THIRD QUADRANT.
Tycho. The largest and best known system on the visible surface.
Zuchius. A remarkable ray-system, but one which is only well seen when libration is favourable.
Bailly. N. of the centre of this great enclosure are two very distinct radiating streaks.
Schickard. Four conspicuous light spots, probably craters, on the S.E.
Byrgius A. A brilliant ray-centre, most of the rays trending eastward from a nimbus.
Hainzel. There are several bright spots E. of this formation.
Mersenius. Two or three light-rays originate from a point on the W. rampart.
Mersenius C. A light-surrounded crater with short rays.
Grimaldi. There are three bright spots on the W. wall.