1which, without queſtion, the illuminating rayes of the Sun do
come; yet nevertheleſſe, it appears not to us bright and ſhining,
unleſſe we ſet our eye in that particular place, where the
ction arriveth. Now let us conſider what would ſucceed, were
the glaſſe of a ſpherical figure; for without doubt, we ſhould
find, that of the reflection made by the whole ſurface
ted, that to be but a very ſmall part, which arriveth to the eye
of a particular beholder; by reaſon that that is but an
rable particle of the whole ſpherical ſuperficies, the inclination
of which caſts the ray to the particular place of the eye; whence
the part of the ſpherical ſuperficies, which ſhews it ſelf ſhining
to the eye, muſt needs be very ſmall; all the reſt being
ſented obſcure. So that were the Moon ſmooth, as a
glaſſe, a very ſmall part would be ſeen by any particular eye to
be illuſtrated by the Sun, although its whole Hemiſphere were
poſed to the Suns rayes; and the reſt would appear to the eye of
the beholder as not illuminated, and therefore inviſible; and
finally, the whole Moon would be likewiſe inviſible, for ſo much
as that particle, whence the reflection ſhould come, by reaſon of
its ſmalneſſe and remoteneſſe, would be loſt. And as it would be
inviſible to the eye, ſo would it not afford any light; for it is
together impoſſible, that a bright body ſhould take away our
darkneſſe by its ſplendor, and we not to ſee it.
come; yet nevertheleſſe, it appears not to us bright and ſhining,
unleſſe we ſet our eye in that particular place, where the
ction arriveth. Now let us conſider what would ſucceed, were
the glaſſe of a ſpherical figure; for without doubt, we ſhould
find, that of the reflection made by the whole ſurface
ted, that to be but a very ſmall part, which arriveth to the eye
of a particular beholder; by reaſon that that is but an
rable particle of the whole ſpherical ſuperficies, the inclination
of which caſts the ray to the particular place of the eye; whence
the part of the ſpherical ſuperficies, which ſhews it ſelf ſhining
to the eye, muſt needs be very ſmall; all the reſt being
ſented obſcure. So that were the Moon ſmooth, as a
glaſſe, a very ſmall part would be ſeen by any particular eye to
be illuſtrated by the Sun, although its whole Hemiſphere were
poſed to the Suns rayes; and the reſt would appear to the eye of
the beholder as not illuminated, and therefore inviſible; and
finally, the whole Moon would be likewiſe inviſible, for ſo much
as that particle, whence the reflection ſhould come, by reaſon of
its ſmalneſſe and remoteneſſe, would be loſt. And as it would be
inviſible to the eye, ſo would it not afford any light; for it is
together impoſſible, that a bright body ſhould take away our
darkneſſe by its ſplendor, and we not to ſee it.
The Moon if it
were ſmooth, like a
ſpherical glaſſe,
would be inviſible.
were ſmooth, like a
ſpherical glaſſe,
would be inviſible.
SALV. Stay good Sagredus, for I ſee ſome emotions in
the face and eyes of Simplicius, which are to me as indices that
he is not either very apprehenſive of, or ſatisfied with this which
you, with admirable proof, and abſolute truth have ſpoken.
And yet I now call to mind, that I can by another experiment
remove all ſcruple. I have ſeen above in a Chamber, a great
ſpherical Looking-glaſſe; let us ſend for it hither, and whileſt it
is in bringing, let Simplicius return to conſider, how great the
clarity is which cometh to the Wall here, under the penthouſe,
from the reflection of the flat glaſſe.
the face and eyes of Simplicius, which are to me as indices that
he is not either very apprehenſive of, or ſatisfied with this which
you, with admirable proof, and abſolute truth have ſpoken.
And yet I now call to mind, that I can by another experiment
remove all ſcruple. I have ſeen above in a Chamber, a great
ſpherical Looking-glaſſe; let us ſend for it hither, and whileſt it
is in bringing, let Simplicius return to conſider, how great the
clarity is which cometh to the Wall here, under the penthouſe,
from the reflection of the flat glaſſe.
SIMPL. I ſee it is little leſſe ſhining, than if the Sun had
rectly beat upon it.
rectly beat upon it.
SALV. So indeed it is. Now tell me, if taking away that ſmall
flat glaſſe, we ſhould put that great ſpherical one in the ſame
place, what effect (think you) would its reflection have upon the
ſame Wall?
flat glaſſe, we ſhould put that great ſpherical one in the ſame
place, what effect (think you) would its reflection have upon the
ſame Wall?
SIMPL. I believe that it would eject upon it a far greater and
more diffuſed light.
more diffuſed light.
SALV. But if the illumination ſhould be nothing, or ſo
ſmall, that you would ſcarſe diſcern it, what would you ſay
then?
ſmall, that you would ſcarſe diſcern it, what would you ſay
then?
SIMPL. When I have ſeen the effect, I will bethink my ſelf
of an anſwer.
of an anſwer.