ON MAPPING THE SURFACE OF THE MOON. 279 



87. The low central range in Rhaeticus, the south part. 



88. The mountain-range on which IV A* ^ is opened. Tt is S of B. & M. 

 The dotted lines in areas IV A" and IV A^ indicate the west toot of this 

 mountain-range, the east requires to be determined. 



IV A^.— 103. A craterlet east of IVA^^^^; estimated 2''-0, mag. 0-12. 

 Not in Lohrmann, but shown by B. & M. 



104. A mountain on the plain IV A^ ^* shown very plainly by Lohrmann 

 on Sec. I., and mentioned in his text (p. 55) as Ipng in 0° 30' of west 

 long, and 5° 40' of south lat., direction north to south, estimated length 

 6"-33, breadth 3". It is inserted from Lohrmann's sections, but does not 

 appear on the photograjDh. 1864, July 24, I saw and sketched it. The in- 

 strument used was the Hartwell Equatoreal, power 118, the eyepiece being 

 furnished with a diaphragm having a narrow sUt, along which the object was 

 allowed to pass, or kept in position by the clock motion. 



105. A hiU between the south end of IV A^ '"* and IV A^47 . estimated 

 diameter l"-75. 



106. A hill between the north end of IV A^ 1"* and IV A^ *7 . estimated 

 diameter l"-75. 



These two hiUs which are not seen on the photograph, are from Lohrmann, 

 They are on his Sec. I., and mentioned in his text, p. 55. I saw and sketched 

 them 1864, July 24. 



107. A slight elevation in and rather west of the centre of IV A^', seen 

 with the Royal Society's achromatic, 4i-inch aperture, power 230, 1867, 

 March 15, 7" 40", G. M. T. 



108. A bright spot on the north part of the mountain IV A^"'. 



109. A bright spot on the north part of the mountain IV A^'^^. Both 

 spots were seen 1867, March 15, 7'' 45™, G. M. T., with the Royal Society's 

 achromatic, 4|-inch aperture, power 230. 



110. A moimtain between IV A^^'' and IV A^*'' in the east border of 

 Hipparchus. 



111. The south part of the mountain-range IV A* ^^. 



112. A craterlet near the south end of IV A* **^, IVA^''^; estimated 

 3"-5, mag. 0-21. Shown by Lohrmann, but not by B. & M. 



113. A craterlet S.E. of IV A^^ 12. estimated 2"-0, mag. 0-12. Not in 

 Lohrmann, but shown by B. & M. 



114. A depression N.E. of the north end of IV A^'^"; estimated length 

 S.W.-N.E. 4"-0. Neither in B. & M., nor in Lohrmann. 



IV A^ 103 aj,^ lY A? 1 10 to IV A? 1 14, excepting IV A^ 1 ", were first seen 

 by the author, 1867, April 11, with the Royal Society's 4|-inch aperture, 

 power 230. The positions are confirmed by the photograph, although the 

 objects are not sufficiently distinct in the photograph to be recognized inde- 

 pendently of observation with the telescope. 



Lines of Upheaval and Depression. 



The south border of IV A^ ^^ is in the prolongation of the line of upheaval 

 IV A?, W.N.W.-E.S.E. No. 6. 



IV A^ S.S.W.-N.N.E. No. 5.— IV A^ 18 ^^^ IVA^''^ are in continuation 

 of this Une, which forms a gentle curve convex to E.S.E. 



