. Saturn'sRing.

Annual

Motion.

Diurnal

Motion.

The INTRODUCTION:

Besides these Attendants, Saturn is en*compassed with a thin plain Ring that doesno where touch his Body: The Diameter ofthis Ring is to the Diameter of Saturn asg to 4; and the void Space between theRing and the Body of Saturn is equal tothe Breadth of the Ring itself; so that in'some Situations the Heavens may be seenbetween the Ring and his Body. This sur-prising Phenomenon of Saturn' s Ring is amodern*Discovery; neither were the Satel-lites of Jupiter and Saturn known to theAncients. The Jovial Planets were firstdiscovered by the famous Italian Philoso-pher Galilaus , by a Telescope which hefirst invented: And the celebrated CaJJini ,the French King’s Astronomer, was the firstthat saw all the Satellites of Saturn ; whichby reason of their great Distances from theSun, and the Smallness of their own Bodies,cannot be seen by us, but by the Help ofvery good Glasses.

The Motion of the primary Planets roundthe Sun (as also of the Satellites roundtheir respective Primaries) is called theirAnnual Motion ; because they have oneYear or Alteration of Seasons compleat inone of these Revolutions. Besides thisAnnual Motion, four of the Planets, viz.Venus , the Earth, Mars and Jupiter re-volve about their own Axes, from Wejl jto Eajl ; and. this is called their Diurnal |

Motion.