1leſſe forcible and offenſive to the ſight, than that primary and
direct light of the Sun. And thus without trouble do we behold
the face of the Moon; which were it as a Glaſſe, it appearing to
us by reaſon of its vicinity, as big as the Sun it ſelf, its ſplendor
would be abſolutely intollerable, and would ſeem as if we beheld
another Sun.
direct light of the Sun. And thus without trouble do we behold
the face of the Moon; which were it as a Glaſſe, it appearing to
us by reaſon of its vicinity, as big as the Sun it ſelf, its ſplendor
would be abſolutely intollerable, and would ſeem as if we beheld
another Sun.
SALV. Aſcribe not, I beſeech you Sagredus, more to my
monſtration, than it produceth. I will oppoſe you with an inſtance,
which I ſee not well how you can eaſily reſolve. You inſiſt upon it
as a grand difference between the Moon and Glaſſe, that it emits
its reflection towards all parts equally, as doth the Wall;
as the Glaſſe caſts it upon one onely determinate place; and from
hence you conclude the Moon to be like to the Wall, and not to
the Glaſſe: But I muſt tell you, that that ſame Glaſſe caſts its
reflection on one place onely, becauſe its ſurface is flat, and the
reflex rayes being to depart at angles equal to thoſe of the rayes
of incidence, it muſt follow that from a plane or flat ſuperficies,
they do depart unitedly towards the ſame place; but in regard
that the ſuperficies of the Moon is not plain, but ſpherical, and
the incident rayes upon ſuch a ſuperficies, being to reflect
ſelves at angles equal to thoſe of the incidence towards all parts,
by means of the infinity of the inclinations which compoſe the
ſpherical ſuperficies, therefore the Moon may ſend forth its
on every way; and there is no neceſſity for its repercuſſion upon one
place onely, as that Glaſſe which is flat.
monſtration, than it produceth. I will oppoſe you with an inſtance,
which I ſee not well how you can eaſily reſolve. You inſiſt upon it
as a grand difference between the Moon and Glaſſe, that it emits
its reflection towards all parts equally, as doth the Wall;
as the Glaſſe caſts it upon one onely determinate place; and from
hence you conclude the Moon to be like to the Wall, and not to
the Glaſſe: But I muſt tell you, that that ſame Glaſſe caſts its
reflection on one place onely, becauſe its ſurface is flat, and the
reflex rayes being to depart at angles equal to thoſe of the rayes
of incidence, it muſt follow that from a plane or flat ſuperficies,
they do depart unitedly towards the ſame place; but in regard
that the ſuperficies of the Moon is not plain, but ſpherical, and
the incident rayes upon ſuch a ſuperficies, being to reflect
ſelves at angles equal to thoſe of the incidence towards all parts,
by means of the infinity of the inclinations which compoſe the
ſpherical ſuperficies, therefore the Moon may ſend forth its
on every way; and there is no neceſſity for its repercuſſion upon one
place onely, as that Glaſſe which is flat.
Flat
glaſſes caſt forth
the reflection
wards but one
place, but the
ſpherical every
way.
glaſſes caſt forth
the reflection
wards but one
place, but the
ſpherical every
way.
SIMPL. This is one of the very ſame objections, which I
tended to have made againſt him.
tended to have made againſt him.
SAGR. If this be one, you had need have more of them; yet
I tell you, that as to this firſt, it ſeems to me to make more
gainſt you, than for you.
I tell you, that as to this firſt, it ſeems to me to make more
gainſt you, than for you.
SIMPL. You have pronounced as a thing manifeſt, that the
ction made by that Wall, is as cleer and lucid as that which the
Moon ſends forth, and I eſteem it nothing in compariſon thereto.
“For, in this buſineſſe of the illumination, its requiſite to reſpect,
and to diſtinguiſh the Sphere of Activity; and who queſtions
but the Cœleſtial bodies have greater Spheres of activity, than
theſe our elementary, frail, and mortal ones? and that Wall,
finally, what elſe is it but a little obſcure Earth, unapt to
ſhine?”
ction made by that Wall, is as cleer and lucid as that which the
Moon ſends forth, and I eſteem it nothing in compariſon thereto.
“For, in this buſineſſe of the illumination, its requiſite to reſpect,
and to diſtinguiſh the Sphere of Activity; and who queſtions
but the Cœleſtial bodies have greater Spheres of activity, than
theſe our elementary, frail, and mortal ones? and that Wall,
finally, what elſe is it but a little obſcure Earth, unapt to
ſhine?”
The ſphere of
Activity greater
in the Cœleſtial
bodies than in
mentary.
Activity greater
in the Cœleſtial
bodies than in
mentary.
SAGR. And here alſo I believe, that you very much deceive your
felf. But I come to the firſt objection moved by Salviatus; and
I conſider, that to make a body appear unto us luminous, it
ficeth not that the rayes of the illuminating body fall upon it,
but it is moreover requiſite that the reflex rayes arrive to our
eye; as is manifeſtly ſeen in the example of that Glaſſe, upon
felf. But I come to the firſt objection moved by Salviatus; and
I conſider, that to make a body appear unto us luminous, it
ficeth not that the rayes of the illuminating body fall upon it,
but it is moreover requiſite that the reflex rayes arrive to our
eye; as is manifeſtly ſeen in the example of that Glaſſe, upon