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XXIII. On the Satellites of the Planet Saturn , and the Rotation 
of its Ring on an Axis* By William Herfchel, LL,D* 
F. R. S. 
Read June 17, 1790. 
I N fny laft Paper on the Planet Saturn, the principal objed 
of which was to give an immediate account of the 
mo ft interefting phenomena that had occurred till the begin- 
ning of November, many things were left unnoticed for want 
of time to treat of them with fufficient. accuracy; but having 
now before me the whole feries of obfervations from the 18th 
of July till the 25th of December, 1789, I can enter into a 
proper examination, affifted by fuch neceflary calculations as 
then could not conveniently be made. 
One of the principal motives which have induced me to 
haften this inquiry, is the frequent appearance of protuberant 
and lucid points on the arms of the ring of Saturn. I have 
mentioned before that fuch phenomena had been refolved by 
the fituation of fatellites that put on thefe appearances ; but as 
my obfervations were continued near two months afterwards, 
and as I had from them correded the epochae of the old fatel- 
lites, and improved the tables of the new ones, I found that, 
befides many of thefe bright points which were completely 
accounted for by the calculated places of the fatellites, there 
were alfo many more mentioned in my journal that would not 
accord with the fituation of any of them. 
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