Royal Astronomical Society. 309 



• •' * Nov. 21. Very fine night. Enceladus was seen the instant 

 the object was brought into the field of the double-image micrometer, 

 power 435 ; and when the image was divided, the two points were 

 still distinctly visible ; proving that the telescope will show a lucid 

 point oi half the brightness of Enceladus. The dark shade [on the 

 ball] is occasionally seen divided by a bright and excessively narrow 

 line. The planet bears 460 very well. 



" ' Dec. 5. The ring is curiously broken into portions, which 

 look almost like small satellites. Occasionally the planet is very 

 well seen. 



" ' Dec. 20. The ring is obvious enough, but is broken, especially 

 on the following side. 



" ' Dec. 21. The ring is reduced to a very fine line, occasionally 

 appearing broken, but sometimes entire. The eastern arm is not 

 quite so bright as the western. 



" ' 1849, Jan. 6. The ring is scarcely ever visible, but occasion- 

 ally in the best moments it may be traced neaiiy or perhaps quite 

 to the extremity. But some portions of it are brighter than others.' 



" At this time the earth was elevated about half a degree to the 

 north above the plane of the ring ; the sun being about 1°*8 to the 

 south of that plane. On the 19th, the earth passed from the north- 

 ern to the southern side of the plane of the ring ; and the bright 

 surface became visible. Cloudy weather precluded observations till 

 the 22nd. 



" 'Jan. 22, 7^ 12"^. Titan is in contact with the southern side 

 of the following arm, and about two-thirds of its length from the 

 edge of the planet. The ring is bright, though narrow. It is very 

 much brighter in two places similarly situated on each arm ; and they 

 coincide with the extremities of the inner and outer ring.' 



" Titan was distinguishable from the brighter parts noticed when 

 observed at 7^ 12™. It afterwards came into coincidence with those 

 on the following arm as it moved along it." 



Remarks. 



" 1 . From the observations above detailed, it is obvious that when 

 the obscure side of the ring is turned towards the earth, it is not in- 

 visible with moderate optical power. It also appears that its visi- 

 bility diminished as the earth approached its plane, and its edge, con- 

 sequently, was turned directly towards us. This is proved by the 

 increased difficulty of seeing it with my refractor on Aug. 9, com- 

 pared with July 15 ; between which dates the minor axis of the ring 

 had considerably diminished; by its invisibility on Aug. 20 and 

 Sept. 1, when the earth was very nearly in the plane of the ring ; 

 and by the increasing facility with which it was observed between 

 Oct. 1 1 and the end of November, during which interval the minor 



460, and was easily watched nearly up to contact with the following arm 

 of the ring. Its distance from the planet's centre was measured with the 

 parallel-wire micrometer under slight illumination of the field. At 7" 16'" 

 30' G. M. T. the distance was 34"-40 by four observations. With 460 and 

 658 the two bright satellites of Uranus were steadily seen. 



