282 REPORT — 1872. 



1871, March 3. — Mr. Gledhill recorded the floor as dark, =0-66 ; the streaks 

 bright. Mr. Pratt recorded the floor as medium, =0-50. This evening he 

 witnessed an unusual display of streaks, as many as fifteen, which he arranged 

 in order of brightness thus : — the sector, the curved streak k near the north 

 border, the streak /3 from the triple group of spots Nos. 3, 30, and 31, the 

 streak a from spot No. 19 to the N.E. border, the middle arm of the trident e, 

 the N.W. curved streak c, "Webb's elbow i, the eastern arm of the trident ^, 

 the N. bifurcation of the western arm ^ and the southern bifurcation 6, 

 the narrow streak from S.W. to N.E., n, very rarely seen, the short arm I of 

 the sector towards the S.E. also very rarely seen, the streak y from spot 

 No. 6, the streak r) from spot No. 4, and the neiv streak p from spot No. 5 to 

 spot No. 17 (this, Mr. Pratt remarked, was seen easily joining the eastern 

 arm of the trident and the sector from a point opposite to No. 5 to a point 

 closely south of No. 17; it was narrowed about the middle). The streaks /3, 

 a, and I were far brighter than in their normal state. 



1870, May 12. — Mr. GledhUl recorded the floor as dark, =0-06, and the 

 streaks bright. He does not mention the sector ; but from his remark that 

 all were seen, and Mr. Elger regarding it as " very bright," I have in- 

 serted it. 



1870, March 14. — Mr. Elger's record is as follows : — " The markings were 

 not well seen ; the eastern arm of the trident was the brightest, and could be 

 traced from the south rim of Plato to spot No. 1, passing to the west of spot 

 No. 5. The streak y was very plain ; the rest of the markings were veiy 

 faint and difiicult to make out." Mr. Elger further says : — " In spite of the 

 haziness of the sky, the markings and minute details of the northern part of 

 the 3Iare Imbriiim were seen with unusual distiuctness." [This is another 

 important testimony to the unequal visibility of objects, and would indicate 

 that the indistinctness of the markings on Plato was dependent upon some 

 agency more immediately connected with the moon itself.] About an hour 

 earher on the same evening Mr. Pratt observed Plato, and recoi'ded the mark- 

 ings as rather easily visible. He observed all he had seen before, which were 

 of almost the identical forms of 1869, November 15 (see interval 84 to 96 

 hours, a7iie, p. 281). He also recorded two bright streaks irom. Anaxar/oras, 

 which crossed the N.W. border, the streak c, and the N.W. arm of the 

 trident, and somewhat confused at fii'st sight the light-markings on the 

 floor (see ante, p. 280). 



1870, June 10. — Mr. Elger recorded the sector and the streak y as the 

 brightest markings ; tj and f3 were faint, especially r/ ; /3, though faint, could 

 be traced up to spot No. 3. The eastern portion of a was bright and well 

 defined ; the west portion had a hazy appearance, as, indeed, had the whole 

 of the N.W. portion of the floor. Mr. GledhUl described the streaks and 

 spots as bright, and seen as on June 9; he recorded the floor as dark, =0-66. 



1870, Eebruary 12. — Mr. Gledhill recorded the floor as " medium, but 

 nearer dark." I have registered it at 0-55. Streaks all seen, except the 

 two faint ones \ and jj. ; e, the middle arm of the trident, brighter than either 

 4" or S ; n very broad and bright ; /3 and y well seen ; rj not distinct near spot 

 No. 4, but bright near the border of Plato. 



1870, August 8. — Mr. Gledhill recorded the floor as rather dark, =0-70, 

 Streaks not very bright, but well seen. 



1869, December 15. — Mr. Elger writes: — "The markings on the floor 

 were much more distinct than on the 14th. The prongs of the trident (^, e, 

 e), the sector (6), a fan of light extending from spot No. 4 to the east rim (r/), 

 and the brush (/3), on which spot No. 32 is situated, are showu on fig. 13. 



