For the inhabitants of Venus the study of the earth must be the most absorbing branch of observational astronomy, and the subject, we may imagine, of numberless volumes of learned memoirs, far exceeding in the definiteness of their conclusions the books that we have written about the physical characteristics of other members of the solar system.

And, if we are to look for attempts on the part of the inhabitants of other worlds to communicate with us by signals across the ether, it would certainly seem that Venus is the most likely source of such efforts, for from no other planet can those features of the earth that give evidence of its habitability be so clearly discerned.

Of one thing it would seem we may be certain: if Venus has intellectual inhabitants they possess far more convincing evidence of our existence than we are likely ever to have of theirs.
In referring to the view of the earth from Mercury it was remarked that the moon is probably visible to the naked eye.

From Venus the moon is not only visible, but conspicuous, to the naked eye, circling about the earth, and appearing at times to recede from it to a distance of about half a degree--equal to the diameter of the full moon as we see it.

The disk of the earth is not quite four times greater in diameter than that of the moon, and nowhere else in the solar system is there an instance in which two bodies, no more widely different in size than are the moon and the earth, are closely linked together.