C ) 
fmall Eccentricity in its Motion, and from the Ovd Fi- 
gure of Jupiter s Body5who{e quick diurnal Rotation has 
by its Fi3 Centrifuga dilated his EquinoftiaJ, and made 
hh Meridians much Elliptical^ (o as to be difcernabieby 
the Telefcope. Mr. Newton has lliewn that his PoJar 
. Diameter is to that of his Equinodtial as 4Ot0 4i nearly. 
But we may hope future Oblervations may fhew how to 
divide thofe compounded caufes of Error, and correft 
them; which Errors are exceeding fmall in comparifon 
of the fliort time that the Satellites have been difco- 
vered, and argue the Skill and Diligence of the defer- 
vedly Famous Author of thefe Tables, 
I had almoft forgot the Conftruftion of the Table , 
pag.i^y. (hewing the half continuance of theft Eclipfes: 
In this the Semidiameter of the fliadow of Jupiter is 
made by Cajfwi juft lo Degrees, and that of ih^ Satel- 
lite 30'; and the Satellites Afcending Node being fup- 
pofed in 1 5°- of Aquarius^ ^t the end of this Century, 
(that iSj J5'*- 20'. before the Perihelion o{ Jupiter ) it 
will thence follow, that Num. I. being 816 or 2102, 
Jupiter pafles the Modes of the Satellites Orb, and con- 
fequently thefe Eclipfes are Central, and of the greateft 
Duration. But Num. 1. being xij or 1481, the Sa» 
tellite pafles the fhadow with the greateft Obliquity , 
viz. x"^. 55' from the Center, whence the Semimora be- 
, comes of all the fliorteft. This Table is not however 
' fo nicely computed, but that it may admit of Corre- 
ftion in the Seconds^ if a finall part of a Minute were 
confiderable in this affair. 
The Tables of the other three Satellites not being fo 
perfed or exaft as thofe of the fir ft ^ having greater in- 
equalities, are here given in another form, requiring 
the affiftance of the Tables of Jupiter s proper motion. 
The Periods of their Revolutions to Jupiter's (hade are 
^ *jas follows : 
Ibv Q^q Feriod. 
