itia_
having a regular termination or surface, and having a pretty strong
reflecting quality, the many small reflections become united to the naked
eye, and make a very pretty shining surface.

Thirdly, the reason of its hardness and brittleness seems evident, for
since all the watery or liquid substance that moistn'd and toughn'd those
_Interstitia_ of the more solid parts, are evaporated and remov'd, that
which is left behind becomes of the nature almost of a stone, which will
not at all, or very little, bend without a _divulsion_ or _solution_ of its
_continuity_.

It is not my design at present, to examine the use and _Mechanisme_ of
these parts of Wood, that being more proper to another Enquiry; but rather
to hint, that from this Experiment we may learn,

First, what is the cause of the blackness of many burnt bodies, which we
may find to be nothing else but this; that the heat of the fire agitating
and rarifying the waterish, transparent, and volatile water that is
contain'd in them, by the continuation of that action, does so totally
expel and drive away all that which before fill'd the pores, and was
dispers'd also through the solid mass of it, and thereby caus'd an
universal kind of transparency, that it not onely leaves all the pores
empty, but all the _Interstitia_ also so dry and _opacous_, and perhaps
also yet further perforated, that that light onely is reflected back which
falls upon the very outward edges of the pores, all they that enter into
the pores of the body, never returning, but being lost in it.

Now, that the Charring or coaling of a body is nothing else, may be easily
believ'd by one that shall consider the means of its production, which may
be done after this, or any such manner. The body to be charr'd or coal'd,
may be put into a _Crucible_, Pot, or any other Vessel that will endure to
be made red-hot in the fire without breaking, and then cover'd over with
Sand, so as no part of it be suffer'd to be open to the Air, then set into
a good fire, and there kept till the Sand has continu'd red hot for a
quarter, half, an hour or two, or more, according to the nature and bigness
of the body to be coal'd or charr'd, then taking it out of the fire, and
letting it stand till it be quite cold, the body may be taken out of the
Sand well charr'd and cleans'd of its waterish parts; but in the taking of
it out, care must be had that the Sand be very neer cold, for else, when it
comes into the free air