arguments against the habitability of the worlds. The conditions
of life must evidently be greatly modified upon the majority
of them. To mention only the planets, we should be either
broiled alive in some, or frozen to death in others, according
as they are more or less removed from the sun."

"I regret," replied Michel Ardan, "that I have not the honor of
personally knowing my contradictor, for I would have attempted
to answer him. His objection has its merits, I admit; but I
think we may successfully combat it, as well as all others which
affect the habitability of other worlds. If I were a natural
philosopher, I would tell him that if less of caloric were set
in motion upon the planets which are nearest to the sun, and
more, on the contrary, upon those which are farthest removed
from it, this simple fact would alone suffice to equalize the
heat, and to render the temperature of those worlds supportable
by beings organized like ourselves. If I were a naturalist,
I would tell him that, according to some illustrious men of
science, nature has furnished us with instances upon the earth
of animals existing under very varying conditions of life;
that fish respire in a medium fatal to other animals; that
amphibious creatures possess a double existence very difficult
of explanation; that certain denizens of the seas maintain life
at enormous depths, and there support a pressure equal to that
of fifty or sixty atmospheres without being crushed; that
several aquatic insects, insensible to temperature, are met with
equally among boiling springs and in the frozen plains of the
Polar Sea; in fine, that we cannot help recognizing in nature a
diversity of means of operation oftentimes incomprehensible, but
not the less real. If I were a chemist, I would tell him that