408 Prof. Loomis on the Satellites of Uranus. 
There are five instances in which Herschel observed what he 
Called “an exterior satellite.”? These observations are as follows: 
| M’n time. Position. Remarks. 
1790 Feb. 9.) 92 19” ode 8. or Ae About twice the — od ope parr: beri 
1791 Jan. $1./11 5 78 istance of the 
1792 Feb. 26,11 380 eS oy the ane At double the distance of the firs 
1796 March 5/10 53 |72 n.p. or 342 [Its distance ex st d that of the caida 
1798 Feb. 11.111 46 {89 nf. or 1 {Excessively fai 
These observations are all tolerably well Fig: by sup- 
posing a daily motion of 9°-6596, corresponding to a period of 
37-2686 days. The period which Herschel assigned to this sat- 
ellite is 38-075 days; but this period was derived from the com- 
puted distance of the satellite, and not from any estimate of the 
number . em performed in the interval between the 
observatior 
There are 6 font instances in which Herschel observed what he 
pe “the most distant satellite.” 'These observations are as 
oll 
M’n time. | Remarks. | 
1794 Feb. 28) 81 15” ae : re or a8 
1794 March27J11 19 (Sout Only ae glimpses. 
tata Near, its — About four times the distance of the 
1197 mee 86 north’n? elong’n. — ponciv 
1798 Feb. 16.)11 12 (83 s. p. or 187 '\Near its createst southern elongation. 
I am unable to reconcile the second of these observations with 
the others upon the supposition of any period approaching to that 
which Herschel assigned, viz., 107 days. Moreover the observa- 
tion appears very uncertain, for Herschel only professed to have 
“lucid glimpses of two stars at a good distance.’ The other 
ree observations are very well represented by a mean motion of 
3°-91305, corresponding to a period of 91-9998 days. 
In one instance, March 26, 1794, Hershel saw what he has 
ealled ‘an < vies satellite, » and he thought he caught a 
glimpse of the same object again on the 27th; but without fur- 
ther per res we can form no definite judgment of its period. 
The following are the final results for Lassell’s two satellites, 
and the two brighter satellites discovered by Herschel. The 
periods of the two latter were determined by Littrow, but the 
mean distances have been slightly corrected to make them accord 
with the pesiods of revolution. The elements of the two outer 
satellites are rudely determined from Herschel’s observations. 
Satellite. Period. 
Daily motion, Mean distance. —__ 
d. ae 
1 252049 142-829 IS37 
2 41 ok 86612 18°62 
3 8705886 41°35117 80°55 
4, 13°463263 26°73928 40°86 
6. 37-2686 ? 9°6596 ? 80-56 ? 
eh 6. 91:9998? . 391305? 147-132 
