similar to life
on the earth, is altogether improbable, if not absolutely impossible.

The replies given to this query will be by no means unanimous. But,
for the full understanding of the state of the main question, and to
assist us in arriving at some sort of verdict, we will hear several
authorities on both sides of the case. The evidence being
cumulative, we pursue the chronological order, and begin with La
Place. He writes: "The lunar atmosphere, if any such exists, is of an
extreme rarity, greater even than that which can be produced on the
surface of the earth by the best constructed air-pumps. It may be
inferred from this that no terrestrial animal could live or respire at
the surface of the moon, and that if the moon be inhabited, it must
be by animals of another species." [428] This opinion, as Sir David
Brewster points out, is not that the moon has no atmosphere, but
that if it have any it is extremely attenuated. Mr. Russell Hind's
opinion is similar with respect to water. He says: "Earlier
selenographists considered the dull, grayish spots to be water, and
termed them the lunar seas, bays, and lakes. They arc so called to
the present day, though we have strong evidence to show that if
water exist at all on the moon, it must be in very small quantity."
[429] Mr. Grant tells us that "the question whether the moon
be surrounded by an atmosphere has been much discussed by
astronomers. Various phenomena are capable of indicating such an
atmosphere, but, generally speaking, they are found to be
unfavourable to its existence, or at all events they lead to the
conclusion that it must be very inconsiderable." [430] Humboldt
thinks that Schroeter's assumptions of a lunar atmosphere and lunar
twilight are refuted, and adds: "If, then, the moon is without any
gaseous envelope, the entire absence of any diffused light must
cause the heavenly bodies, as seen from thence, to appear projected
against a sky _almost black_ in the day-time. No undulation of air
can there convey sound, song, or speech. The moon, to our
imagination, which loves to soar into regions inaccessible to full
research, is a desert where silence reigns unbroken." [431] Dr.
Lardner considers it proven "that there does not exist upon the moon
an atmosphere capable of reflecting light in any sensible degree,"
and also believes that "the same physical tests which show the
non-existence of an atmosphere of air upon the moon are equally
conclusive against