miles in diameter, intrudes far within the limits of
the formation on the E., and its towering crest rises more than 10,000
feet above its floor, on which there is a small central mountain. The
central mountain of Albategnius is more than 4000 feet high, and, with
the exception of a few minor elevations, is the only prominent feature in
the interior, though there are many small craters. Schmidt counted forty
with the Berlin refractor, among them 12 on the E. side, arranged like a
string of pearls.

PARROT.--An irregularly-shaped formation, 41 miles in diameter, S. of
Albategnius, with a very discontinuous margin, interrupted on every side
by gaps and depressions, large and small; the most considerable of which
is the regular ring-plain Parrot _a_, on the E. An especially fine
valley, shown by Schmidt to consist in part of large inosculating
craters, cuts through the wall on the S.W., and runs on the E. side of
Argelander towards Airy. The floor of Parrot is very rugged.

DESCARTES.--This object, about 30 miles in diameter, situated N.W. of
Abulfeda, is bounded by ill-defined, broken, and comparatively low walls;
interrupted on the S.E. by a fine crater, Descartes A, and on the S.W. by
another, smaller. There is also a brilliant crater outside on the N.W.
Schmidt shows a crater-row on the floor, which I have seen as a cleft.

DOLLOND.--A bright crater, about 6 miles in diameter, on the N.E. side of
Descartes. Between it and the latter there is a rill-valley.

TACITUS.--A bright ring-plain, about 28 miles in diameter, a few miles E.
of Catherina, with a lofty wall rising both on the E. and W. to more than
11,000 feet above the floor. Its continuity is broken on the N. by a gap
occupied by a depression, and there is a conspicuous crater below the
crest on the S.W. The central mountain is connected with the N. wall by a
ridge, recalling the same arrangement within Madler. A range of lofty
hills, an offshoot of the Altai range, extends from Tacitus towards
Fermat.

ALMANON.--This ring-plain, with its companion Abulfeda on the N.E., is a
very interesting telescopic object. It is about 36 miles in diameter, and
is surrounded by an irregular border of polygonal shape, the greatest
altitude of which is about 6000 feet above the floor on the W. It is
slightly terraced, and is broken on the S. by a deep crater pertaining to
the bright and large formation Tacitus _b_, the E. border of which casts
a fine double-peaked shadow at