Rotation of the Ring of Saturn. 
As obfervations, carefully made, fhould always take the lead 
of theories, I fhall not be concerned if fuch lucid Ipots as I 
am now going to admit, fhould feem to contradidt what has 
been faid in my laft Paper, concerning the idea of inequalities, 
or protuberant points. We may however remark, that a lucid, 
and apparently protuberant point, may exift without any great 
inequality in the ring, A vivid light, for inftance, will feem to 
project greatly beyond the limits of the body upon which it is 
placed. If therefore the luminous places on the hop- fhould 
be fuch as proceed from very bright reflecting regions, or, 
which is more probable, owe their exigence to the more fluc- 
tuating caufes, of inherent fires adting with great violence, we 
need not imagine the ring of Saturn to be very uneven or 
diftorted, in order to prefent us with fuch appearances as will 
be related. In this fenfe of the word, then, we may ftill 0 p- 
pofe the idea of protuberant points, fuch as would denote- 
immenle mountains of elevated furface. 
On comparing together leveral obfervations, a few trials 
fhew that the brighteft and beft obferved fpot agrees to a revo- 
lution of io k 32" 15 ",4 ; and, calculating its diftance from 
the center of Saturn on a fuppofition of its being a fatellite, we 
find it ly ,227, which brings it upon the ring. It is there- 
fore certain, that unlefs we fhould imagine the ring to be fuffi- 
eiently fluid to permit a fatellite to revolve in it, or fuppofe a 
notch, groove, or divifion in the ring, to fuffer the fatellite to 
pafs along, we ought to admit a revolution of the ring itfelf. 
The denfity of the ring indeed may be fuppofed to be very 
inconfiderable by thofe who imagine its light to be rather the 
effedt of fome fhining fluid, like an aurora borealis, than a 
refledtion from fome permanent fubftance ; but its difapparition 
m general, and in my telefcopes its faintnefs when turned edge- 
ways,, 
j 
