PLANET SATURN". 391 



6^ degrees in the course of each revolution, bnt that 

 moreover in the shape of this planet there is an additional 

 deviation from the usual spheroidical figure arising from 

 the attraction of the ring, we may reasonably expect 

 that our present telescopes will enable us to observe a 

 visible alteration in its appearance, especially as our at- 

 tention is now drawn io this circumstance. 



In the year 1789 I ascertained the proportion of the Equatorial and 

 equatorial to the polar diameter of Saturn to be 22,81 polar dlam. of 

 to 20,61 *, and in this measure was undoubtedly included ' 



the effect of the ring on the figure of the planet, though 

 its influence had not been investigated by direct observa- 

 tion. The rotation of the planet wa's determined after- 

 wards by changes observed in the configuration of the 

 belts, and proper figures to represent the different situa- 

 tion of the spots in these belts were delineated +. In 

 drawing them it was understood that the shape of the 

 planet was not the subject of my consideration, and that 

 t'onsequently a circular disk, which may be described 

 without trouble, would be sufficient to show the configu- 

 rations of the changeable belts. 



Those who compare these figures, and others I hav6 Figure of Sa- 

 occasionally given, in which the particular shape of the *"^^* 

 body of the planet was not intended to be represented, 

 with the figure which is contained in my last paper, of 

 Avhich the sole purpose was to express that figure, and 

 wonder at the great difference, have probably not read 

 the measures I have given of the equatorial and polar 

 diameters of this planet ; and as it may be some satisfac- 

 tion to compare the appearance of Saturn in 1789 with 

 the critical examination of it in 1805, I have now drawn - 

 them from the two papers which treat of the subject; 

 Fig. 3. Plate I. represents the spheroidical form of the 

 planet as observed in 1789, at which time the singularity 

 of the shape since discovered was unknown ; and Fig. 4. 

 represents the same as it appear'sd the 5th of May 1 805. 

 The equatorial and polar diameters that were established . * 



in 1789 are strictly preserved in both figures, and the last 

 differs from the first only in having the flattening at the 



* PhiL Trans, for 1 790, p- 17. f Ibid, for 179a, p. 2%. 



G G g 2 poles 



