term to the existence of the moon as a life-supporting world.

Suppose we examine two more of Mr Ritchey's illuminating photographs,
and, first, the one showing the crater Theophilus and its
surroundings. We have spoken of Theophilus before, citing the facts
that it is sixty-four miles in diameter and eighteen thousand feet
deep. It will be noticed that it has two brother giants -- Cyrillus
the nearer, and Catharina the more distant; but Theophilus is plainly
the youngest of the trio. Centuries, and perhaps thousands of years,
must have elapsed between the periods of their upheaval, for the two
older craters are partly filled with débris, while it is manifest at a
glance that when the south eastern wall of Theophilus was formed, it
broke away and destroyed a part of the more ancient ring of Cyrillus.
There is no more tremendous scene on the moon than this; viewed with a
powerful telescope, it is absolutely appalling.

The next photograph shows, if possible, a still wilder region. It is
the part of the moon lying between Tycho and the south pole. Tycho is
seen in the lower left-hand part of the picture. To the right, at the
edge of the illuminated portion of the moon, are the crater-rings,
Longomontanus and Wilhelm I, the former being the larger. Between them
are to be seen the ruins of two or three more ancient craters which,
together with portions of the walls of Wilhelm I and Longomontanus,
have been honeycombed with smaller craters. The vast crateriform
depression above the center of the picture is Clavius, an unrivaled
wonder of lunar scenery, a hundred and forty-two miles in its greatest
length, while its whole immense floor has sunk two miles below the
general surface of the moon outside the ring. The monstrous
shadow-filled cavity above Clavius toward the right is Blancanus,
whose aspect here gives a good idea of the appearance of these chasms