34° Dr. Herschel's Observations of the 
The brightness of the 3d satellite is not intense; its colour, 
however, is white, though not so white as the bright part of the 
planet. 
September 24, 179b. 20 h 55' 24". 10-feet reflector; power 
600. The 1st satellite of Jupiter is very bright, and of a white 
colour ; it is also very large. 
The 2d satellite is faint and bluish ; its light is not much 
brighter than that of the belt. 
The 3d satellite is pretty bright; its light is whitish. It 
seems to be comparatively less than it ought to be ; or rather, 
its apparent smallness is owing to the uncommon largeness of 
the 1st. 
The 1st satellite, with 200, compared to the 3d, is propor- 
tionally larger than I have seen it before. 
September 30, 179b. 2o h 8' 4". 10-feet reflector; power boo. 
The satellites of Jupiter are well defined, and the night ia 
beautiful. 
The 3d satellite, in proportion to the 1st, is much larger than 
it was September 24. I ascribe the change to an apparent dimi- 
nution of the 1st. 
20 h 30' 4" The 1st satellite is evidently less in proportion 
to the 3d, than it was September 24. 
The 2d satellite is considerably bright ; its light is whitish ; 
much brighter than the belt, but not so bright as the bright part 
of the disc. Its magnitude is less than that of the 4th ; but 
its light is considerably superior. 
The 3d satellite is remarkably well defined. Its light is con- 
siderably brighter than that of the belts. 
The magnitude of the 1st satellite exceeds that of the 2d, 
It is nearly equal to that of the 4th. 
