runs in the same direction up to a small
crater near the N. end of another cape-like projection. At 8 h. on April
9, 1886, when the morning terminator bisected Sabine, I traced it still
farther in the same direction. All these clefts exhibit considerable
variations in width, but become narrower as they proceed westwards.

RITTER.--Is very similar in every respect to the last. A curved rill
mentioned by Neison is on the N.E. side of the floor and is concentric
with the wall. On the N. side of this ring-plain are three conspicuous
craters, the two nearer being equal in size and the third much smaller.

SCHMIDT.--A bright crater at the foot of the S. slope of Ritter.

DIONYSIUS.--This crater, 13 miles in diameter, is one of the brightest
spots on the lunar surface. It stands on the E. border of the Mare, about
30 miles E.N.E. of Ritter. A distinct crater-row runs round its outer
border on the W., and ultimately, as a delicate cleft, strikes across the
Mare to the E. side of Ritter. Both crater-row and cleft are easy objects
in a 4 inch achromatic under morning illumination.

ARIADAEUS.--A bright little crater of polygonal shape, with another
crater of about one-third the area adjoining it on the N.W., situated on
the rocky E. margin of the Mare Tranquilitatis, N.E. of Ritter. A short
cleft runs from it towards the latter, but dies out about midway. A
second cleft begins near its termination, and runs up to the N.E. wall of
Ritter. E. of this pair a third distinct cleft, originating at a point on
the coast-line about midway between Ariadaeus and Dionysius, ends near
the same place on the border. There is a fourth cleft extending from the
N. side of a little bay N. of Ariadaeus across the Mare to a point N.W.
of the more northerly of the three craters N. of Ritter. At a small
crater on the S. flank of the mountains bordering the little bay N. of
Ariadaeus originates one of the longest and most noteworthy clefts on the
moon's visible surface, discovered more than a century ago by Schroter of
Lilienthal. It varies considerably in breadth and depth, but throughout
its course over the plain, between Ariadaeus and Silberschlag, it can be
followed without difficulty in a very small telescope. E. of the latter
formation, towards Hyginus (with which rill-system it is connected), it
is generally more difficult. A few miles E. of Ariadaeus it sends out a
short branch, running in a S.W. direction, which can be traced as a fine
white