Rotation of the Ring of Saturn. 4^ 
that many of the observations are fuch as would alfo agree with 
other affignable periods, efpecially when the numbers of fpots 
is lo confiderable as five ; but the rnoft material obfervations 9 
which are thofe on the fpot a v fetting afide all the reft, feem 
alone to amount to a proof not only of a rotation of the ring* 
but of the time in which it is performed. 
( 
It may be expected, that having now fufficiently examined 
the whole feries of obfervations of the laft new fatellites, we 
oa 1 give then peiiochcal times and diftances more accurately 
than before. The times, indeed, are full as well afcertained 
as we can expeft to have them : for on calculating fix fatellites 
by my tables back to Aug. 19 d. 12 h. 19' 56", 1787, we find 
their places 341°, 1 the 5th; ro\6 the 4th ; 211°, 1 the 3d ; 
1 58', 9 the 2d; 8 o °, 2 the n't; and 288’, 8 the 6th. And 
journal contains the fulleft aflbrance that they were thus 
lituated at the time for which this calculation is made. We 
ma y therefore fix the period of the fixth at x d. 8 h. 8 // ,p 
The 7th fatellite can only be traced back as far as the 8th of 
Sept. 1789; fo that its revolution will require at leaf! ano- 
ther leafon to come to forne degree of accuracy, till when we 
fhall ftate it at 22 h. 3 7' 22", 9. 
The difiance of thefe fatellites, N deduced from calculation, 
depends intirely upon the time and diftance of the 4th, which 
is the fatellite that has been ufed. In order to obtain more 
accuracy m thefe elements, I have applied myfelf to mea- 
ning the difiance of the 4th fatellite in thofe moments which 
were moft favourable for the purpofe. It is well known that 
this fubjetl, on account of the quantity of matter in Saturn, 
to be deduced from the periodical times and diftances of the 
fatellites, is of confiderable importance to aftronomers ; I fhall 
7 therefore 
