Archimedes Texts

64
solar rays come: but it is true that by the vivacity of the light, the
said image will appear fringed about with many rays, and so will
seem to occupie a far greater part of the plate, than really it doth.
And to shew that this is true, when you have noted the particular
place of the plate from whence the reflection cometh, and concei
ved likewise how great the shining place appeared to you, cover the
greater part of that same space, leaving it only visible about the
midst; and all this shall not any whit diminish the apparent splen
dor to one that beholds it from afar; but you shall see it largely
dispers'd upon the cloth or other matter, wherewith you covered
it. If therefore any one, by seeing from a good distance a small
gilt plate to be all over shining, should imagine that the same
would also even in a plate as broad as the Moon, he is no less de
ceived, than if he should believe the Moon to be no bigger than
the bottom of a tub. If again the plate were turn'd into a sphe
rical superficies, the reflection would be seen strong in but one sole
particle of it; but yet by reason of its liveliness, it will appear
fringed about with many glittering rays: the rest of the Ball would
appear according as it was burnished; and this also onely then

when it was not very much polished, for should it be perfectly
brightned, it would appear obscure. An example of this we
have dayly before our eyes in silver vessels, which whilst they are
only boyl'd in the Argol and Salt, they are all as white as snow, and
do not reflect any image; but if they be in any part burnish'd, they
become in that place presently obscure: and in them one may see the
representation of any thing as in Looking-glasses. And that chan
to obscurity, proceeds from nothing else but the smoothing and
plaining of a fine grain, which made the superficies of the silver
rough, and yet such, as that it reflected the light into all parts,
whereby it seemed from all parts equally illuminated: which
small unevennesses, when they come to be exquisitely plained by
the burnish, so that the reflection of the rays of incidence are all
directed unto one determinate place; then, from that same place,
the burnish'd part shall shew much more bright and shining than
the rest which is onely whitened by boyling; but from all other
places it looks very obscure. And note, that the diversity of

sights of looking upon burnish'd superficies, occasioneth such
difference in appearances, that to imitate and represent in picture,
v. g. a polish'd Cuirace, one must couple black plains with white,
one sideways to the other, in those parts of the arms where the
light falleth equally.

Some write what
they understand
not, and therefore
understand not
what they write.

Burnish'd Steel
beheld from one
place appears very
bright, and from
another, very ob
scure.

SAGR. If therefore these great Philosophers would acquiese
in granting, that the Moon, Venus and the other Planets, were not
of so bright and smooth a surface as a Looking-glass, but wanted
some small matter of it, namely, were as a silver plate, onely boyled