raphy has come to the assistance of the
observer, Mr. Birt's proposal, if confined within narrower limits, would
be far less arduous an undertaking than before, and might be easily
carried out. A complete photographic survey of a few selected regions, as
a basis for an equally thorough and exhaustive scrutiny by direct
observation, would, it is believed, lead to a much more satisfactory and
hopeful method for ultimately furnishing irrefragable testimony as to
permanency or change than any that has yet been undertaken.

CATALOGUE OF LUNAR FORMATIONS

FIRST QUADRANT

WEST LONGITUDE 90 deg. TO 60 deg.

SCHUBERT.--This ring-plain, about 46 miles in diameter, situated on the
N.E. side of the Mare Smythii, is too near the limb to be well observed.

NEPER.--Though still nearer the limb, this walled-plain, 74 miles in
diameter, is a much more conspicuous object. It has a lofty border and a
prominent central mountain, the highest portion of a range of hills which
traverses the interior from N. to S.

APOLLONIUS.--A ring-plain, 30 miles in diameter, standing in the
mountainous region S. of the Mare Crisium. There is a large crater on the
S.W. wall, and another, somewhat smaller, adjoining it on the N. There
are many brilliant craters in the vicinity.

FIRMICUS.--A somewhat larger, more regular, but, in other respects, very
similar ring-plain, N.W. of the last. Some distance on the W., Madler
noted a number of dark-grey streaks which apparently undergo periodical
changes, suggestive of something akin to vegetation. They are situated
near a prominent mountain situated in a level region.

AZOUT.--A small ring-plain, connected with the last by a lofty ridge. It
is the apparent centre of many other ridges and valleys which radiate
from it towards the N.W. and the Mare Crisium. There is a central
mountain, not an easy telescopic object, on its dusky floor.

CONDORCET.--A very prominent ring-plain, 45 miles in diameter, situated
on the mountainous S.W. margin of the Mare Crisium. It is encircled by a
lofty wall about 8000 feet in height. The dark interior of this and of
the three preceding formations render them easily traceable under a high
angle of illumination.

HANSEN.--A ring-plain, 32 miles in diameter, on the W. border of the Mare
Crisium N. of Condorcet. Schmidt shows a central mountain and a terraced
wall.

ALHAZEN.--This ring-plain, rather smaller than the last, is the most
northerly of the linear chain of