idences of an atmosphere, rare as compared with ours, yet manifest in
its effects; of variations of color witnessed in certain places as the
sunlight drifts over them at changing angles of incidence; of what seem
to be immense fields of vegetation covering level ground, and of
appearances indicating the existence of clouds of ice crystals and
deposits of snow among the mountainous lunar landscapes. Thus, in a
manner, the moon is rehabilitated, and we are invited to regard its
silvery beams not as the reflections of the surface of a desert, but as
sent back to our eyes from the face of a world that yet has some slight
remnants of life to brighten it.

The suggestion that there is an atmosphere lying close upon the shell of
the lunar globe, filling the deep cavities that pit its face and
penetrating to an unknown depth in its interior, recalls a speculation
of the ingenious and entertaining Fontenelle, in the seventeenth
century--recently revived and enlarged upon by the author of one of our
modern romances of adventure in the moon--to the effect that the lunar
inhabitants dwell beneath the surface of their globe instead of on the
top of it.

Now, because of this widespread and continually increasing interest in
the subject of other worlds, and on account of the many curious
revelations that we owe to modern telescopes and other improved means of
investigation, it is certainly to be desired that the most important and
interesting discoveries that have lately been made concerning the
various globes which together with the earth constitute the sun's
family, should be assembled in a convenient and popular form--and that
is the object of this book. Fact is admittedly often stranger and more
wonderful than fiction, and there are no facts that appeal more
powerfully to the imagination than do those of astronomy. Technical
books on astronomy usually either ignore the subject of the habitability
of the planets, or dismiss it with scarcely any recognition of the
overpowering human interest that it possesses. Hence, a book written
specially from the point of view of that subject would appear calculated
to meet a popular want; and this the more, because, since Mr. Proctor
wrote his Other Worlds than Ours and M. Flammarion his Pluralite des
Mondes Habites, many most important and significant discoveries have
been made that, in several notable instances, have completely altered
the aspect in which the planets present themselves for o