includes a conspicuous central mountain, a large crater, and
other details. The best phase for observing Hommel and its surroundings
is when the W. wall is just within the evening terminator.

PITISCUS.--The most regular of the Vlacq group. It is situated on the
N.E. of Hommel (a curious oblong-shaped enclosure, Hommel _h_, with a
very attenuated E. wall, and a large crater on a floor, standing at a
higher level than that of Pitiscus, intervening). It is 52 miles in
diameter, and is surrounded by an apparently continuous rampart, except
on the E., where there is a crater, and on the S.W., where it abuts on
Hommel _h_. Here there is a wide gap crossed by what has every appearance
of being a "fault," resembling that in Phocylides on a smaller scale.
There is a fine crater on the N. side of the interior connected with the
S. wall by a bright ridge. Just beyond the E. border there is a shallow
ring-plain of a very extraordinary shape.

NEARCH.--A ring-plain, about 35 miles in diameter, on the S.W. of Hommel,
forming part of the Vlacq group.

TANNERUS.--A ring-plain, about 19 miles in diameter, between Mutus and
Bacon. It has a central mountain.

MUTUS.--A fine but foreshortened walled plain, 51 miles in diameter.
There are two ring-plains of about equal size on the floor, one on the
N., and the other on the S. side. The wall on the W. rises to nearly
14,000 feet above the interior.

MANZINUS.--A walled plain, nearly 62 miles in diameter, with a terraced
rampart rising to a height of more than 14,500 feet above the interior.
Schmidt shows three craterlets on the floor, but no traces of the small
central peak which is said to stand thereon, but to be only visible in
large telescopes.

SCHOMBERGER.--A large walled-plain adjoining Simpelius on the S.W. Too
near the limb for satisfactory observation.

WEST LONGITUDE 20 deg. TO 0 deg.

DELAMBRE.--A conspicuous ring-plain, 32 miles in diameter, a little S. of
the equator, in W. long. 17 deg. 30 min., with a massive polygonal
border, terraced within, rising on the W. to the great height of 15,000
feet above the interior, but to little more than half this on the
opposite side. Its outline approximates to that of a pentagon with
slightly curved sides. A section on the S.E. exhibits an inflexion
towards the centre. The crest is everywhere continuous except on the N.,
where it is broken by a deep crater with a bright rim. The north-easterly
trend of the ridges and hillock