250 REPOET — 186G. 



Length of crest 8"-08. Position, second order, x 5, -0103 west of 



photograph. Not well shown by Lohrmann. 



This peak is a conspicuous object on the line of cliffs extending from tho 



east of Ptolemaeus past Herschel (III A^ ^), and the west rim of Reaumur 



to the S.W. end of the rill of Hyginus. See partial description in Notes 



on III A^. 



*6. A crater S.E. of Reaumur 8"-08, mag. 0-5. 

 In consequence of the position of objects being more to the east in area 

 rV A«, the west border only comes into IV A*. The crater is a conspicuous 

 object on the line of cliflfe noticed imder IV A" ^. 92 Lohrmann, Sec. I. 



*7. A crater between Reaumiu' and HaUey, also between Herschel 

 and Horrox. F of B. & M., 5"-71, mag. 0-34. Position second 

 order x 7, '0139 west of photograph. 

 This crater is placed by B. & M. and Lohrmann on the N.E. border of Hip- 

 parchus, which is figured both by B. & M. and Lohrmann, as a plain sur- 

 rounded by mountains (see ante, p. 248), 1867, Feb. 11, I found it, as figured 

 by B. & M. and Lohrmann, opened on a mountain. It is probable that a 

 mountainous connexion exists between Reaumur and IV A^^". 



8. The N.W. part of the line of cliffs from Ptcaumur to Herschel. 

 *9. The N.W. part of a plain west of Herschel, the W of Lohrmann, 

 Sect. L SeeIVA^24_ 

 **10. A crater-form depression south of Rha^ticus. 



This depression, which is a very conspicuous and well-marked object on the 

 photograph of February 22, 1858, is hardly if at all recognizable on B. & M.'s 

 map or Lohrmanu's, Sect. I. Its form is sufficiently remarkable to arrest 

 the attention. The southern part presents the appearance of a crater which 



is elongated, and contracted towards the north, from whence a valley IV A" ^^ 

 extends towards Rhaeticus. 



The south end of IV A* '" forms a somewhat high cliff, IV A* ^*, as com- 

 pared with its interior. The valley IV A* ^^ is excavated in this cliff; IV A* '^ 

 is more particularly described imder IV A" ^^^ 



The west border of Rha3ticus, and also that of IV A* '^, the cliffs passing 

 cast of Horrox and crossing Hipparchus with the formation IV A^ 2^, and the 



mountains continued as far as the crater IV A^ ^ on the east of Albategnius, 

 together form a line of cliffs mth gently sloping faces towards the west by 

 south. This line of cliffs comes out in the full moon as a " Ray" directed 

 towards Tycho. It is weU marked, and more or less continuous, although in 

 many places it suffers interruptions. 



11. The tract of low land surrounding IV A** discovered by W. R. 

 Birt, 1866, Nov. 14. 



It is principally at the time of sunrise that this tract is perceptible as a 

 depressed surface ; at other times, except that of sunset, it is scarcely if at 

 all distinguishable from the surface of Hipparchus. 



12. A somewhat wide valley between IV A* ^^ and IV A* ^^ on the line 

 of cliffs from IV A" ^ to IV A" '*'. The east and west sides rise into 

 eminences; IV A*''" on the east is immediately between IVA* '^ 

 and IV A" '^, its sloping sides forming respectively the east and west 

 interiors of the depressions adjoining. An attentive inspection will, 

 however, convince the observer that IV A* ^^ is a mountain eloping 



