connected with the foot of the _glacis_
by a prominent ridge. On the bright central mountain, Schmidt, in 1842,
detected a crater, which is easily seen under a moderately high light.
Timocharis and the neighbourhood, especially the peculiar shape of the
terminator on the E. of the formation, is well worth examination at
sunrise.

PIAZZI SMYTH.--A conspicuous little ring-plain, 5 or 6 miles in diameter,
depressed about 1500 feet below the Mare Imbrium, with a border rising
about 2000 feet above it. With the curious arrangement of ridges, of
which it is the apparent centre, it is a striking object under a low sun.

KIRCH.--A rather smaller object of the same class on the S.E.

PLATO.--This beautiful walled-plain, 60 miles in diameter, with its
bright border and dark steel-grey floor, has, from the time of Hevelius
to the present, been one of the most familiar objects to lunar observers.
In the rude maps of the seventeenth century it figures as the "Lacus
Niger Major," an appellation which not inaptly describes its appearance
under a high sun, when the sombre tone of its apparently smooth interior
is in striking contrast to that of the isthmus on which the formation
stands. It will repay observation under every phase, and though during
the last thirty years no portion of the moon has been more diligently
scrutinised than the floor; the neighbourhood includes a very great
number of objects of every kind, which, not having received so much
attention, will afford ample employment to the possessor of a good
telescope during many lunations.

The border of Plato, varying in height from 3000 to 4000 feet above the
interior, is crowned by several lofty peaks, the highest (7400 feet)
standing on the N. side of the curious little triangular formation on the
E. wall. Those on the W., three in number, reckoning from N. to S., are
respectively about 5000, 6000, and 7000 feet in altitude above the floor.
The circumvallation being very much broken and intersected by passes,
exhibits many distinct breaches of continuity, especially on the S. There
is a remarkable valley on the S.W., which, cutting through the border at
a wide angle, suddenly turns towards the S.E., and descends the slope of
the _glacis_ in a more attenuated form. Another but shorter valley is
traceable at sunrise on the W. On the N.W., the rampart is visibly
dislocated, and the gap occupied by an intrusive mountain mass. This
dislocation is not confined to the wall, bu