264 REPORT— 1873. 



have been seen as a sharp narrow bright streak, from the tip of the most 

 northern shadow to the north-cast border nearly parallel with a line through 

 spots Nos. 1 and 4, and no mention of a bright floor in its neighbourhood. 



On December 15, interval 96 to 108 hours after sunrise, the continuation 

 " " was seen " fairly bright," but on the I7th it was not recorded ; a new 

 phase, however, was noticed, viz. Webb's elbow, which was continued in c, 

 terminating the streak recorded as very bright on the west. This phase was 

 more fully developed on April 14, 1870. The brightness of the streak con- 

 tinued from December 17 to December 24 ; indeed it was recorded as the 

 hriijhtest on December 21, 22, and 24. 



Lunation January 1870, from 36 Jiours after sunrise to 33 Jiours before 



meridian jyassage. 



On January 11, 1870, 36 to 48 hours after sunrise, the streak was well 

 seen, its brightness blending with the bright north-west floor. On the 12th, 

 14th, and 15th, the continuation " o " was observed. On the 15th, 132 to 

 144 hours after sunrise, the streak o, which extended from Webb's elbow, 

 tvas quite separated from the border. 



Lunation February 1S70, from 24 Jiours after sunrise to 69 hours before 



meridian passage. 



On February 9, interval 24 to 36 hours after sunrise, as remarked under 

 the December lunation, the streak was recorded as " sharp, narrow, and 

 bright." Either the streak must have been brighter than in December, as 

 seen during the same interval, or the floor darker; whichever of the two was 

 the real state, the difference is not explicable on a chai5ge of illuminating 

 angle, the altitude of the sun being the same both in December and February. 

 On February 11 and 12 the streak was well seen, being recorded as very 

 broad and bright on the 12th. 



Lunation March 1870, from meridian passage to 24 hours before sunset. 



The observations during this lunation were made under the reverse light, 

 i. e. after meridian passage. On the 17th and 19th of March the streak a 

 and the sector were the brightest markings on the floor. On the 23rd, under 

 a declining sun, the streak appeared diffuse and extending up to the north 

 border. This is remarkable, and indicative of the brightness not being due 

 to illuminating angle, which, from the slope towards the north-west border 

 being turned from the sun, would render the floor darlcr as seen by Mr. 

 Pratt on August 28, 1869, and by Mr. Gledhill on March 24 and Novem- 

 ber 15, 1870. (See Eeport Erit. Assoc. 1871, pp. 86, 87.) 



Lunation April 1870, from 36 hours after sunrise to 45 hou7-s after 



meridian passage. 



The principal feature in the earlier observations of this lunation is the 

 indcfinitencss of the continuation " o " which appears in Mr. Elger's sketch 

 of April 10 (see fig. 12, post, p. 275), but was not seen by Mr. Gledhill as a 

 distinct sharp streak on that day. On the 11th it was very hazy and ill- 

 defined. On April 14, interval 132 to 144 hours, the floor presented quite 

 a difiTerent aspect (see fig. lb, post, p. 285) to that of April 10, the continii- 

 ation " " being entirely absent, and the elongation of streak c towards the 

 Avestern arm of the trident e being concave towards the western border. On 

 the last occasion, November 19, interval 168 to 156 hours, when c extended 



