( 40# f 
rfie ip/iS pfj^^fiWT^ in t&e mornings tBe reiJtsi 
j^ion of hours being made by the difference of the Meridimf^ 
So that by the calcul he rnadej in fix years, of which one is a 
^2/^/^;v^^/^>it is fotjfld to made, ia refpefl: of the Earthy ar 
leaft S294 revolucionsjeach of 9 hours 55 minutes^jS feconds^ 
Gompenfatingone revolution by another^and at moft 5295 re- 
volutions of 5> hours,5 5minutes,5 1 fecondsj^ fpraftnuch as ha 
was^afluredof theprecileneft ofone Revolutioa jta one 
eighc of a minute : which will be verified by future obleryati? 
ons* Thus the Ephemrides were found rpdy made for the 
firft months of this prefect yearj but only that we area little 
differently to apply the Equations, that amount to fome mu 
BUteSjbecaufe that the diftance, which Jupiter now is at from 
the Sun and from his Apogeeg is different frona that, which he 
was at in the beginning of the year 1666 ; and that in this pre- 
lent year after the month of fV^r a^r y,that day is to be counted 
which hath been added for the The ObfervationSj, 
which Signor(7<3!^«2 hath continued to make fince the iph oi 
January^ as far as the weather did permit, have alwaips beea 
found conform to thofe E^^^i^^ri^^/. 
Until then he had never yet feen zw immsdiate return of this 
Spot after 9 hours and yS minutes, becaufe it had not hapned, 
that Jupker after the apparition of the Spot had ftay'd, in ona 
and the fame night-long enough above the HorizoD,at leafi ae 
afufEcient height to obferve him with due difl:in£^n.efs4. He 
had only concluded the time of this revolution by returns ol> 
ferved after about 205303and 50 hours ; and he had more pre* 
cilely limited it by observations more diftanc*But the night af- 
ter the ! day of M^:jr^^5 at 7~ a clock in the evening^e faw thif 
Spot in the mid ft of the Belt 3 and the fame nigh t^at 5 a clock 
2nd 26 minutes in the mprning, he faw it again returned pre* 
cifely to the (ariie place. Next daybe made a report of theib 
Obfervations ioth^R. Academy of th ScknctSy and predifted, 
that the Spot woul(| arrive again at the midft of the Belt March 
5^ at 9 a clock and 8 rninutes arnightjWhereupoo that Aflferu- 
bly deputed M.Bmt and M» Mariotte to be prefent at th€ Ob- 
fervatioui who being come to the Ohjermtor/ began to 
fee at S g^ clock and 4 minutes the Spot already ib^ 
moved from the Oriental limb^but yet ©bfcure and ftnalL At 
8 a clock and 47 minutes they faw it very diftinftly advancing 
Ppp p 2 toward! 
