76. The difference between the Equatoreal and Polar diameters of Jupiter
is 6230 miles; for his equatoreal diameter is to his polar as 13 to 12.
So that his Poles are 3115 miles nearer his center than his Equator is.
This results from his quick motion round his Axis; for the fluids,
together with the light particles, which they can carry or wash away
with them, recede from the Poles which are at rest, towards the Equator
where the motion is quickest, until there be a sufficient number
accumulated to make up the deficiency of gravity occasioned by the
centrifugal force, which always arises from a quick motion round an
axis: and when the weight is made up so, as that all parts of the
surface press equally heavy toward the center, there is an
_equilibrium_, and the equatoreal parts rise no higher. Our Earth being
but a very small Planet, compared to Jupiter, and it’s motion on it’s
Axis being much slower, it is less flattened of course; for the
difference between it’s equatoreal and polar diameters is only as 230 to
229, or 35 miles.
[Sidenote: Place of his Nodes.]
77. Jupiter’s Orbit is 1 degree 20 minutes inclined to the Ecliptic. His
North Node is in the 7th degree of Cancer, and his South Node in the 7th
degree of Capricorn.
[Sidenote: Saturn.