ot be understood and appreciated without the
most strenuous exertions of well-directed reason?

XLV. But our admiration is not limited to the objects here described.
What is most wonderful is that the world is so durable, and so
perfectly made for lasting that it is not to be impaired by time; for
all its parts tend equally to the centre, and are bound together by a
sort of chain, which surrounds the elements. This chain is nature,
which being diffused through the universe, and performing all things
with judgment and reason, attracts the extremities to the centre.

If, then, the world is round, and if on that account all its parts,
being of equal dimensions and relative proportions, mutually support
and are supported by one another, it must follow that as all the parts
incline to the centre (for that is the lowest place of a globe) there
is nothing whatever which can put a stop to that propensity in the case
of such great weights. For the same reason, though the sea is higher
than the earth, yet because it has the like tendency, it is collected
everywhere, equally concentres, and never overflows, and is never
wasted.

The air, which is contiguous, ascends by its lightness, but diffuses
itself through the whole; therefore it is by nature joined and united
to the sea, and at the same time borne by the same power towards the
heaven, by the thinness and heat of which it is so tempered as to be
made proper to supply life and wholesome air for the support of
animated beings. This is encompassed by the highest region of the
heavens, which is called the sky, which is joined to the extremity of
the air, but retains its own heat pure and unmixed.

XLVI. The stars have their revolutions in the sky, and are continued by
the tendency of all parts towards the centre. Their duration is
perpetuated by their form and figure, for they are round; which form,
as I think has been before observed, is the least liable to injury; and
as they are composed of fire, they are fed by the vapors which are
exhaled by the sun from the earth, the sea, and other waters; but when
these vapors have nourished and refreshed the stars, and the whole sky,
they are sent back to be exhaled again; so that very little is lost or
consumed by the fire of the stars and the flame of the sky. Hence we
Stoics conclude--which Panaetius[221] is said to have doubted of--that
the whole world at last would be consumed by a general conflagration,
when, all moisture being