r 84 ) 
confequently the Sanllitem Il^28*. 18' a prima Stella Aricns. 
The interval of time is 855 5 daies, p hours, 20 minutes; inwhich 
tht Satellite had made a certain number of Revolutions to the fixe 
Stars, andbefides 9K 25^ 28', or 295 degrees^ 28 min. whofe Qm^ 
flement to a Circle 64°. 3 2', is 2 daies, 20% 36! motion of the Sa* 
telllte^ according to Hngens.So that 8^58 daics,s^56' or 12457876 
minutes of time, is the time of fomc number of intire %^vo^Htlons ; 
and dividing that interval by 15 daies 22 hours, 39 minutes, or 
22P59 min. (the P^nWof H^/^^/;/) the Quotient 543 fliewes the 
number of and again dividing 12457876 min. by 543, 
the 22961 .f min. or 15 daies, 22^.41'. 61^ appears to be the true 
time of this •S^^^/Z/V's PmW, Hence the diurnal motion mil he 2i \ 
34'. 38". 18'", and the -^««//^/befides 22 Revolutions io\ 20^ 43'. 
Having made Tables to this Period, I found that in the j^pogaon Ob« 
fervationof//'/^gwthe5<«?^///>tf wasabove 3 degrees fafter than by 
my calculm^ and that in the three other Obfervations of my own be- 
ing likcwife in the fuperior part it was about 2* ^i^f^''^^^ flowetthan 
by the fame Calculation. Now •cis evident that thefe differences 
muft arife from fome Eccentricity in the Orhlte of this Satellite^ and 
that in Ultareh 1659, the jifocronlon (as I may call it,) was fome- 
where in the Oriental Semicircle^ and that in November 1 682 it was 
in thtWeftern Semicircle j and fuppofing the Apocronlon fixt, it muft 
necelfarily be between 95.23° 46^.and i is.28°. 18'. a la * r that be- 
ing the common part between thofe t\yo Semicircles: and becaufe 
the difference was greater in Hugen's ObCervation than in Mw, 
'cwill follow that the Llnea Apfdumy or tyipocronlon^O^owM be near- 
er to 9^ 23°. 46'. than to 1 28^ 18'. I will fuppofe io^22^oof 
a prima Stella Arletisj ^^which happens to be alfo the place of Saturn 
Equlnoxj) and the greatert aquation about 2i degrees. Upon the 
fcorc of this Inequality the mean motion of the Satellite will be found 
about 2®. 45» flower in 23i7/<«r/, or 7 min. in zjear^ whence I ftatc 
the ^;?»/#^/ motion lo^ 20°. 36' above 22 Revolutions ^ and the cot* 
reft Epocha for the laft day o£ December 1682 at Noon in the Merldl- 
anoiLondon^Kio^ 1 5^ <i ^ from which Elements 1 com- 
pofe the following T able. 
