself. It is possible too that every possibility is a
fact; therefore, it _is_ a fact. However," he added, not wishing to
press the Captain's weak points too closely, "let all these logical
niceties pass for the present. Now that you have established the