bid 
406 Prof. Loomis on the Satellites of Uranus. 
Finally in the ronan of 1851, Mr. Lassell succeeded in settling 
this vexed question. On ten different nights in the months of 
October, “pment and December, he saw simultaneously four 
satellites and recorded their positions. The intervals are so short 
as to enable us to identify each satellite without danger of mis- 
take. These satellites are the two brighter ones already men- 
tioned, and two interior ones whose periods are about two and 
four days respectively. * 
The following are Lassell’s observations of the peor satellite, 
which I shall call satellite A. 'The distances and angles of posi- 
tion were not measured with a micrometer, but estimated by the 
eye, generally from the measured positions and distances of the 
o brighter satellites. The ase RC? are copied from No. 
$12 of the Astronomische Nachrichte » 
Observations of Satellite A. 
Greenwich mean ‘tale. Position, Distance. } Greenwich meantime. | Position. | Distance. 
1847. Sept. 14567 | 350° 1851. Nov. 17-487 : 
: 27-408 326 A 186 
Nov. 6429 846 114 : 21°489 123 
1851. Oct. 24-437 163 22-483 332 
28°5 825 | 27-480 845 
30°479 $6 f° -10 Dec. 11°375 150 
Nov. 25 320 12 16-413 | 160 | 18/75 
12-437 832 
All the observations of 1851 are well represented by supposing 
a daily motion of 142°-76. The observations of 1847 indicate a 
daily motion of 1439-09. The observations of the two years 
taken independently me ig a daily motion of 1429-92. If with 
this daily motion we compute the movement from the observa- 
tion of Nov. 6, 1847 to that: ot Nov. 27, 1851, we shall find it to 
amount to 588 revolutions and 134 degrees. Supposin the num- 
ber of revolutions to have been exactly 588 we obtain a daily 
motion of 1429829, which corresponds to one revolution in 
2°52049 days. 
The following are Lassell’s observations of the second interior 
satellite, which I shall call satellite B. They are taken from No. 
812 of the Astronomische Nachrichten. 
Greenwich mean time. | Position. |Distance.| Greenwich mean time. {| Position. ‘Distance, 
184 48 1851. Noy. 12°437 
Nov. 126 |° 10” 17437 47 
1851. Oct. eh cl 354 185 316 
28°65 350 21-489 63 
30°479 169 22°483 329 i 
Noy. 2°65 2738 | 138 f° Dec. 16°413 i * ee 
All the observations of 1851 are well represented by supposing 
a daily motion of 86°-90. The observations of 1847 indicate 4 
— motion of 86°-39. The observations of both years taken 
pendently in indicate a saily.3 motion of 862-69. If with this 
