A natural history containing many not common observations extracted out of the best modern writers / by Sir Thomas Pope Blount, Baronet.

Observations concerning PETRIFI∣CATION.

OF PETRIFYING Waters, tho' I doubt not but their Kinds are as various, as the Effects they produce; and the Effects again, as the Subjects they Work on; yet I am inclin'd to believe, that they all agree thus far, that they proceed in the Main from the same Stock and Linage, and are all more or less of the Kindred of SALTS, which sublimed and rarified in the

Bowels of the Earth into an invisible Steam, are receiv'd by the Waters as their most agreeable Vehicle, and brought hither to us at the Rising of Springs, as invisibly as the Par∣ticles of Silver or Gold, when each is dissolved in its proper Menstruum: Where meeting perchance with an ambient Air, much colder and chil∣ling than any under Ground, in all likelyhood are precipitated, and thrown down on such Subjects, as they casually find at the place of their Exit, which they presently Cloath with a Crust of Stone; or else (where Precipitation or Cohesion will not suffice) they pass with the Waters through the Pores of the Subjects, and are left behind in them just as in a Filter.

The Reason of which difference may probably be, that some of these PETRIFYING Steams or Atoms, may be gross and more bulky, than some others are, and cannot be held up in the watry Vehicle, without such a Heat as they have under

Ground, but fall, and by Reason of their bigness, do not penetrate, but adhere to their Subjects; whereas others that are fine, more minute, and subtile, are easily supported in a Volatile Condition, and pass with the Waters into the closest Tex∣tures.

If any body doubt whether Stones, and so PETRIFICATIONS, arise from SALTS, let him but consult the Chymists, and ask whe∣ther they find not all indurated Bo∣dies, such as Stones, Bones, Shells, and the like, most highly sa••ed with the Saline Principle? Some Mixture of Earth and Sulphur, 'tis true, there is in them, which give the Opacity that most Stones have; from which, according as they ar•• more or less free, they have pro∣portionable Transparency, and some hardness too; as the best of Gems, the Diamant, evinces. And if he shall ask what SALTS are the apt∣est to perform this Feat of PETRI∣FICATION, though the diffic••lty

of the Question might well excuse me, yet I'll venture thus far to give him an Answer, That I have fre∣quently seen at Whitstable in Kent, how their Coperas or Vitriol is made out of Stones, that 'tis more than probable were first made out of That: To the Spirit of which Vi∣triol, if you add Oyl of Tartar, they presently turn into a fix'd and somewhat hard Substance, not much inferior or unlike to some Incru∣stations; which seems to conclude, that from these Two, all such like Concretions are probably made; and that could we but admit that Ocean of Tartar, which Plato plac'd in the Center of the Earth, and thought the Origin of all our Springs, the business of PETRIFICATIONS were sufficiently clear. To which I also add in the behalf of Vitriol, what's matter of Fact, and prevails with me much, That where-ever I find strong Vitriol-Waters, the PETRIFYING ones are seldom far off. PLOT's Nat. Hist. of OXFORD∣SHIRE.

The Ingenious, and Learned Mr. Hook saith, that all the PETRIFIED Pieces of Wood that he ever saw, seem'd to have been rotten Wood before the PETRIFICATION be∣gan. And since I have Named this Industrious and knowing Gentleman, I shall not think my time ill spent, if (for the Entertainment of the Reader) I Transcribe the Observa∣tions he hath made of a Piece of PETRIFIED Wood, taken from a Microscopical Examen.

This PETRIFY'D Substance re∣sembled Wood, in that

First, all the parts of it seem'd not at all dislocated, or alter'd from their Natural Position whiles they were Wood; but the whole Piece retain'd the exact shape of Wood, having many of the Con∣spicuous Pores of Wood still remain∣ing 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 appeared 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 only to be seen by a good Glass) Microscopical Pores of it appear, (both when the Substance is cut and polish'd Transversly, and Parallel to the Pores) perfectly like the Micro∣scopical Pores of several kinds of Wood, retaining both the shape, and Position of such Pores.

It was differing from Wood, First, in Weight, being to Com∣mon Water, as 3¼ to 1. Where∣as there are few of our English Woods, that, when dry, are found to be full as heavy as Wa∣ter.

Secondly, in Hardness, being very near as hard as a Flint, and

in some places of it also resem∣bling the Grain of a Flint: It would very readily Cut Glass, and would not without difficulty (e∣specially in some parts of it) be scratch'd by a Black hard Flint: It would also as readily strike Fire against a Steel, as also against a Flint.

Thirdly, in the Closeness of it; for, though all the Microscopical Pores of the Wood were very Con∣spicuous in one position, yet by altering that position of the Po∣lish'd Surface to the Light, it was also manifest that those Pores ap∣pear'd darker than the rest of the Body, only because they were fill'd up with a more Dusky Sub∣stance, and not because they were hollow.

Fourthly, in its Incumbustible∣ness, 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; yet it

seem'd not at all to have dimi∣nish'd its extention; but only I found it to have chang'd its Co∣lou••, and to have put on a more Dark and Dusky Brown Hue. 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 farther observable also, that as it did not Consume like Wood; so neither did it Crack and Fly 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 Vi∣negar upon the Stone, I found it presently to yield very many Bubbles, just like those which may be observ'd in Spirit of Vi∣negar when it Corrodes Coral; tho' I guess many of those Bubbles proceeded from the small parcels of Air, which were driven out of the Pores of this PETRIFIED sub∣stance,

by the insinuating Liquid Menstruum.

Sixthly, in its Rididness, and F••iability; being not at all Flexi∣ble, but Brittle like a Flint; in∣somuch that with one knock of a Hammer I broke off a small piece of it, and with the same Hammer quickly beat it to pretty fine Pow∣der upon an Anvil.

Seventhly, it seem'd also very differing from Wood to the Touch, feeling more Cold than Wood usu∣ally does, and much like other close Stones and Minerals.

The Reasons of all which Phoeno∣mena seem to be:

That this PETRIFIED Wood having lain in some place where it was well soak'd with PETRI∣FYING Water (that is, such a Water as is well impregnated with Stony and Earthy Particles) did by degrees separate, either by Strain∣ing and Filtration, or perhaps by

Praecipitation, Cohoesion or Coagu∣lation, abundance of Stony Parti∣cles from that permeating Water: Which Stony Particles having, by means of the fluid Vehicle, con∣vey'd themselves not only into the Microscopical Pores, and so perfectly stop'd them up; but al∣so into the Pores, which may per∣haps be even in that part of the Wood, which, through the Micro∣scope, appears most solid; do there∣by so augment the Weight of the Wood, as to make it above three times heavier than Water, and perhaps six times as heavy as it was when Wood: Next, they hereby so lock up and fetter the parts of the Wood, that the Fire cannot easily make them fly a∣way, but the Action of the Fire upon them is only able to Char those parts as it were, like as a piece of Wood, if it be clos'd very fast up in Clay, and kept a good while Red-hot in the Fire, will by the heat of the Fire be Charr'd, and

not Consum'd; which may per∣haps be the Reason why the PE∣TRIFIED Substance appear'd of a blackish Brown Colour after it had been burnt.

By this intrusion of the Petri∣fied Particles, it also becomes hard and friable; for the smaller Pores of the Wood being perfectly stuf∣fed up with these Stony Particles; the Particles of the Wood have few or no Pores in which they can reside, and consequently, no Flexion or yielding can be caus'd in such a Substance.

The remaining Particles like∣wise of the Wood; among the Stony Particles, may keep them from cracking and flying, as they are very apt to do in a Flint. HOOK's Microg. Observ. XVII.

Among the several Kinds of the PETRESCENT Liquors, I have ob∣served a sort that is of so fine a Substance, and yet of so PETRI∣FYING a Vertue, that it will Penetrate and PETRIFY Bodies of

very different Kinds, and yet scarce, if at all, visibly increase their bulk, or change their Shape or Colour. To which purpose, I Remember, that I have seen divers Animal and Vegetable Substances so PETRIFI∣ED, as scarce at all to be taken no∣tice of, by their appearance, to have been alter'd by the Operation of the PETRESCENT Liquor. I have with Pleasure seen a thin Cream-Cheese turn'd into Stone, where the Size, Shape, and Colour even of the Wrinckles, and the blueish Mold (which it seems it began to have when the Liquor Invaded it) were so well preserv'd, that an Hungry Man would not have scru∣pl'd to have fallen upon it as a good Bit. And as for the Hardness, that this PETRESCENT Juice can give to the Body that it Penetrates, I shall only tell you, that I have had (and I think yet have) a pretty quantity of Wood, PETRIFIED in England, which retaining its former Figure, and Grain, and scarce at

all visibly increas'd in Bulk, was so very hard, that I could make Im∣pressions with it upon Iron, and Glass it self, and make it strike Fire like an Excellent Flint. To which I shall here add, that the Stone parts did not suffer the Wood, which they had Penetrated, to be reduc'd in the Fire, either to Ashes or Charcole. And I have by me a Lump of Mine∣ral Substances, wherein a PETRE∣SCENT Liquor, that fills the large Intervals between them, is Tran∣sparent enough, and harder than most Stones, as far as we could guess by some tryal of it made by a skil∣ful Ingraver of Gems. And to these Instances might be added many o∣thers, if it did not by these few sufficiently appear, that PETRI∣FICK Agents may insinuate them∣selves into the Pores of Various Bodies, and turn them into Stone, without otherwise destroying their Pristine Nature, or so much as their Former Figure. BOYLE of Gems, Pag. 124, 125.

Where there are PETRESCENT Liquors mingled with common Water, there may, by divers acci∣dents, and particularly an hot Summer, a sufficient Discharge be made of the superflous Moisture, to make the more disposed parts of the PETRESCENT Liquor to Co∣agulate; and afterwards the Coa∣gulation may be suspended, either by the supervening of a Colder Season, as Winter; or even in Sum∣mer it self, by a plentiful Rain, or the effect of it, a Land-Flood, which might check the progress of Coalitions by over much diluting the Liquor, that might else have turn'd into Stone. BOILE ibidem, pag. 143.

For ought we know, in those ve∣ry Places, where now there is no∣thing to be seen but loose Stones, and perhaps Beds of Stone themselves, in those very Places (I say) there may in times past have been PE∣TRESCENT Liquors, whether Stag∣nant or Running.

For, I have in another place shew'd, that Earthquakes, Inundations of Seas and Rivers, Sinkings of Ground, Incroachments of the Land on the Water, Fiery Erupti∣ons, and other such Accidents, (some related by Authentick Au∣thors, and others happening in our own times, in places, some of which I had the curiosity to see,) have a∣mong other odd Effects, been able to dry or choak up Pools and Lakes, and to stop and quite divert the course not only of Springs, but of Rivers, so as to leave no Footsteps of them, where they plentifully flow'd before. IDEM Ibid. pag. 157.