( 683 ) 
Satellites that come to pafs conformable to the calculus of Cafjim^ 
and differ days and hours from the calculus and predidians made 
upon the hypotheses of GdiWt : Befidesihac there fhould happen 
a great many which do not happen according to the fy ftem of 
CAjJinu E.g. according co the hypothefis of GaliUi^ the fourth of 
the Satellites Ihou Id have more than 9© Eclipfes in a year , of the 
duration of three or four hours ; but according to the ry|i:em of 
Caffi^i^ the fame Sacellit will be three or four years without fufFer- 
ing any Eclipfe. Which proceeds from nothing but the falfe fci- 
tpationof the Orbs fuppofed byGaliUi; as the great difference 
of the time of the Eclipfes that happen depends from this , that 
neither Galilao nor the orher Aftronomers do feparatcfrom the 
proper motion of the Satellites the appearances which do be- 
fal it by that of Jupiter about the Sun. And therefore 'tis^ that 
they have taken for afimpleand equal motiona motion compound- 
ed of an equal and unequal ; whence they have flipped into an 
error about the Mean motions, which in progrefsof time hath fo 
increafcdjthat the Configurations drawn from their hypothefes for 
that time have aJmoft no likenefs at all with thofe that areob- 
ferved. 
Thefeold hypoihefes were therefore far off from ferving to find 
the Longitudes, as their Authors intended them ; fince it was im» 
poffible for them nor only toobferve theEcHpfesof the Satellites 
for fome years to the nearnefs of an hour, buceven to make us 
koowand diftinguifli at this time one Satellit from another, where- 
as by the Sy ftem of Signor CaJJini oxiQ {my predift for many years 
tocome the Eclipfes of the Satellites with as much prccifenefs, as^ 
thofe of the Sun and Moon by the Aftronomical Tables. 
Methodus direfta & Geonietrica, cu;as ope inveftigantur Aphelia, 
Eccentricitates, Propoitionefque orbium Planetarum primari- 
orum, abfque fuppofira^ asqualitate anguii motus, ad alterum 
Ellipfe»s focum, ab Aftronomis haflenus ufurpata. Auth, hd- 
mundo Hally Jun. e Golleglo Reginae Oxot^* 
M Otf^ Terra amuus per Eclipskam^ opticmmin^^UAUtatem 
ducit motlhmcaterornm pUnetarum^ Ajlronomu Copernica- 
nis nomine Parallaxees orbis notiffimAm\ qu^m quidem i»£qifalitatem^ 
ex oh fetv-^tionibm non mult k opera datum ^ methodi feque^tis hafm 
firmijjimum confiitm\ ubi prater cbfervata nihil aiiud fupfomtur^ 
quAtn qmd orbes Plmetarum ftnt Eilipfes^ qubdque Sol in foco ^omnium 
9rbihm cmmmiy fit conptutmy & derhiquty qmd temper a periodic 
(mgukrum 
