Archimedes Texts

66
which being of a spherical figure, if its superficies were smooth, as
this paper, the parts of its hemisphere illuminated by the Sun,
which are towards its extremity, would receive much less light,
than the middle parts; the rays falling upon them most obliquely,
and upon these at right angles; whereupon at the time of full
Moon, when we see almost its whole Hemisphere illuminated, the
parts towards the midst, would shew themselves to us with more
splendor, than those others towards the circumference: which is
not so in effect. Now the face of the Moon being represented
to me full of indifferent high mountains, do not you see how their
tops and continuate ridges, being elevated above the convexity of
the perfect spherical superficies, come to be exposed to the view
of the Sun, and accommodated to receive its rays much less ob
liquely, and consequently to appear as luminous as the rest?

SAGR. All this I well perceive: and if there are such moun
tains, its true, the Sun will dart upon them much more directly
than it would do upon the inclination of a polite superficies: but
it is also true, that betwixt those mountains all the valleys would
become obscure, by reason of the vast shadows, which in that
time would be cast from the mountains, whereas the parts towards
the middle, though full of valleys and hills, by reason they have
the Sun elevated, would appear without shadow, and therefore
more lucid by far than the extreme parts, which are no less diffu
sed with shadow than light, and yet we can perceive no such diffe
rence.

SIMPL. I was ruminating upon the like difficulty.

SALV. How much readier is Simplicius to apprehend the ob
jections which favour the opinions of Aristotle, than their soluti
ons? I have a kind of suspition, that he strives also sometimes to
dissemble them; and in the present case, he being of himself able
to hit upon the doubt, which yet is very ingenious, I cannot be
lieve but that he also was advis'd of the answer; wherefore I will
attempt to wrest the same (as they say) out of his mouth. There
fore tell me, Simplicius, do you think there can be any shadow,
where the rays of the Sun do shine?

SIMPL. I believe, nay I am certain that there cannot; for that
it being the grand luminary, which with its rays driveth away dark
ness, it is impossible any tenebrosity should remain where it com
eth; moreover, we have the definition, that Tenebræ sunt priva
tio luminis.

SALV. Therefore the Sun, beholding the Earth, Moon or o
ther opacous body, never seeth any of its shady parts, it not ha
ving any other eyes to see with, save its rays, the conveyers of
light: and consequently, one standing in the Sun would never
see any thing of umbrage, forasmuch as his visive rays would ever