_MADAM,_
To discourse of the World and Stars, is more then I am able to do,
wanting the art of Astronomy and Geometry; wherefore passing by that
Chapter of your Author, I am come to that[1] wherein he treats of
Light, Heat and Colours; and to give you my opinion of Light, I say,
it is not the light of the Sun, that makes an Animal see, for we can
see inwardly in Dreams without the Suns light, but it is the sensitive
and rational Motions in the Eye and Brain that make such a figure as
Light; For if Light did press upon the Eye, according to your _Authors_
opinion, it might put the Eye into as much pain as Fire doth, when
it sticks its points into our skin or flesh. The same may be said of
Colours, for the sensitive motions make such a figure, which is such
a Colour, and such a Figure, which is such a Colour; Wherefore Light,
Heat and Colour, are not bare and bodiless qualities, but such figures
made by corporeal self-motions, and are as well real and corporeal
objects as other figures are; and when these figures change or alter,
it is onely that their motions alter, which may alter and change heat
into cold, and light into darkness, and black colour into white. But
by reason the motions of the Sun are so constant, as the motions of
any other kind of Creatures, it is no more subject to be altered then
all the World, unless Nature did it by the command of God; for though
the Parts of self-moving Matter be alterable, yet all are not altered;
and this is the reason, that the figure of Light in our eye and brain
is altered, as well as it is alterable, but not the real figure of the
Sun, neither doth the Sun enter our eyes; and as the Light of the Sun
is made or patterned in the eye, so is the light of Glow-worms-tails,
and Cats-eyes, that shine in the dark, made not by the Sun's, but their
own motions in their own parts; The like when we dream of Light, the
sensitive corporeal motions working inwardly, make the figure of light
on the inside of the eye, as they did pattern out the figure of light
on the outside of the eye when awake, and the objects before them; for
the sensitive motions of the eye pattern out the figure of the object
in the eye, and the rational motions make the same figure in their own
substance. But there is some difference between those figures that
perceive light, and those that are light themselves; for when we sleep,
there is made the figure of light, but not from a copy; but when the
eye seeth light, that figure is made from a copy of the real figure of
the Sun; but those lights which are inherent, as in Glow-worms-tails,
are original lights, in which is as much difference as between a Man
and his Picture; and as for the swiftness of the Motions of light, and
the violence of the Motions of fire, it is very probable they are so,
but they are a certain particular kind or sort of swift and violent
motions; neither will all sorts of swift and violent motions make fire
or light, as for example the swift and violent Circular motion of a
Whirlewind neither makes light nor fire; Neither is all fire light,
nor all light fire, for there is a sort of dead fire, as in Spices,
Spirits, Oyles, and the like; and several sorts of lights, which are
not hot, as the light which is made in Dreams, as also the inherent
lights in Glow-worms, Cats-eyes, Fish-bones, and the like; all which
several fires and lights are made by the self-moving matter and motions
distinguishable by their figures, for those Motions make such a figure
for the Suns light, such a figure for Glow-worms light, such a figure
for Cats-eyes light, and so some alteration in every sort of light;
The same for Fire, onely Fire-light is a mixt figure, as partly of the
figure of Fire, and partly of the figure of Light: Also Colours are
made after the like manner, _viz._ so many several Colours, so many
several Figures; and as these Figures are less or more different, so
are the Colours.
Thus, _Madam_, whosoever will study Nature, must consider the Figures
of every Creature, as well as their Motions, and must not make
abstractions of Motion and Figure from Matter, nor of Matter from
Motion and Figure, for they are inseparable, as being but one thing,
_viz._ Corporeal Figurative Motions; and whosoever conceives any of
them as abstract, will, in my opinion, very much erre; but men are apt
to make more difficulties and enforcements in nature then nature ever
knew. But to return to Light: There is no better argument to prove
that all objects of sight are figured in the Eye, by the sensitive,
voluntary or self-motions, without the pressure of objects, but that
not onely the pressure of light would hurt the tender Eye, but that
the eye doth not see all objects according to their Magnitude, but
sometimes bigger, sometimes less: as for example, when the eye looks
through a small passage, as a Perspective-glass, by reason of the
difficulty of seeing a body through a small hole, and the double
figure of the glass being convex and concave, the corporeal motions
use more force, by which the object is enlarged, like as a spark of
fire by force is dilated into a great fire, and a drop of water by
blowing into a bubble; so the corporeal motions do double and treble
their strength, making the Image of the object exceeding large in the
eye; for though the eye be contracted, yet the Image in the eye is
enlarged to a great extension; for the sensitive and rational matter is
extremely subtil, by reason it is extreamly pure, by which it hath more
means and ways of magnifying then the Perspective-glass. But I intend
to write more of this subject in my next, and so I break off here,
resting,
Madam,
_Your Faithful Friend_
_and Servant._
[1] _Ch._ 27.