337 
Brightness of the Satellites of Jupiter. 
The sd is less than the ist. 
The 3d is larger than the 4th. 
July 31, 1794. i7 h 18' 38". 10-feet reflector; power 170, 
The four satellites of Jupiter are very favourably placed for my 
purpose. 
The 1st is less bright than the 2d ; it is a very little larger 
than the 2d : the difference in the size is but barely visible. 
The light of the 2d is very intense and white. 
The light of the 3d is very intense and bright. 
The light of the 4th is dull ; and seems to be inferior to the 
usual proportion it bears to the other satellites. 
i8 h 38' 38". With 300. 
The 4th satellite is larger than the 1st. 
The 2d satellite is a little larger than the 1st, or at least 
equal to it. 
The 3d is undoubtedly the largest. The order of the mag- 
nitudes therefore is, 3 4 2 1. 
My Brother, Alexander Herschel, looked at the satellites, 
and estimated the order of their magnitudes exactly the same; 
though he was not present when I made the foregoing esti- 
mations. 
August 1, 1794. i 7 h 38' 37". 10-feet reflector; power 170. 
The light of all the four satellites is very brilliant, the evening 
being very fine. 
With 300. 
The northmost and farthest of the two satellites which are 
in conjunction, is the smallest : I suppose it to be the 2d. 
