curvature being apparent where these sections meet. The crest on the
S. and S.E. exhibits many breaks and irregularities; and it is through a
narrow gap on the S. that a rill-like valley, originating at a small
depression near the foot of the S.W. _glacis_, passes, and, descending
the inner slope of the S.E. wall obliquely, terminates near its foot.
There is a distinct crater on the summit ridge on the S.E., and another
below the crest on the outer S.W. slope. On the S. inner slope I have
often remarked a number of bright oval objects, which, for the lack of a
better word, may be termed "mounds" though they represent masses of
material many miles in length and breadth. The outer slope of Tycho,
exhibiting under a high light a grey nimbus encircling the wall,
includes--craters, crater-pits, shallow valleys, spurs and buttresses--in
short, almost every variety of lunar feature is represented. Excepting
the central mountain and a crater on the W. of it, I have not seen any
object on the floor, which, for some unexplained reason, is never very
distinct. Schmidt shows several low ridges on the N.E. side. In a paper
recently published in the _Astronomische Nachrichten_, Professor W.H.
Pickering, describing his observations of the Tycho streaks made at
Arequipa, Peru, with a 13 inch achromatic, asserts that they do not
radiate from the centre of Tycho, but from a multitude of minute craters
on its S.E. or N. rim. (See Introduction.)

MAGINUS.--An immense partially ruined enclosure, at least 100 miles from
side to side, on the S.W. of Tycho, from which it is separated by a
region covered with a confused mass of ring-plains and craters. On almost
every part of its broken border stand large ring-plains, many of which,
if they were isolated, or situated in a less disturbed region, would rank
as objects of importance; but among such a multitude of features they
pass unnoticed. The largest of them occupies no inconsiderable part of
the S.E. wall, and is quite 30 miles in diameter, its own border being
also much broken by depressions, as, indeed, are those of almost all the
six or more large ring-plains which define the N. limits of Maginus. The
loftiest portion of what remains of a true border rises at one place to
more than 14,000 feet. On the floor, which is traversed by some of the
Tycho rays, there is a mountain group associated with a crater, nearly
central, and several large rings on the N. side. Though the formation is
very di