Chapter 20 - Page 2

precisely my very weakness
which constitutes my strength."

"Your weakness amounts to folly," retorted the unknown in a passion.

"All the better," replied our Frenchman, "if it carries me up to
the moon."

Barbicane and his colleagues devoured with their eyes the intruder
who had so boldly placed himself in antagonism to their enterprise.
Nobody knew him, and the president, uneasy as to the result of so
free a discussion, watched his new friend with some anxiety.
The meeting began to be somewhat fidgety also, for the contest
directed their attention to the dangers, if not the actual
impossibilities, of the proposed expedition.

"Sir," replied Ardan's antagonist, "there are many and
incontrovertible reasons which prove the absence of an
atmosphere in the moon. I might say that, _a priori_, if one
ever did exist, it must have been absorbed by the earth; but I
prefer to bring forward indisputable facts."

"Bring them forward then, sir, as many as you please."

"You know," said the stranger, "that when any luminous rays
cross a medium such as the air, they are deflected out of the
straight line; in other words, they undergo refraction. Well!
When stars are occulted by the moon, their rays, on grazing the
edge of her disc, exhibit not the least deviation, nor offer the
slightest indication of refraction. It follows, therefore, that
the moon cannot be surrounded by an atmosphere.

"In point of fact," replied Ardan, "this is your chief, if not
your _only_ argument; and a really scientific man might be
puzzled to answer it. For myself, I will simply say that it is
defective, because it assumes that the angular diameter of the
moon has been completely determined, which is not the case.
But let us proceed. Tell me, my dear sir, do you admit the
existence of volcanoes on the moon's surface?"

"Extinct, yes! In activity, no!"

"These volcanoes, however, were at one time in a state of activity?"

"True, but, as they furnish themselves the oxygen necessary for
combustion, the mere fact of their eruption does not prove the
presence of an atmosphere."

"Proceed again, then; and let us set aside this class of
arguments in order to come to direct observations. In 1715 the
astronomers Louville and Halley, watching the eclipse of the
3rd of May, remarked some very extraordinary scintillations.
These jets of light, rapid in nature, and of frequent recurrence,
they attributed to thunderstorms generated in the lunar atmosphere."

"In 1715," replied the unknown, "the astronomers Louville and
Halley mistook for lunar phenomena some which were purely
terrestrial, such as meteoric or other bodies which are
generated in our own atmosphere. This was the