considered
worthy of a man of his scientific eminence, so the name was transferred
to the formation we were looking upon. It is about 143 miles long and
very irregular in shape, and its depth is about 24,000 feet--so deep, in
fact, that the sun's light never reaches to the bottom; thus, when we
look at it from the earth, the floor is always in shadow.

The Leibnitz Mountains, unfortunately, were not visible, as the sun had
set upon them. I, however, mentioned that this range comprises several
peaks which are believed to be the highest on the lunar surface,
reaching as they do an altitude of 30,000 feet, and, according to some
measurements, 40,000 feet. They are very difficult to measure, owing to
the fact that they are really situated on the farther side of the moon,
extending east and west of the south pole, and are only occasionally
brought into view by the moon's libration; even then they are seen in
profile, and so situated that they cannot be measured with certainty.
They are, however, so high that they blunt the southern cusp of the moon
when it is in crescent form.

I now directed M'Allister to turn the vessel in a north-easterly
direction, and we moved across to the last objects which I proposed to
examine. One was the large walled plain "Schickard"--about 135 miles in
diameter--which encloses several other rings; the other, which lies to
the south-east of it and close to the moon's south-eastern limb, is
probably the most unique object on the lunar surface. As we gazed upon
it I explained that the formation, which is known as "Wargentin," would
probably in the usual course of events have been a ring-plain about
fifty-four miles in diameter, but it really is a high plateau of that
size, with very low ramparts. It is evidently a ring-plain which became
filled to the brim with lava, or mud, that welled up from the interior
of the moon; and the mountain walls, being exceptionally strong and
without any breaks or gaps, withstood the enormous pressure of the lava,
which therefore solidified and formed the great plateau as we now see
it. The low ramparts, which we noticed here and there, are really the
isolated peaks and ridges of the mountains forming the walls. This is
the only known instance of such a formation; but probably others would
exist had not the walls of the rings given way under the pressure of the
lava. The walls of several ring-plains have been quite carried away,
and, in some cases so obliterated, th