Dr, Herschei/s Observations 
27S 
of their situation, which gives the latitude of the greatest cur- 
vature 45 0 21'. A second measure gives 45 0 41'. 
Jupiter being now at a considerable altitude, I have viewed 
it alternately with Saturn. The figure of the two planets is 
decidedly different. The flattening at the poles and ©n the 
equator of Saturn is much greater than it is on Jupiter, but the 
curvature at the latitude of from 40 to 48° on Jupiter is less 
than on Saturn. 
I repeated these alternate observations many times, and the 
oftener I compared the two planets together, the more striking 
was their different structure. 
May 2 6. 10-feet reflector. With a parallel thread micro- 
meter and a magnifying power of 400, 1 took two measures of 
the diameter of the points of greatest curvature. A mean of 
them gave 64,3 divisions = 11", 98. After this, I took also two 
measures of the equatorial diameter, and a mean of them gave 
60,5 divisions = if', 27 ; but the equatorial measures are pro- 
bably too small. 
To judge by a view of the planet, I should suppose the 
latitude of the greatest curvature to be less than 45 degrees. 
The eye will also distinguish the difference in the three dia- 
meters of Saturn. That which passes through the points of the 
greatest curvature is the largest ; the equatorial the next, and 
the polar diameter is the smallest. 
May 27. The evening being very favourable, I took again 
two measures of the diameter between the points of greatest 
curvature, a mean of which was 63,8 divisions = 11", 88. 
Two measures of the equatorial diameter gave 61,3 divisions 
= ii /, 5 44- 
