Part 25

D'Alembert Mountains. A very lofty range on the E. limb, extending to S. lat. 11 deg.

The Cordilleras. Close to the E. limb; they lie between S. lat. 8 deg. and S. lat. 23 deg.

Rook Mountains. On the E. limb, extending from about S. lat. 18 deg. to S. lat. 35 deg. According to Schroter, they attain a height of 25,000 feet.

Dorfel Mountains. On the S.E. limb between S. lat. 57 deg. and S. lat. 80 deg.

Leibnitz Mountains. On the S. limb extending W. from S. lat. 80 deg. beyond the Pole on to the Fourth Quadrant. Perhaps the loftiest range on the limb. Madler's measures give more than 27,000 feet as the height of one peak, and there are several others nearly as high.

FOURTH QUADRANT.

The Altai Mountains. A fine conspicuous serpentine range, extending from the E. side of Piccolomini in a north-easterly direction to the region between Tacitus and Catherina, a length of about 275 miles. The loftiest peak is over 13,000 feet. The average height of the southern portion is about 6000 feet. The region lying on the S.E. of this range is a vast tableland, devoid of prominent objects, rising gradually towards the mountains, which shelve rapidly down to an equally barren expanse on the N.W.

The Pyrenees. These mountains, on the E. of Guttemberg, border the western side of the Mare Nectaris. Their loftiest peak, rising nearly to 12,000 feet, is on the S.E. of Guttemberg.

LIST OF THE PRINCIPAL RAY-SYSTEMS, LIGHT-SURROUNDED CRATERS, AND LIGHT- SPOTS.

FIRST QUADRANT.

Autolycus. Encircled by a delicate nimbus, throwing out four or five prominent rays extending towards Archimedes. Seen best under evening illumination.

Aristillus. The centre of a noteworthy system of delicate rays extending W. towards the Caucasus; and on the S. disappearing among the rays of Autolycus. They are traceable on the Mare Nubium near Kirch.

Theaetetus. A very brilliant group of little hills E. of this formation.

Eudoxus A. A light-surrounded crater W. of Eudoxus, with distinct long streaks, one of which extends to the S. wall of Aristoteles.

Aristoteles A. A light-surrounded crater in the Mare Frigoris, N.E. of Aristoteles.

Aratus. A very conspicuously brilliant crater in the Apennines, with a smaller light-surrounded crater W. of it.

Sulpicius Gallus. A light spot near.

Manilius. Surrounded by a light halo and streaks.

Taquet. Has a prominent nimbus, and indications of very delicate streaks.

Plinius A. Is surrounded by a well-marked halo.

Posidonius gamma. Among the hills E. of this formation a light spot resembling Linne, according to Schmidt. He first saw it in 1867, when it had a delicate black spot in the centre. Dr. Vogel observed and drew it in 1871 with the great refractor at Bothkamp. These observations were confirmed by Schmidt in 1875 with the 14-feet refractor at Berlin.

Littrow. A very bright light-spot with streaks, on the site of a little crater and well-known cleft E. of this ring-plain.

Romer. A light-surrounded mountain on the E.

Macrobius. Two light-surrounded craters on the E. of this formation, the more northerly being the brighter.

Cleomedes A. (On the floor.) Surrounded by a nimbus and rays. Large crater, A, on the E. has also a nimbus and rays.

Agrippa. Exhibits faint rays.

Godin. Exhibits faint rays.

Proclus. A well-known ray-centre, some of the rays prominent on part of the Mare Crisium.