Now if Light be reflected, not by impinging on the solid parts of
Bodies, but by some other principle; it's probable that as many of its
Rays as impinge on the solid parts of Bodies are not reflected but
stifled and lost in the Bodies. For otherwise we must allow two sorts of
Reflexions. Should all the Rays be reflected which impinge on the
internal parts of clear Water or Crystal, those Substances would rather
have a cloudy Colour than a clear Transparency. To make Bodies look
black, it's necessary that many Rays be stopp'd, retained, and lost in
them; and it seems not probable that any Rays can be stopp'd and
stifled in them which do not impinge on their parts.
And hence we may understand that Bodies are much more rare and porous
than is commonly believed. Water is nineteen times lighter, and by
consequence nineteen times rarer than Gold; and Gold is so rare as very
readily and without the least opposition to transmit the magnetick
Effluvia, and easily to admit Quicksilver into its Pores, and to let
Water pass through it. For a concave Sphere of Gold filled with Water,
and solder'd up, has, upon pressing the Sphere with great force, let the
Water squeeze through it, and stand all over its outside in multitudes
of small Drops, like Dew, without bursting or cracking the Body of the
Gold, as I have been inform'd by an Eye witness. From all which we may
conclude, that Gold has more Pores than solid parts, and by consequence
that Water has above forty times more Pores than Parts. And he that
shall find out an Hypothesis, by which Water may be so rare, and yet not
be capable of compression by force, may doubtless by the same Hypothesis
make Gold, and Water, and all other Bodies, as much rarer as he pleases;
so that Light may find a ready passage through transparent Substances.
The Magnet acts upon Iron through all dense Bodies not magnetick nor red
hot, without any diminution of its Virtue; as for instance, through
Gold, Silver, Lead, Glass, Water. The gravitating Power of the Sun is
transmitted through the vast Bodies of the Planets without any
diminution, so as to act upon all their parts to their very centers
with the same Force and according to the same Laws, as if the part upon
which it acts were not surrounded with the Body of the Planet, The Rays
of Light, whether they be very small Bodies projected, or only Motion or
Force propagated, are moved in right Lines; and whenever a Ray of Light
is by any Obstacle turned out of its rectilinear way, it will never
return into the same rectilinear way, unless perhaps by very great
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