OBSERVATIONS OF LUNAR OBJECTS. 287 



the east of spot No. 3. The elbow on the N.W. border, just to the S.W. of 

 the end of the ridge which runs from the wall of Plato out to the N.W., is 

 well seen ; it sends out an arm to the south, which is forked. The northern 

 prong, which extends to the west border, is the extension ' o ' of the streak a, 

 and the southern prong c meets the streak h west of the point of j unction of 

 the streaks S and e.'' Mr. Gledhill further says, " I also see another faint 

 streak sent off from the long northern streak « up to the border ; it cuts the 

 border just east of the exterior ridge." [This faint streak is marked r ; it 

 has not been reobserved.] " A narrow faint streak runs from a point a little 

 to the S.W. of spot No. 3, parallel to a, and joins the streak S between its 

 junction with c and e " [this streak is marked \] ; " there is also a stUl 

 fainter and shorter streak (f.i) just south of a, or rather its continuation, " o." 

 I tried to see ft and the streak X as a continuous streak, but could not ; 

 neither did I find that they were cjuite in the same S.W. direction, but they 

 were very nearly so indeed. ?/ could not be traced quite up to spot No. 4 ; 

 on the border it was a large square bright streak resting against the foot of 

 the terrace (lowest) of the inner N.E. wall." 



The streaks \ and ^, discovered this evening, have been observed only 

 by Mr. Gledhill ; it is probable that they are too faint to be seen with 

 smaller apertures than 9 inches ; they have been seen occasionally between 

 January 15, 1870, and March 6, 1871. 



1869, August 20.— See ante, p. 2.53. 



1870, November 6. — Mr. Gledhill recorded the floor as dark, = 0*66 ; 

 streaks very bright. Mr. Elger says of them, " all faint and difficult to trace, 

 those on the east side of the floor especially." 



Summari/.— Una's altitude 36° 17'-5 to 37° 57'-8 ; tint of floor 0-62, esti- 

 mated from curve. Streaks generally visible — the sector, east and middle 

 arms of trident, and the N.E. streaks a, 0, y, and rj ; the whole variable in 

 brilliancy. On January 15 and May 13, 1870, more streaks were seen than 

 usual, especially on May 13. 



Interval 144 to 156 hours. 



1871, March 5. — Mr. Elger described the markings as all faint. 



1869, July 22. — Mr. Gledhill could see nothing on the floor, which he re- 

 corded as very dark. 



1870, August 10. — Mr. Neison recorded the floor as medium, = 0-50, and 

 Mr. Gledhill recorded it as dark,=0'66 ; he described the streaks as bright, 

 and t; not far from the border, as usual. 



1869, December 17. — Mr. Gledhill recorded the floor as dark,=0-66 : he 

 described the sector as bright, and streak a as very bright ; ft and y as bright, 

 c, €, and (J less bright, but not equally so ; tj the faintest, but bright near 

 the border of Plato. Mr. Gledhill describes a luminous broad patch, which, 

 starting from the inner border of Plato, about B. & M."s object e [the most 

 northern peak on the west border], joins the streak a ; it also sends off a 

 luminous streak to S. The luminous patch is brighest and broadest near the 

 foot of the inner slope. [The broad patch is most probably Webb's elbow, 

 and the streak to ^ is c. — W. U. B.] 



1870, October 8. — Mr. Elger recorded the markings as generally faint, 

 except a, Webb's elbow, and c. ft and y were much brighter than »; ; the 

 trident faint. 



Summary.— Snn's altitude 37° 57'-8 to 39° 9'-2 ; tint of floor 0-64, esti- 

 mated from curve. Streaks generally visible — sector, trident, and N.E. streaks ; 

 they alternated in brightness. 



