288 



REPORT 1872. 



Plato, October 19, 1869.— Gledhill. 



Interval 156 to 168 hours. 

 1870, May 14. — Mr. Elger recorded the markings aU faint ; a and Webb's 

 elbow well seen. At the point of junction of a, e, and i (qy. position of spot 

 No. 19) the floor was very bright. Mr. Gledhill on the same evening re- 

 corded the floor as dark, =0-66. Streaks bright, sector and a the brightest; 

 elbow well seen ; A. and fx were not seen. 



1869, August 21.— See ante, p. 253. 



1870, December 7. — Mr. Elger recorded all the markings as faint, except 

 K and p. Mr. Gledhill recorded the floor as dark, = 0-G6. 



1870, September 9.— Mr. Elger recorded r) and i.i as very faint. 



1869, October 19. — Mr. Gledhill recorded the floor as dark as the south 

 part of Grimaldi ; it is registered as =0-70. Mr. Gledhill furnished the 

 annexed sketch of the streaks o, /3, r/, 

 and y, with the sector, unaccompanied 

 by any remarks ; it would appear from 

 this that the whole of the S.W. part of 

 the floor was in some way obscured (see 

 pp. 255 to 262). Mr. Pratt's remarks on 

 the same evening confirm this idea ; he 

 says, " Trident near spot No. 1 invisible, 

 only the ends of the arms detected with 

 difficulty." He also specifies the posi- 

 tions of the darh localities on the floor : 

 " darkest near m, i. e. the mountain on 

 the north border." [It was this locality 

 which in May 1870 was noticed to be very light, see pp. 273 and 277.] The 

 next darkest area was closely S.W. of B. and M.'s rock ^, next above it, 

 S.W. of spot No. 1, and the lightest of the dark spaces N.W. of the rock ^. 

 We have here four areas characterized by a darker tiut, the floor itself being 

 registered as more than ordinarily dark, one of the darker spaces being 

 accompanied by an obliteration of nearly the whole of the trident. The 

 localities of the darker areas are shown on the annexed engraving, containing 

 Mr. Gledhill's streaks. 



Summar I/. —Hun's altitude 39° 9'-2 to 39° 50'-5 ; tint of floor 0-65, as 

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

 arms of trident, also the N.E. streaks a, (i, y, ij not so frequent. 



Interval 168 hours to meridian passage. 



1870, April 15.— Mr. Gledhill recorded the floor as dark, =0-66. Of the 

 streaks seen, the sector and a and /3 are described as very bright. The same 

 evening Mr. Elger described the sector and y as the brightest markings on 

 the floor ; tj, /3, and trident very faint. The projecting arm (registered as c, 

 see ante, p. 286) observed on the 14th appeared brighter this evening, and 

 extended further towards the west arm of trident, which it almost touched 

 (compare with Mr. Gledhill's sketch on January 15, 1870, ante, p. 286) ; its 

 direction formed an obtuse angle with the direction of the west arm and with 

 the streak a ; the streak " o " absent. 



1871, March 6. — Mr. Gledhill recorded the floor as dark, =0-66. The 

 streaks and sector bright and well seen, the two fainter streaks \ and ^ in- 

 cluded. These streaks have been seen on seven occasions before meridian 

 passage. 



1870, June 13.— Mr. Gledhill recorded the floor as dark, = 0-66 ; the 

 streaks and spots bright, but not well seen. Mr. Gledhill has the following 



