Page:The evolution of worlds - Lowell.djvu/108

82 be discernible even at the distance we are off. Deltas of such inroad would thus seam the bounding circle of light and shade.

Another result of the aërial circulation would be the removal of all moisture from the sunward face, and its depositing in the form of ice upon the night one. For the heated air would be able to carry much water in suspension, which, on cooling, after it had reached the dark hemisphere would unload it there. In the low temperature there prevailing, this moisture would all be frozen, and so largely estopped from return. This process continuing for ages would finally deplete one side of all its water to heap it up in the form of ice upon the other.

Now it is not a little odd that a phenomenon has been observed upon Venus which seems to display just this state of things. Many observers have noted an ashen light on the dark side of her disk. Some have tried to account for it as Earth shine, the same earth-reflected light that makes dimly visible the old moon in the new moon's arms. But the Earth is too far away from Venus to permit of any such effect; nor is there any other body that could thus relieve its night. But if the night hemisphere of Venus be one vast polar sheet, we have there a substance able to mirror the stars to a ghostlike gleam which might be discernible even from our distant post.