etable life." [448] Some of these writers
may appear to be travelling rather too fast or too far, and their
assumptions may wear more of the aspect of plausibility than of
probability. But on their atmospheric and aqueous hypothesis,
vegetation in abundance is confessedly a legitimate consequence. If
a recent writer has liberty to condense into a sentence the conclusion
from the negative premiss in the argument by saying, "As there is
but a little appearance of water or air upon the moon, the conclusion
has been inferred that there exists no vegetable or animal life on that
globe," [449] other writers, holding opposite views of the moon's
physical condition, may be allowed to expatiate on the luxuriant
life which an atmosphere with water and temperature would
undoubtedly produce. Mr. Proctor's tone is temperate, and his
language that of one who is conscious with Hippocrates that "art is
long and life is short." He says, in one of his contributions to lunar
science, "It may safely be asserted that the opportunities presented
during the life of any single astronomer for a trustworthy
investigation of any portion of the moon's surface, under like
conditions, are few and far between, and the whole time so
employed must be brief, even though the astronomer devote many
more years than usual to observational research." [450] This
prepares us to find in another of the same author's works the
following suggestive sentence: "With regard to the present
habitability of the moon, it may be remarked that we are not
justified in asserting positively that no life exists upon her surface.
Life has been found under conditions so strange, we have been so
often mistaken in assuming that _here_ certainly, or _there_, no
living creatures can possibly exist, that it would be rash indeed to
dogmatise respecting the state of the moon in this respect." [451]
Narrien, one of the historians of the science, may be heard, though
his contribution might be cast into either scale. He writes: "The
absence of those variations of light and shade which would be
produced by clouds floating above her surface, and the irregularities
of the ground, visible at the bottom and on the sides of her cavities,
have given reason to believe that no atmosphere surrounds her, and
that she is destitute of rivers and seas. Such are the opinions
generally entertained concerning the moon; but M. Schroeter, a
German astronomer, ventures to assert that our satellite is the abo