diameter,
close to the limb, S.W. of Langrenus. There is a longitudinal ridge on
the floor. Between it and Langrenus are two large ring-plains with
central mountains, and on the N.E., La Peyrouse A, a bright crater,
adjoining which is La Peyrouse DELTA, one of the most brilliant spots on
the moon.

ANSGARIUS.--A ring-plain, 50 miles in diameter, still nearer to the limb
than the last.

BEHAIM.--A great ring-plain, 65 miles in diameter, S. of Ansgarius, and
connected with it by ridges. It has lofty walls and a central mountain.

HECATAEUS.--An immense walled-plain, 115 miles in length, on the S.W. of
Vendelinus, with a very irregular rampart and a conspicuous central
mountain. It is flanked E. and W. by other large enclosures, which can
only be seen to advantage when libration is favourable.

W. HUMBOLDT.--Though close to the limb, this enormous wall-surrounded
plain, some 130 miles in extreme length, and estimated to have an area of
12,000 square miles, is well worth observing under suitable conditions.
It ranks among the largest formations of its class, and in many respects
resembles Bailly on the S.E. limb. At one point on the E. a peak rises to
16,000 feet, and on the opposite side there are peaks nearly as high. The
floor contains some detail--a crater, nearly central, associated with
ridges, and two dark spots, one at the S. and the other at the N. end.

PHILLIPS.--Abuts on the E. side of W. Humboldt. It is a walled-plain,
about 80 miles in length, with a border much broken on the E., and
terraced within on the opposite side. There are many hills and ridges on
the floor.

LEGENDRE.--A fine ring-plain, 46 miles in diameter, on the S.E. of the
last. According to Schmidt, there is a crater on the S. side of the
floor. There is a small ring-plain, ADAMS, on the S.

PETAVIUS.--The third member of the great meridional chain: a noble
walled-plain, with a complex rampart, extending nearly 100 miles from N.
to S., which encloses a very rugged convex floor, traversed by many
shallow valleys, and includes a massive central mountain and one of the
most remarkable clefts on the visible surface. To observe these features
to the best advantage, the formation should be viewed when its W. wall is
on the evening terminator. At this phase a considerable portion of the
interior on the N. is obscured by the shadow of the rampart, but the
principal features on the S. half of the floor, and on the broad gently-
shelving slope of