430 M. Mitcheli—Satellites of Saturn. 
Art. LV.—WNotes on the Satellites of Saturn ; by MARIA 
MITCHELL. 
THE object glass of the telescope used in the observations 
- which follow is of twelve and one-third inches diameter. Its 
definition is good. 
The telescope is used in such observations as its very imper- 
fect mechanism will allow; these are observations of the con- 
recording the time of passage of the satellites over a fixed wire. 
n the course of these observations such different relative mag- 
aitides have been given to the small satellites, on different even- 
ings, as to lead to the suspicion that some of them are variable. 
he sparkle of Tethys and the grayish blue color of Rhea 
make it seem unlikely that small stars can have been taken for 
_ these two satellites; in the case of Enceladus and Dione mis- 
takes are more easily made; but the rapid motion of Enceladus 
a its identity. The most noticeable changes are 
in Rhea. 
In 1877, Rhea is recorded as small on Nov. 30th; as dull 
on Dec. 3d; as blurry and large, Dec. 14th; and as ruddy, Dec 
18th. In 1878 Rhea is recorded as faint Oct. 3d and Oct. 16th ; 
as bright on Oct. 25th, and on Dec. 3d it is called nearly as 
bright as Titan. 
1877, Oct. 5.—Rhea was in ee with the preceding 
edge of the ring at 8" 58" 295 p.m. Two small satellites follow- 
ing the planet were in éinifahetioh at the same time; the smaller 
one sangha ti ag | ee the ball. 
1877, O —Two small satellites were rennet in conjunction 
with the acta of the preecding ring at 9" 28" p.m. The smaller 
of ann was gees Dione; the — may have been a sa 
877, Oct. 9.—10" 8™ Pp, u. Tethys is movin away from th 
ball and bas as passed soujeaction: with the ring. Another tatige; 
probably Enceladus, is coming in, and is nearly up to conjunction 
with the following edge of the rin 
1877, Oct. 13.—At 10 P. M., two small satellites were seen to be 
nearly together following Saturn, the space between them being 
bide sie 10" 53™ 31%, the two satellites could not be composer with 
a power of 400. The two were of the same size. At 11" 20” 31%, 
the staliises could be seen separated. These may be Tethys near 
greatest elongation, and Enceladus approaching the planet. 
1877, Oct. 14.—Rhea was in conjunction with the preceding 
_ of the ring and above the ring at 9° 9™ 30°, 
1877, Oct. 23.—Rhea was again in i poe with the preced- 
ing edge of the rin g and above it, at 10" 2 
