276 REPORT— 1872. 



the markings were easily traced ; those on the east side of the floor, y, >;, and 

 /3, were decidedly the brightest ; »j was represented by a blight fan-shaped 

 marking close under the east wall." [This is clearly the bright object de- 

 scribed by Mr. Gledhill under date March 23, 1870, 36 to 24 hours (see post, 

 p. 296), before sunset on Plato; and it is evident that it retained the qua- 

 lity, whatever it may have been, which contributed to its bright appearance 

 during the intervening night. This quality appears to have affected the 

 whole of the northern part of the floor ; for we find, 36 to 24 hours before 

 the previous sunset, the streak a described by Mr. Gledhill as " diffuse and 

 extending up to the north border, and the following forenoon it could not be 

 seen as a distinct sharp streak." — "VV. E. B.] Mr. Elger described the streaks 

 a and " o " (seen as one) as ill-defined, especially the N.W. portion of it. 

 The eastern and middle arms of the trident were the only streaks seen on 

 the S.W. Mr. Gledhill, same evening, gives on a diagram the positions of 

 the sector and streaks more or less similar to those given by Mr. Elger, and 

 they both agi'ee in placing spot No. 5 on the east edge of f . Mr. Gledhill 

 describes all streaks as faint, and S and 6 (query e), on tinted plate in. 

 ' Student,' p. 161, as meeting at a point two thirds the distance from the 

 west border to spot No. 1. The east edge of sector is described as cutting 

 the S.E. border a little west of the middle of the straight part of the S.E. 

 border, and the west edge of sector cuts the south border nearly in the 

 middle. Mr. GledhiU says, " the brightest part of the floor is the north and 

 north-west, near the north border." a was not seen as a distinct sharp streak. 

 " If," says Mr. Gledhill, " the east edge of the sector be produced to the 

 north border, the darkest part of the floor lies to the east of this line. Is 

 not this the line of fault marked in your key-plan (Report Brit. Assoc. 1861, 

 p. 183) some years ago ? and is not this the portion seen brightest near 

 sunset at Plato on March 24, 1870 ? " Mr. Gledhill noticed that the most 

 southern-pointed shadow (a blunt cone) from the west border was situated 

 on and in the line of the streak 61 (query e). He does not mention the bright 

 part of T) seen by Mr. Elger, but gives the entire streak from spot No.- 4. 



1870, July 7. — Mr. Neison recorded the floor as dark, =0*66; he says, 

 " Never saw the floor so dark ; spots very indistinct, not visible continuously." 

 This is remarkable at so early an epoch, when the floor is generally described 

 as light or bright. It is also remarkable that the spots should have been 

 indistinct with so dark a floor. Mr, Elger remarked that the sector could 

 just be traced. 



1870, January 11, 5.36.— Mr. Gledhill records the floor as bright, =0-33. 



Determination of the position of sector. — See Report Brit. Assoc. 1871, pp. 

 i66 & 67, and ante, p. 249. 



Mr. Gledhill determined the S.E. extremity of the east edge of sector as 

 cutting the S.E. border nearly in the middle of the straight wall to the south 

 of II E ''' 2, and the south extremity of the west edge as cutting the south 

 border at a point characterized by a line through spots Nos. 3 and 17 pro- 

 duced to the south border, i. e. spots Nos. 3 and 17 and the south end of the 

 west edge of sector alicpi. [On comparing this alignment with the plan 

 from Mr. GledhiU's measurements (p. 66, Report 1871), it will be seen that 

 it does not agree with the plan. There is abundance of evidence to show 

 that the boundaries of the markings are variable in position. — W. R. B.] 



Mr. GledhiU recorded the sector as but little brighter than the floor ; in 

 the darker parts streaks a, j3, ij, y, ?, e, C were well seen. The N.W. part of 

 the floor was bright, and blended with the brightness of a. 7'' 0™. Streak 

 /3 extends a Httle towards the S.W. of spot No. 3 ; streak t; cannot be traced 



