, and is
traceable round the greater portion of the declivity. Under a moderately
high sun, an oval area, nearly as large and fully as brilliant as the
central mountain, is seen on this inner slope. It is bordered on either
side by bands of a duskier hue, which probably represent shallow
transverse valleys. From its dazzling brilliancy it is very difficult to
observe the interior satisfactorily. In addition, however, to the central
mountain, there is a crater on the N.W. side of the floor. On the S. side
of Aristarchus is a large dusky ring some 10 miles in diameter, connected
by ridges with the spurs from the wall, and on the S.E., close to the
foot of the slope, is another smaller ring of a like kind.

HERODOTUS.--This far less brilliant but equally interesting object is
about 23 miles in diameter, and is not so regular in shape as
Aristarchus. Its W. wall rises at one point more than 4000 feet above the
very dusky floor. Except on the S.W. and N.E., the border is devoid of
detail. On the S.W. three little notches may be detected on its summit,
which probably represent small craters, while on the opposite side, on
the inner slope, a little below the crest, is a large crater, easily
seen. Both the E. and W. sections of the wall are prolonged towards the
S. far beyond the limits of the formation. These rocky masses, with an
intermediate wall, are very conspicuous under oblique illumination, that
on the S.W. being especially brilliant. On the N. there is a gap through
which the well-known serpentine cleft passes on to the floor. Between the
N.W. side of Herodotus and Aristarchus is a large plateau, seen to the
best advantage when the morning terminator lies a little distance E. of
the former. It is traversed by a T-shaped cleft which communicates with
the great serpentine cleft and extends towards the S. end of Aristarchus,
till it meets a second cleft (forming the upper part of the T) running
from the S.E. side of this formation along the W. side of Herodotus. The
great serpentine cleft, discovered by Schroter, October 7, 1787, is in
many respects the most interesting object of its class. It commences at
the N. end of a short wide valley, traversing mountains some distance
N.E. of Herodotus, as a comparatively delicate cleft. After following a
somewhat irregular course towards the N.W. for about 50 miles, and
becoming gradually wider and deeper, it makes a sudden turn and runs for
about 10 miles in a S.W. direction. It t