also. Kepler is the centre of one of the most
extended systems of bright streaks on the moon's visible surface.

BESSARION.--A bright little ring-plain, about 6 miles in diameter, in the
Oceanus Procellarum N. of Kepler. There is a smaller and still brighter
companion on the N. (Bessarion E), standing on a light area. Bessarion
has a minute central hill, difficult to detect.

PYTHEAS.--A small rhomboidal-shaped ring-plain, 12 miles in diameter,
standing in an isolated position on the Mare Imbrium between Lambert and
Gay-Lussac. Its bright walls, rising about 2500 feet above the Mare, are
much terraced within, especially on the E. There is a bright little
crater on the N. outer slope, with a short serpentine ridge running up to
it from the region S. of Lambert, and another winding ridge extending
from the S. wall to the E. of two conspicuous craters, standing about
midway between Pytheas and Gay-Lussac. The former bears a great
resemblance to the ridge N. of Madler, and, like this, appears to
traverse the N. border. The interior of Pytheas, which is depressed more
than 2000 feet below the Mare, includes a brilliant central peak.

LAMBERT.--A ring-plain, 17 miles in diameter, presenting many noteworthy
features. The crest of its border stands about 2000 feet above the Mare
Imbrium, and more than double this height above the interior. The wall is
prominently terraced both within and without; the outer slope on the W.
exhibiting at sunrise a nearly continuous valley running round it. When
near the morning terminator, the region on the N. is seen to be traversed
by some very remarkable ridges and markings; one cutting across the N.
wall appears to represent a "fault." On the S. is a large polygonal
enclosure formed by low ridges. On the W., towards Timocharis, is a
brilliant mountain 3000 feet high, a beautiful little object under a low
sun.

LEVERRIER.--The more westerly of a pair of little ring-plains on the N.
side of the Mare Imbrium, and S.W. of the Laplace promontory. It is about
10 miles in diameter, with walls rising some 1500 feet above the Mare,
and more than 6000 feet above the interior, which seems to be without a
central mountain or other features. Schmidt shows the crater on the N.
rim and another on the S.E. slope, both of which are omitted by Neison,
though they are easy objects when Helicon is on the morning terminator.
About 20 miles on the S.E. there is a very bright little crater on a
faint light area