The reason of which difference may probably be, that the charring of
Vegetables, being an operation quickly perform'd, and whilest the Wood is
sappy, the more solid parts may more easily shrink together, and contract
the pores or _interstitia_ between them, then in the rotten Wood, where
that natural juice seems onely to be wash'd away by _adventitious_ or
unnatural moisture; and so though the natural juice be wasted from between
the firm parts, yet those parts are kept asunder by the _adventitious_
moystures, and so by degrees settled in those postures.
And this I likewise found in the _petrify'd_ Wood, that the pores were
somewat bigger then those of _Charcoal_, each pore being neer upon half as
bigg again, but they did not bear that disproportion which is exprest in
the tenth _Scheme_, between the small specks or pores in the first Figure
(which representeth the pores of Coal or Wood charr'd) and the black spots
of the second Figure (which represent the like _Microscopical pores_ in the
_petrify'd_ Wood) for these last were drawn by a _Microscope_ that
magnify'd the object above six times more in Diameter then the _Microscope_
by which those pores of Coal were observ'd.
Now, though they were a little bigger, yet did they keep the exact figure
and order of the pores of Coals and of rotten Wood, which last also were
much of the same cize.
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