( 404» > 
the i^th o( January at the fame hour in the morning, the tedu^ 
dtion of hours being made by the diffirence of the Meridims^ 
So that by the calcui he made, in fix years, of which one is z 
Btf fextile^ii is found to have made, in refpeft of the Earthy at 
leaft 5294 revolutions^each of 9 hours 55 minuteSjjS fecondsj, 
compcofacing one revolution by another^and at moft 5295 re- 
volutions of p hours,55 minutes,5 1 feconds5 forafmuch as he 
was aflured of the precifenefs of one Mean Revolution to one 
eight of a minute : which will be verified by future obfervati^ 
ons» Thus the Ephemerides were found ready made for the 
firft months of this prefent year, but only that we area little 
dijfFeiently to apply the Equations, that amount to forae mi« 
nutesjbecaufe that the diftance^ which J^^/^i^^i' now is at from 
the Sun and from his Apogee, is different from that, which he 
was at in the beginning of the year 1666 ; and that in this pre« 
fent year after the month of February^thzt day is to be counted 
which hath been added for the The Obfervations^ 
which SignorC/jj^i hath continued. to make fince the i^th of 
January^ as far as the weather did permit, have alwaies beea 
found conform to thofe Ephemerides. 
Uatil then he had never yet feen an immediate return of this 
Spot after 9 hours and $6 minutes, becaufe it had not hapned, 
that Ja^i^^r after the apparition of the Spot had itay'dj in one 
and the fame nighr^iong enough above the Horizon,at leaft at 
a (ufEcient height to obferve him with due diflinftnefs* He 
had only concluded the time of this revolution by returns ob- 
ferved after about ao^go^and 50 hours ; and he had more pre- 
cifely limited it by obfervations m3re diftaoc^But the night af- 
ter the I day of Mareh^^tj\ a clock in the evening^he faw this 
Spot in the midft of the Belt 3 and the fame nighljat 5 a clock 
and 26 minutes in the morning, he faw it agiin returned pre* 
cifely to the fame place. N^xt day he made a report of thefe 
ObktvniQmtothcR.Jcademy of ihe Sciences^ and predifted^ 
that the Spot woul(| arrive again at the raidfl of the Belt March 
5^ at 9 a clock and 8 minutes atnight^whereupon that Affem- 
b!y deputed M.Buot and Mariotte to be prefent at the Ob- 
fervations who being come to the J^. Obfervatory began to 
fee at 8 a clock and 4 minutes the Spot already fomewhat re- 
moved from the Oriejital limb^but yet obfcare and fmall. Ac 
8 a clock and 47 minutes they faw it very diftinftly advancing 
Pppp 2 towards 
