by the most accomplish'd Mr. Evelin, my highly honoured friend, to be inserted and published among those excellent Observations wherewith his Sylva is replenish'd, and would therefore have been here omitted, had not the Figure of them, as they appear'd through the Microscope been before that engraven.
This Petrify'd substance resembled Wood, in that
First, all the parts of it seem'd not at all dislocated, or alter'd from their natural Position, whil'st they were Wood, but the whole piece retain'd the exact shape of Wood, having many of the conspicuous pores of wood still remaining pores, and shewing a manifest difference visible enough between the grain of the Wood and that of the bark, especially when any side of it was cut smooth and polite; for then it appear'd to have a very lovely grain, like that of some curious close Wood.
Next (it resembled Wood) in that all the smaller and (if I may so call those which are onely visible with a good magnifying Glass) Microscopical pores of it appear (both when the substance is cut and polish'd transversly and parallel to the pores of it) perfectly like the Microscopical pores of several kinds of Wood, especially like and equal to those of several sorts of rotten Wood which I have since observ'd, retaining both the shape, position and magnitude of such pores. It was differing from Wood:
First; in weight, being to common water as 314 to 1. whereas there are few of our English Woods, that when very dry are found to be full as heavie as water.
Secondly, in hardness, being very neer as hard as a Flint; and in some places of it also resembling the grain of a Flint: and, like it, it would very readily cut Glass, and would not without difficulty, especially in some parts of it, be scratch'd by a black hard Flint: It would also as readily strike fire against a Steel, or against a Flint, as any common Flint.
Thirdly, in the closeness of it, for though all the Microscopical pores of this petrify'd substance were very conspicuous in one position, yet by altering that position of the polish'd surface to the light, it was also manifest, that those pores appear'd darker then the rest of the body, onely because they were fill'd up with a more duskie substance, and not because they were hollow.
Fourthly, in its incombustibleness, in that it would not burn in the fire; nay, though I kept it a good while red-hot in the flame of a Lamp, made very intense by the blast of a small Pipe, and a large Charcoal, yet it seem'd not at all to have diminish'd its extension; but only I found it to have chang'd its colour, and to appear of a more dark and duskie brown colour; nor could I perceive that those parts which seem'd to have been Wood at first, were any thing wasted, but the parts appear'd as solid and close as before. It was further observable also, that as it did not consume like Wood, so neither did it crack and flie like a Flint, or such like hard Stone, nor was it long before it appear'd red-hot.
Fifthly, in its dissolubleness; for putting some drops of distill'd Vinegar upon the Stone, I found it presently to yield very many Bubbles, just like those which may be observ'd in spirit of Vinegar when it corrodes corals,
