VOL. LXXXII.] PHILOSOPHICAL TRANSACTIONS. 121 



entering into a discussion, the mind seems to revolt, even at first sight, against 

 an idea of the chaotic state in which so large a mass as the ring of Saturn must 

 needs be, if phenomena like these can be admitted. Nor ought we to indulge 

 a suspicion of this being a reality, unless repeated and well-confirmed observa- 

 tions had proved, beyond a doubt, that this ring was actually in so fluctuating a 

 condition. Let us therefore examine what facts we have to guide us in this 

 inquiry. 



After looking over all his observations on Saturn, since the year 1774 to the 

 present time, Dr. H. can find only 4 where any other black division on the ring 

 is mentioned than the one which he has constantly observed, and from which he 

 had deduced the actual division of the ring into 2 very unequal portions. These 

 observations are as follow: June ]Q, 1780, 10^ 15"' mean time. With a new 

 7-feet speculum, having an aperture of 6.4 inches, with also a much improved 

 small speculum, and a power of about 200. I see a second black list on the 

 ring of Saturn, close to the inner side, on the preceding arm of the ring. See 

 figures, pi. 2. June 20, 1780, lO*" 10™. I see the same double list on the 

 preceding side of the ring. June 21, 1780, lO'' l™. Small 20-feet, Newto- 

 nian reflector, power 200. I see the 2d black list on Saturn's ring. It is closer 

 to the inside than the other is to the outside; but it is only visible en the pre- 

 ceding side of the ring. See figure 4. June 26, 1780, g'' 34™. Small 20- 

 feet, Newtonian reflector ; aperture confined to 7 inches. The 2d black list, 

 on the preceding side of the ring of Saturn, is visible. June 2Q, 1780, lO** IQ™. 

 Saturn's belts are very clear. I see but one black list on the ring. The shadow 

 of the planet is visible on the side of the ring, as well as on the small northern 

 part that projects beyond the planet. See fig. 5. Nov. 21, 1791, O*' 28™ sid. 

 time. 40-feet reflector, power 370. There is no other black division visible on 

 the ring of Saturn, but the one near the outer edge. 



It must be confessed that Saturn was in the very best situation for viewing 

 the plane of the ring, when the first 4 observations were made; and that conse- 

 quently they may be considered as a strong evidence for another division. But hi- 

 therto Dr. H. had set them aside as wanting more confirmation, not only because 

 he could never perceive the same dark line on the following side of the ring as 

 well as on the preceding side; nor since he could not find it on the 29th of June, 

 178O, as seen above; but chiefly, because he had not been able, with any of his 

 best instruments, to see it again at all. We also find by the observation of the 

 21st of November, 179>3 which has been added, that the southern plane, as 

 yet, presents us with no other division than the capital one, which he had ob- 

 served these 13 years, on both sides of the ring. However, if the opening 

 should be very narrow, and the rings eccentric, it is possible that a dark line 

 might by this means become visible on one side only. Besides, these objects 



VOL. XVII. R 



