Micrographia Part 11

And therefore, what ever is by some, who have written of it, and particularly by _Francisco Stelluto_, wrote a Treatise in _Italian_ of that Subject, which was Printed at _Rome_, 1637, affirm'd that it is a certain kind of Clay or Earth, which in tract of time is turn'd into Wood; I rather suspect the quite contrary, that it was at first certain great Trees of Fir or Pine, which by some Earthquake, or other casualty, came to be buried under the Earth, and was there, after a long time's residence (according to the several natures of the encompa.s.sing adjacent parts) either rotted and turn'd into a kind of Clay, or _petrify'd_ and turn'd into a kind of Stone, or else had its pores fill'd with certain Mineral juices, which being stay'd in them, and in tract of time coagulated, appear'd, upon cleaving out, like small Metaline Wires, or else from some flames or scorching forms that are the occasion oftentimes, and usually accompany Earthquakes, might be blasted and turn'd into Coal, or else from certain _subterraneous_ fires which are affirm'd by that Authour to abound much about those parts (namely, in a Province of _Italy_, call'd _Umbria_, now the _Dutchie_ of _Spoletto_, in the Territory of _Todi_, anciently call'd _Tudor_; and between the two Villages of _Collesecco_ and _Rosaro_ not far distant from the high-way leading to _Rome_, where it is found in greater quant.i.ty then elsewhere) are by reason of their being encompa.s.sed with Earth, and so kept close from the dissolving Air, charr'd and converted into Coal. It would be too long a work to describe the several kinds of pores which I met withall, and by this means discovered in several other Vegetable bodies; nor is it my present design to expatiate upon Instances of the same kind, but rather to give a Specimen of as many kinds as I have had opportunity as yet of observing, reserving the prosecution and enlarging on particulars till a more fit opportunity; and in prosecution of this design, I shall here add:

Observ. XVII. _Of _Petrify'd wood_, and other _Petrify'd bodies_._

Of this sort of substance, I observ'd several pieces of very differing kinds, both for their outward shape, colour, grain, _texture_, hardness, &c. some being brown and redish; others gray, like a Hone; others black, and Flint-like: some soft, like a Slate or Whetstone, others as hard as a Flint, and as brittle. That which I more particular examin'd, was a piece about the bigness of a mans hand, which seem'd to have been a part of some large tree, that by rottenness had been broken off from it before it began to be _petrify'd_.

And indeed, all that I have yet seen, seem to have been rotten Wood before the petrifaction was begun; and not long since, examining and viewing a huge great _Oak_, that seem'd with meer age to be rotten as it stood, I was very much confirm'd in this opinion; for I found, that the grain, colour, and shape of the Wood, was exactly like this _petrify'd_ substance; and with a _Microscope_, I found, that all those _Microscopical_ pores, which in sappy or firm and sound Wood are fill'd with the natural or innate juices of those Vegetables, in this they were all empty, like those of _Vegetables charr'd_; but with this difference, that they seem'd much larger then I have seen any in _Char-coals_; nay, even then those of Coals made of great blocks of Timber, which are commonly call'd _Old-coals_.

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 _interst.i.tia_ between them, then in the rotten Wood, where that natural juice seems onely to be wash'd away by _advent.i.tious_ or unnatural moisture; and so though the natural juice be wasted from between the firm parts, yet those parts are kept asunder by the _advent.i.tious_ 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.

The other Observations on this _petrify'd_ substance, that a while since, by the appointment of the _Royal Society_, I made, and presented to them an account of, were these that follow, which had the honour done them 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 Gla.s.s) _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 3 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 Gla.s.s, 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_, though perhaps many of those small Bubbles might proceed from some small parcels of Air which were driven out of the pores of this _petrify'd_ substance by the insinuating liquid _menstruum_.

Sixthly, in its _rigidness_, and _friability_, being not at all flexible but brittle like a Flint, insomuch that I could with one knock of a Hammer break off a piece of it, and with a few more, reduce that into a pretty fine powder.

Seventhly, it seem'd also very differing from Wood to the _touch_, _feeling_ more cold then Wood usually does, and much like other close stones and Minerals.

The Reasons of all which _Phaenomena_ seem to be,

That _petrify'd_ Wood having lain in some place where it was well soak'd with _petrifying_ water (that is, such a water as is well _impregnated_ with stony and earthy particles) did by degrees separate, either by straining and _filtration_, or perhaps, by _precipitation_, _cohesion_ or _coagulation_, abundance of stony particles from the permeating water, which stony particles, being by means of the fluid _vehicle_ convey'd, not onely into the _Microscopical_ pores, and so perfectly stoping them up, but also into the pores or _interst.i.tia_, which may, perhaps, be even in the texture or _Schematisme_ of that part of the Wood, which, through the _Microscope_, appears most solid, do thereby so augment the weight of the Wood, as to make it above three times heavier then water, and perhaps, six times as heavie as it was when Wood.

Next, they thereby so lock up and fetter the parts of the Wood, that the fire cannot easily make them flie away, but the action of the fire upon them is onely able to _Char_ those parts, as it were, like 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, perhaps, also be somewhat of the cause, why the _petrify'd_ substance appear'd of a dark brown colour after it had been burnt.

By this _intrusion_ of the _petrifying_ particles, this substance also becomes hard and _friable_; for the smaller pores of the Wood being perfectly wedg'd, and stuft up with those stony particles, the small parts of the Wood have no places or pores into which they may slide upon bending, and consequently little or no flexion or yielding at all can be caus'd in such a substance.

The remaining particles likewise of the Wood among the stony particles, may keep them from cracking and flying when put into the fire, as they are very apt to do in a Flint.

Nor is Wood the onely substance that may by this kind of _trans.m.u.tation_ be chang'd into stone; for I my self have seen and examin'd very many kinds of substances, and among very credible Authours, we may meet with Histories of such _Metamorphoses_ wrought almost on all kind of substances, both _Vegetable_ and _Animal_, which Histories, it is not my business at present, either to relate, or _epitomise_, but only to set down some Observation I lately made on several kind of _petrify'd_ Shels, found about _Keinsham_, which lies within four or five miles of _Bristol_, which are commonly call'd _Serpentine-stones._

Examining several of these very curiously figur'd bodies (which are commonly thought to be Stones form'd by some extraordinary _Plastick virtue_ _latent_ in the Earth itself) I took notice of these particulars:

First, that these figured bodies, or stones, were of very differing substances, as to hardness: some of Clay, some Marle, some soft Stone, almost of the hardness of those soft stones which Masons call Fire-stone, others as hard as Portland stone, others as hard as Marble, and some as hard as a Flint or Crystal.

Next, they were of very differing substances as to transparency and colour; some white, some almost black, some brown, some Metalline, or like Marchasites; some transparent like white Marble, others like flaw'd Crystal, some gray, some of divers colours; some radiated like those long _petrify'd drops_, which are commonly found at the _Peak_, and in other _subterraneous caverns_, which have a kind of pith in the middle.

Thirdly, that they were very different as to the manner of their outward figuration; for some of them seem'd to have been the substance that had fill'd the Sh.e.l.l of some kind of Shel-fish; others, to have been the substance that had contain'd or enwrapp'd one of those Shels, on both which, the perfect impression either of the inside or outside of such Sh.e.l.ls seem'd to be left, but for the most part, those impressions seem'd to be made by an imperfect or broken Sh.e.l.l, the great end or mouth of the Sh.e.l.l being always wanting, and often times the little end, and sometimes half, and in some there were impressions, just as if there had been holes broken in the figurating, imprinting or moulding Sh.e.l.l; some of them seem'd to be made by such a Sh.e.l.l very much brused or flaw'd, insomuch that one would verily have thought that very figur'd stone had been broken or brused whilst a gelly, as 'twere, and so hardned, but within in the grain of the stone, there appear'd not the least sign of any such bruse or breaking, but onely on the very uttermost superficies.

Fourthly, they were very different, as to their outward covering, some having the perfect Sh.e.l.l, both in figure, colour, and substance, sticking on upon its surface, and adhering to it, but might very easily be separated from it, and like other common _c.o.c.kle_ or _Scolop-shels_, which some of them most accurately resembled, were very dissoluble in common _Vinegar_, others of them, especially those _Serpentine_, or _Helical stones_ were cover'd or retained the s.h.i.+ning or Pearl-colour'd substance of the inside of a Shel, which substance, on some parts of them, was exceeding thin, and might very easily be rubbed off; on other parts it was pretty thick, and retained a white coat, or flaky substance on the top, just like the outsides of such Sh.e.l.ls; some of them had very large pieces of the Sh.e.l.l very plainly sticking on to them, which were easily to be broken or flaked off by degrees: they likewise, some of them retain'd all along the surface of them very pretty kind of _sutures_, such as are observ'd in the skulls of several kinds of living creatures, which _sutures_ were most curiously shap'd in the manner of leaves, and every one of them in the same Sh.e.l.l, exactly one like another, which I was able to discover plainly enough with my naked eye, but more perfectly and distinctly with my _Microscope_; all these sutures, by breaking some of these stones, I found to be the _termini_, or boundings of certain _diaphragms_, or part.i.tions, which seem'd to divide the cavity of the Sh.e.l.l into a mult.i.tude of very proportionate and regular _cells_ or _caverns_, these _Diaphragms_, in many of them, I found very perfect and compleat, of a very distinct substance from that which fill'd the cavities, and exactly of the same kind with that which covered the outside, being for the most part whitish, or _mother-of-pearl_ colour'd.

As for the cavities between those _Diaphragms_, I found some of them fill'd with Marle, and others with several kinds of stones, others, for the most part hollow, onely the whole cavity was usually covered over with a kind of _tartareous petrify'd_ substance, which stuck about the sides, and was there shot into very curious regular Figures, just as _Tartar_, or other dissolv'd Salts are observ'd to stick and _crystallize_ about the sides of the containing Vessels; or like those little _Diamants_ which I before observed to have covered the vaulted cavity of a Flint; others had these cavities all lin'd with a kind of _metalline_ or _marchasite-like_ substance, which with a _Microscope_ I could as plainly see most curiously and regularly figured, as I had done those in a Flint.

From all which, and several other particulars which I observ'd, I cannot but think, that all these, and most other kinds of stony bodies which are found thus strangely figured, do owe their formation and figuration, not to any kind of _Plastick virtue_ inherent in the earth, but to the Sh.e.l.ls of certain Shel-fishes, which, either by some Deluge, Inundation, Earthquake, or some such other means, came to be thrown to that place, and there to be fill'd with some kind of Mudd or Clay, or _petrifying_ Water, or some other substance, which in tract of time has been settled together and hardned in those sh.e.l.ly moulds into those shaped substances we now find them; that the great and thin end of these Sh.e.l.ls by that Earthquake, or what ever other extraordinary cause it was that brought them thither, was broken off; and that many others were otherwise broken, bruised and disfigured; that these Sh.e.l.ls which are thus _spirallied_ and separated with _Diaphragmes_, were some kind of _Nautili_ or _Porcelane sh.e.l.ls_; and that others were sh.e.l.ls of _c.o.c.kles_, _Muscles_, _Periwincles_, _Scolops_, &c. of various sorts; that these Sh.e.l.ls in many, from the particular nature of the containing or enclos'd Earth, or some other cause, have in tract of time rotted and mouldred away, and onely left their impressions, both on the containing and contained substances; and so left them pretty loose one within another, so that they may be easily separated by a knock or two of a Hammer. That others of these Sh.e.l.ls, according to the nature of the substances adjacent to them, have, by a long continuance in that posture, been _petrify'd_ and turn'd into the nature of stone, just as I even now observ'd several sorts of Wood to be. That oftentimes the Sh.e.l.l may be found with one kind of substance within, and quite another without; having, perhaps, been fill'd in one place, and afterwards translated to another, which I have very frequently observ'd in _c.o.c.kle_, _Muscle_, _Periwincle_, and other sh.e.l.ls, which I have found by the Sea side. Nay, further, that some parts of the same Sh.e.l.l may be fill'd in one place, and some other caverns in another, and others in a third, or a fourth, or a fifth place, for so many differing substances have I found in one of these _petrify'd_ Sh.e.l.ls, and perhaps all these differing from the encompa.s.sing earth or stone; the means how all which varieties may be caus'd, I think, will not be difficult to conceive, to any one that has taken notice of those Sh.e.l.ls, which are commonly found on the Sea sh.o.r.e: And he that shall throughly examine several kinds of such curiously form'd stones, will (I am very apt to think) find reason to suppose their generation or formation to be ascribable to some such accidents as I have mention'd, and not to any _Plastick virtue_: For it seems to me quite contrary to the infinite prudence of Nature, which is observable in all its works and productions, to design every thing to a determinate end, and for the attaining of that end, makes use of such ways as are (as farr as the knowledge of man has yet been able to reach) altogether consonant, and most agreeable to man's reason, and of no way or means that does contradict, or is contrary to humane Ratiocination; whence it has a long time been a general observation and _maxime_, that _Nature does nothing in vain_; It seems, I say, contrary to that great Wisdom of Nature, that these prettily shap'd bodies should have all those curious Figures and contrivances (which many of them are adorn'd and contriv'd with) generated or wrought by a _Plastick virtue_, for no higher end, then onely to exhibite such a form; which he that shall throughly consider all the circ.u.mstances of such kind of Figur'd bodies, will, I think, have great reason to believe, though, I confess, one cannot presently be able to find out what Nature's designs are. It were therefore very desirable, that a good collection of such kind of figur'd stones were collected; and as many particulars, circ.u.mstances, and informations collected with them as could be obtained, that from such a History of Observations well rang'd, examin'd and digested, the true original or production of all those kinds of stones might be perfectly and surely known; such as are _Thunder-stones_, _Lapides Stellares_, _Lapides Judaici_, and mult.i.tudes of other, whereof mention is made in _Aldonandus_, _Wormius_, and other Writers of Minerals.

Observ. XVIII. _Of the _Schematisme_ or _Texture_ of _Cork_, and of the Cells and Pores of some other such frothy Bodies._

I took a good clear piece of Cork, and with a Pen-knife sharpen'd as keen as a Razor, I cut a piece of it off, and thereby left the surface of it exceeding smooth, then examining it very diligently with a _Microscope_, me thought I could perceive it to appear a little porous; but I could not so plainly distinguish them, as to be sure that they were pores, much less what Figure they were of: But judging from the lightness and yielding quality of the Cork, that certainly the texture could not be so curious, but that possibly, if I could use some further diligence, I might find it to be discernable with a _Microscope_, I with the same sharp Penknife, cut off from the former smooth surface an exceeding thin piece of it, and placing it on a black object Plate, because it was it self a white body, and casting the light on it with a deep _plano-convex Gla.s.s_, I could exceeding plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular; yet it was not unlike a Honey-comb in these particulars.

First, in that it had a very little solid substance, in comparison of the empty cavity that was contain'd between, as does more manifestly appear by the Figure A and B of the XI. _Scheme_, for the _Interst.i.tia_, or walls (as I may so call them) or part.i.tions of those pores were neer as thin in proportion to their pores, as those thin films of Wax in a Honey-comb (which enclose and const.i.tute the _s.e.xangular celts_) are to theirs.

Next, in that these pores, or cells, were not very deep, but consisted of a great many little Boxes, separated out of one continued long pore, by certain _Diaphragms_, as is visible by the Figure B, which represents a sight of those pores split the long-ways.

I no sooner discern'd these (which were indeed the first _microscopical_ pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this) but me thought I had with the discovery of them, presently hinted to me the true and intelligible reason of all the _Phaenomena_ of Cork; As,

First, if I enquir'd why it was so exceeding light a body? my _Microscope_ could presently inform me that here was the same reason evident that there is found for the lightness of froth, an empty Honey-comb, Wool, a Spunge, a Pumice-stone, or the like; namely, a very small quant.i.ty of a solid body, extended into exceeding large dimensions.

Next, it seem'd nothing more difficult to give an intelligible reason, why Cork is a body so very unapt to suck and drink in Water, and consequently preserves it self, floating on the top of Water, though left on it never so long: and why it is able to stop and hold air in a Bottle, though it be there very much condens'd and consequently presses very strongly to get a pa.s.sage out, without suffering the least bubble to pa.s.s through its substance. For, as to the first, since our _Microscope_ informs us that the substance of Cork is altogether fill'd with Air, and that that Air is perfectly enclosed in little Boxes or Cells distinct from one another. It seems very plain, why neither the Water, nor any other Air can easily insinuate it self into them, since there is already within them an _intus existens_, and consequently, why the pieces of Cork become so good floats for Nets, and stopples for Viols, or other close Vessels.

And thirdly, if we enquire why Cork has such a springiness and swelling nature when compress'd? and how it comes to suffer so great a compression, or seeming penetration of dimensions, so as to be made a substance as heavie again and more, bulk for bulk, as it was before compression, and yet suffer'd to return, is found to extend it self again into the same s.p.a.ce?

Our _Microscope_ will easily inform us, that the whole ma.s.s consists of an infinite company of small Boxes or Bladders of Air, which is a substance of a springy nature, and that will suffer a considerable condensation (as I have several times found by divers trials, by which I have most evidently condens'd it into less then a twentieth part of its usual dimensions neer the Earth, and that with no other strength then that of my hands without any kind of forcing Engine, such as Racks, Leavers, Wheels, Pullies, or the like, but this onely by and by) and besides, it seems very probable that those very films or sides of the pores, have in them a springing quality, as almost all other kind of Vegetable substances have, so as to help to restore themselves to their former position.

And could we so easily and certainly discover the _Schematisme_ and _Texture_ even of these films, and of several other bodies, as we can these of Cork; there seems no probable reason to the contrary, but that we might as readily render the true reason of all their _Phaenomena_; as namely, what were the cause of the springingess, and toughness of some, both as to their flexibility and rest.i.tution. What, of the friability or brittleness of some others, and the like; but till such time as our _Microscope_, or some other means, enable us to discover the true _Schematism_ and _Texture_ of all kinds of bodies, we must grope, as it were, in the dark, and onely ghess at the true reasons of things by similitudes and comparisons.

But, to return to our Observation. I told several lines of these pores, and found that there were usually about threescore of these small Cells placed end-ways in the eighteenth part of an Inch in length, whence I concluded there must be neer eleven hundred of them, or somewhat more then a thousand in the length of an Inch, and therefore in a square Inch above a Million, or 1166400. and in a Cubick Inch, above twelve hundred Millions, or 1259712000. a thing almost incredible, did not our _Microscope_ a.s.sure us of it by ocular demonstration; nay, did it not discover to us the pores of a body, which were they _diaphragm'd_, like those of Cork, would afford us in one Cubick Inch, more then ten times as many little Cells, as is evident in several charr'd Vegetables; so prodigiously curious are the works of Nature, that even these conspicuous pores of bodies, which seem to be the channels or pipes through which the _Succus nutritius_, or natural juices of Vegetables are convey'd, and seem to correspond to the veins, arteries and other Vessels in sensible creatures, that these pores I say, which seem to be the Vessels of nutrition to the vastest body in the World, are yet so exceeding small, that the _Atoms_ which _Epicurus_ fancy'd would go neer to prove too bigg to enter them, much more to const.i.tute a fluid body in them.

And how infinitely smaller then must be the Vessels of a Mite, or the pores of one of those little Vegetables I have discovered to grow on the back-side of a Rose-leaf, and shall anon more fully describe, whose bulk is many millions of times less then the bulk of the small shrub it grows on; and even that shrub, many millions of times less in bulk then several trees (that have heretofore grown in _England_, and are this day flouris.h.i.+ng in other hotter Climates, as we are very credibly inform'd) if at least the pores of this small Vegetable should keep any such proportion to the body of it, as we have found these pores of other Vegetables to do to their bulk. But of these pores I have said more elsewhere.

To proceed then, Cork seems to be by the transverse const.i.tution of the pores, a kind of _Fungus_ or Mushrome, for the pores lie like so many Rays tending from the center, or pith of the tree, outwards; so that if you cut off a piece from a board of Cork transversly, to the flat of it, you will, as it were, split the pores, and they will appear just as they are express'd in the Figure B of the XI. _Scheme_. But if you shave off a very thin piece from this board, parallel to the plain of it, you will cut all the pores transversly, and they will appear almost as they are express'd in the Figure A, save onely the solid _Interst.i.tia_ will not appear so thick as they are there represented.

So that Cork seems to suck its nourishment from the subjacent bark of the Tree immediately, and to be a kind of excrescence, or a substance distinct from the substances of the entire Tree, something _a.n.a.logus_ to the Mushrome, or Moss on other Trees, or to the hairs on Animals. And having enquir'd into the History of Cork, I find it reckoned as an excrescency of the bark of a certain Tree, which is distinct from the two barks that lie within it, which are common also to other trees; That 'tis some time before the Cork that covers the young and tender sprouts comes to be discernable; That it cracks, flaws, and cleaves into many great chaps, the bark underneath remaining entire; That it may be separated and remov'd from the Tree, and yet the two under-barks (such as are also common to that with other Trees) not at all injur'd, but rather helped and freed from an external injury. Thus _Jonstonus_ in _Dendrologia_, speaking _de Subere_, says, _Arbor est procera, Lignum est robustum, dempto cortice in aquis non fluitat, Cortice in orbem detracto juvatur, crascescens enim praestringit & strangulat, intra triennium iterum repletur: Caudex ubi adolescit cra.s.sus, cortex superior densus carnosus, duos digitos cra.s.sus, scaber, rimosus, & qui nisi detrahatur dehiscit, alioque subnascente expellitur, interior qui subest novellus ita rubet ut arbor minio picta videatur_. Which Histories, if well consider'd, and the tree, substance, and manner of growing, if well examin'd, would, I am very apt to believe, much confirm this my conjecture about the origination of Cork.

Nor is this kind of Texture peculiar to Cork onely; for upon examination with my _Microscope_, I have found that the pith of an Elder, or almost any other Tree, the inner pulp or pith of the Cany hollow stalks of several other Vegetables: as of Fennel, Carrets, Daucus, Bur-docks, Teasels, Fearn, some kinds of Reeds, &c. have much such a kind of _Schematisme_, as I have lately shewn that of Cork, save onely that here the pores are rang'd the long-ways, or the same ways with the length of the Cane, whereas in Cork they are transverse.

The pith also that fills that part of the stalk of a Feather that is above the Quil, has much such a kind of texture, save onely that which way soever I set this light substance, the pores seem'd to be cut transversly; so that I ghess this pith which fills the Feather, not to consist of abundance of long pores separated with Diaphragms, as Cork does, but to be a kind of solid or hardned froth, or a _congeries_ of very small bubbles consolidated in that form, into a pretty stiff as well as tough concrete, and that each Cavern, Bubble, or Cell, is distinctly separate from any of the rest, without any kind of hole in the encompa.s.sing films, so that I could no more blow through a piece of this kinde of substance, then I could through a piece of Cork, or the sound pith of an Elder.

But though I could not with my _Microscope_, nor with my breath, nor any other way I have yet try'd, discover a pa.s.sage out of one of those cavities into another, yet I cannot thence conclude, that therefore there are none such, by which the _Succus nutritius_, or appropriate juices of Vegetables, may pa.s.s through them; for, in several of those Vegetables, whil'st green, I have with my _Microscope_, plainly enough discover'd these Cells or Poles fill'd with juices, and by degrees sweating them out; as I have also observed in green Wood all those long _Microscopical_ pores which appear in Charcoal perfectly empty of any thing but Air.