IRREGULARITY OF THE PLAKET SATURN. JQ1 



ing of the polar regions of this planet in the 40-feet teles- 



Cdpe, I ascribed it to the attractive matter in the ring$, and 



of its tendency to produce such an eiVe.ct we can have no 



doubt; but as another circumstance, which was also no-r Not wholly 



ticed, namely, an apparent small flattening of the equato- Jj^ttrartiS 



rial parts, cannot be explained on the same principles, I of the ring. 



wished to ascertain what physical cause might be assigned 



for this effect, and with a view to an investigation of this 



point, I have continued my observations^ The position of the 



ring, at the last appearance of the planet, however, proved 



to be quite unfavourable for the intended purpose; for the 



very parts, which I was desirous of inspecting, were covered 



by the passage of the ring over the disk of the planet iu 



front, or were projected on the ring, where it passed behind 



the body. 



In my attempts to pursue this object, I perceived a new Recent charge 

 irregularity in the Saturnian figure, which, I am perfectly as- m ,ts fi .8 ure » 

 sured, had no existence the last time I examined the planet, 

 and the following observations contain an account of it. 



Observations. 



.June 16, 1807. The two polar regions of Saturn are at The two poles 

 present of a very different apparent shape. The northern dlffer * 

 regions, as iu former observations, are flattened; but the 

 southern are more curved or bulged outwards. 



I asked my son John Herschel, who after me looked at 

 Saturn while 1 was writing down the above observation, if he 

 perceived, that there was a difference in the curvature of the 

 north and south pole; and if he did, to mark on a slate how 

 it appeared to him. When I examined the slate. I found 

 that he had exactly delineated the appearance I have de- 

 scribed. 



In a letter to a very intelligent astronomical friend*, who 1 



has one of my 7-feet reflectors, I requested the favour of 

 him to examine both the polar regions of Saturn, and to let 



\ See Phil. Trans, for 1805, p. 276 ; or Journal, vol. xiii, p. 8. 

 • Dr. Wilson of Hampstead, late Professor of Astronomy at Glasgow. 



me 



