That which we may call the white was pretty whitish neer the yelk, but more duskie towards the shell; some of them I could plainly perceive to be shot or radiated like a Pyrites or fire-stone; the yelk in some I saw hollow, in others fill'd with a duskie brown and porous substance like a kind of pith.

The small pores, or interstitia eeee betwixt the Globules, I plainly saw, and found by other trials to be every way pervious to air and water, for I could blow through a piece of this stone of a considerable thickness, as easily as I have blown through a Cane, which minded me of the pores which Des Cartes allow his materia subtilis between the aethereal globules.

The object, through the Microscope, appears like a Congeries or heap of Pibbles, such as I have often seen cast up on the shore, by the working of the Sea after a great storm, or like (in shape, though not colour) a company of small Globules of Quicksilver, look'd on with a Microscope, when reduc'd into that form by the way lately mentioned. And perhaps, this last may give some hint at the manner of the formation of the former: For supposing some Lapidescent substance to be generated, or some way brought (either by some commixture of bodies in the Sea it self, or protruded in, perhaps, out of some subterraneous caverns) to the bottom of the Sea, and there remaining in the form of a liquor like Quicksilver, heterogeneous to the ambient Saline fluid, it may by the working and tumblings of the Sea to and fro be jumbled and comminuted into such Globules as may afterwards be hardned into Flints, the lying of which one upon another, when in the Sea, being not very hard, by reason of the weight of the incompassing fluid, may cause the undermost to be a little, though not much, varied from a globular Figure. But this only by the by.

After what manner this Kettering-stone should be generated I cannot learn, having never been there to view the place, and observe the circumstances; but it seems to me from the structure of it to be generated from some substance once more fluid, and afterwards by degrees growing harder, almost after the same manner as I supposed the generation of Flints to be made.

But whatever were the cause of its curious texture, we may learn this information from it; that even in those things which we account vile, rude, and coorse, Nature has not been wanting to shew abundance of curiosity and excellent Mechanisme.

We may here find a Stone by help of a Microscope, to be made up of abundance of small Balls, which do but just touch each other, and yet there being so many contacts, they make a firm hard mass, or a Stone much harder then Free-stone.

Next, though we can by a Microscope discern so curious a shape in the particles, yet to the naked eye there scarce appears any such thing; which may afford us a good argument to think, that even in those bodies also, whose texture we are not able to discern, though help'd with Microscopes, there may be yet latent so curious a Schematisme, that it may abundantly satisfie the curious searcher, who shall be so happy as to find some way to discover it.

Next, we here find a Stone, though to the naked eye a very close one, yet every way perforated with innumerable pores, which are nothing else but the interstitia, between those multitudes of minute globular particles, that compose the bulk it self, and these pores are not only discover'd by the Microscope, but by this contrivance.

I took a pretty large piece of this stone, and covering it all over with cement, save only at two opposite parts, I found my self able, by blowing in at one end that was left open, to blow my spittle, with which I had wet the other end, into abundance of bubbles, which argued these pores to be open and pervious through the whole stone, which affords us a very pretty instance of the porousness of some seemingly close bodies, of which kind I shall anon have occasion to subjoyn many more, tending to prove the same thing.

I must not here omit to take notice, that in this body there is not a vegetative faculty that should so contrive this structure for any peculiar use of vegetation or growth, whereas in the other instances of vegetable porous bodies, there is an anima or forma informans, that does contrive all the Structures and Mechanismes of the constituting body, to make them subservient and usefull to the great Work or Function they are to perform. And so I ghess the pores in Wood, and other vegetables, in bones, and other Animal substances, to be as so many channels, provided by the Great and Alwise Creator, for the conveyance of appropriated juyces to particular parts. And therefore, that this may tend, or be pervious all towards one part, and may have impediments, as valves or the like, to any other; but in this body we have very little reason so suspect there should be any such design, for it is equally pervious every way, not onely forward, but backwards, and side-ways, and seems indeed much rather to be Homogeneous or similar to those pores, which we may with great probability believe to be the channels of pellucid bodies, not directed, or more open any one way, then any other, being equally pervious every way. And, according as these pores are more or greater in respect of the interstitial bodies, the more transparent are the so constituted concretes; and the smaller those pores are, the weaker is the Impulse of light communicated through them, though the more quick be the progress.

Upon this Occasion, I hope it will not be altogether unseasonable, if I propound my conjectures and Hypothesis about the medium and conveyance of light.

I suppose then, that the greatest part of the Interstitia of the world, that lies between the bodies of the Sun and Starrs, and the Planets, and the Earth, to be an exceeding fluid body, very apt and ready to be mov'd, and to communicate the motion of any one part to any other part, though never so far distant: Nor do I much concern my self, to determine what the Figure of the particles of this exceedingly subtile fluid medium must be, nor whether it have any interstitiated pores or vacuities, it being sufficient to solve all the Phaenomena to suppose it an exceedingly fluid, or the most fluid body in the world, and as yet impossible to determine the other difficulties.

That being so exceeding fluid a body, it easily gives passage to all other bodies to move to and fro in it.

That it neither receives from any of its parts, or from other bodies; nor communicates to any of its parts, or to any other body, any impulse, or motion in a direct line, that is not of a determinate quickness. And that when the motion is of such determinate swiftness, it both receives, and communicates, or propagates an impulse or motion to any imaginable distance in streight lines, with an unimaginable celerity and vigour.

That all kind of solid bodies consist of pretty massie particles in respect of the particles of this fluid medium, which in many places do so touch each other, that none of this fluid medium interposes much after the same mannner (to use a gross similitude) as a heap of great stones compose one great congeries or mass in the midst of the water.

That all fluid bodies which we may call tangible, are nothing but some more subtile parts of those particles, that serve to constitute all tangible bodies.

That the water, and such other fluid bodies, are nothing but a congeries of particles agitated or made fluid by it in the same manner as the particles of Salt are agitated or made fluid by a parcel of water, in which they are dissolv'd, and subsiding to the bottom of it, constitute a fluid body, much more massie and dense, and less fluid then the pure water it self.

That the air on the other side is a certain company of particles of quite another kind, that is, such as are very much smaller, and more easiely moveable by the motion of this fluid medium; much like those very subtile parts of Cochenel, other very deep tinging bodies, where by a very small parcel of matter is able to tinge and diffuse it self over a very great quantity of the fluid dissolvent; or somewhat after that manner, as smoak, and such like minute bodies, or steams, are observ'd to tinge a very great quantity of air; onely this last similitude is deficient in one propriety, and that is a perpetuity or continuance in that state of commixture with the air, but the former does more neerly approach to the nature and manner of the air's being dissolv'd by this fluid or AEther. And this Similitude will further hold in these proprieties; that as those tinctures may be increased by certain bodies, so may they be precipitated by others, as I shall afterwards shew it to be very probable, that the like accidents happen even to the Air it self.

Further, as these solutions and tinctures do alter the nature of these fluid bodies, as to their aptness to propagate a motion or impulse through them, even so does the particles of the Air, Water, and other fluid bodies, and of Glass, Crystal, &c. which are commixt with this bulk of the AEther alter the motion of the propagated pulse of light; that is, where these more bulkie particles are more plentifull, and consequently a lesser quantity of the AEther between them to be mov'd, there the motion must necessarily be the swifter, though not so robust, which will produce those effects, which I have (I hope) with some probability, ascribed to it in the digression about Colours, at the end of the Observations on Muscovy-glass.

Now, that other Stones, and those which have the closest and hardest textures, and seem (as far as we are able to discover with our eyes, though help'd with the best Microscopes) freest from pores, are yet notwithstanding replenish'd with them, an Instance or two will, I suppose, make more probable.

A very solid and unflaw'd piece of cleer white Marble, if it be well polish'd and glaz'd, has so curiously smooth a surface, that the best and most polish'd surface of any wrought-glass, seems not to the naked eye, nor through a Microscope, to be more smooth, and less porous. And yet, that this hard close body is replenish'd with abundance of pores, I think these following Experiments will sufficiently prove.

The first is, That if you take such a piece, and for a pretty while boyl it in Turpentine and Oyl of Turpentine, you shall find that the stone will be all imbu'd with it; and whereas before it look'd more white, but more opacous, now it will look more greasie, but be much more transparent, and if you let it lie but a little while, and then break off a part of it, you shall find the unctuous body to have penetrated it to such a determinate depth every way within the surface. This may be yet easier try'd with a piece of the same Marble, a little warm'd in the fire, and then a little Pitch or Tarr melted on the top of it; for these black bodies, by their insinuating themselves into the invisible pores of the stone, ting it with so black a hue, that there can be no further doubt of the truth of this assertion, that it abounds with small imperceptible pores.

Now, that other bodies will also sink into the pores of Marble, besides unctuous, I have try'd, and found, that a very Blue tincture made in spirit of Urine would very readily and easily sink into it, as would also several tinctures drawn with spirit of Wine.

Nor is Marble the only seemingly close stone, which by other kinds of Experiments may be found porous; for I have by this kind of Experiment on divers other stones found much the same effect, and in some, indeed much more notable. Other stones I have found so porous, that with the Microscope I could perceive several small winding holes, much like Worm-holes, as I have noted in some kind of Purbeck-stone, by looking on the surface of a piece newly flaw'd off, for if otherwise, the surface has been long expos'd to the Air, or has been scraped with any tool, those small caverns are fill'd with dust, and disappear.

And to confirm this Conjecture, yet further, I shall here insert an excellent account, given into the Royal Society by that Eminently Learned Physician, Doctor Goddard, of an Experiment, not less instructive then curious and accurate, made by himself on a very hard and seemingly close stone call'd Oculus Mundi, as I find it preserv'd in the Records of that Honourable Society.

A small stone of the kind, call'd by some Authours, Oculus Mundi, being dry and cloudy, weigh'd 5-209/256 Grains.

The same put under water for a night, and somewhat more, became transparent, and the superficies being wiped dry, weighed 6-3/256 Grains.

The difference between these two weights, 0-50/256 of a Grain.

The same Stone kept out of water one Day and becoming cloudy again weighed, 5-225/256 Graines.

Which was more then the first weight, 0-16/256 of a Grain.

The same being kept two Days longer weighed, 5-202/256 Graines.

Which was less then at first, 0-7/256 a Grain.

Being kept dry something longer it did not grow sensibly lighter.

Being put under water for a night and becoming again transparent and wiped dry, the weight was, 6-3/256 Grains, the same with the first after putting in water, and more then the last weight after keeping of it dry, 0-57/256 of a Grain.

Another Stone of the same kind being variegated with milky white and gray like some sorts of Agates, while it lay under water, was alwaies invironed with little Bubbles, such as appear in water a little before boyling, next the sides of the Vessel.

There were also some the like Bubbles on the Surface of the water just over it, as if either some exhalations came out of it, or that it did excite some fermentation in the parts of the water contiguous to it.

There was little sensible difference in the transparency of this Stone, before the putting under water, and after: To be sure the milky-white parts continued as before, but more difference in weight then in the former. For whereas before the putting into the water the weight was 18-97/128 Graines. After it had lyen in about four and twenty hours the weight was 20-27/128 Graines, so the difference was, 1-58/128 Graines.

The same Stone was infused in the water scalding hot, and so continued for a while after it was cold, but got no more weight then upon infusing in the cold, neither was there any sensible Difference in the weight both times.

In which Experiment, there are three Observables that seem very manifestly to prove the porousness of these seemingly close bodies: the first is their acquiring a transparency, and losing their whiteness after steeping in water, which will seem the more strongly to argue it, if what I have already said about the making transparent, or clarifying of some bodies, as the white powder of beaten Glass, and the froth of some glutinous transparent liquor be well consider'd; for thereby it will seem rational to think that this transparency arises from the insinuation of the water (which has much the same refraction with such stony particles, as may be discover'd by Sand view'd with a Microscope) into those pores which were formerly repleat with air (that has a very differing refraction, and consequently is very reflective) which seems to be confirm'd by the second Observable, namely, the increase of weight after keeping, and decrease upon drying. And thirdly, seem'd yet more sensibly confirm'd by the multitude of bubbles in the last Experiment.

We find also most Acid Salts very readily to dissolve and separate the parts of this body one from another; which is yet a further Argument to confirm the porousness of bodies, and will serve as such, to shew that even Glass also has an abundance of pores in it, since there are several liquors, that with long staying in a Glass, will so Corrode and eat into it, as at last, to make it pervious to the liquor it contain'd, of which I have seen very many Instances.

Since therefore we find by other proofs, that many of those bodies which we think the most solid ones, and appear so to our sight, have notwithstanding abundance of those grosser kind of pores, which will admit several kinds of liquors into them, why should we not believe that Glass, and all other transparent bodies abound with them, since we have many other arguments, besides the propagation of light, which seem to argue for it?

And whereas it may be objected, that the propagation of light is no argument that there are those atomical pores in glass, since there are Hypotheses plausible enough to solve those Phaenomena, by supposing the pulse onely to be communicated through the transparent body.

To this I answer, that that Hypothesis which the industrious Mersennus has publish'd about the slower motion of the end of a Ray in a denser medium, then in a more rare and thin, seems altogether unsufficient to solve abundance of Phaenomena, of which this is not the least considerable, that it is impossible from that supposition, that any colours should be generated from the refraction of the Rays; for since by that Hypothesis the undulating pulse is always carried perpendicular, or at right angles with the Ray or Line of direction, it follows, that the stroke of the pulse of light, after it has been once or twice refracted (through a Prisme, for example) must affect the eye with the same kind of stroke as if it had not been refracted at all. Nor will it be enough for a Defendant of that Hypothesis, to say, that perhaps it is because the refractions have made the Rays more weak, for if so, then two refractions in the two parallel sides of a Quadrangular Prisme would produce colours, but we have no such Phaenomena produc'd.

There are several Arguments that I could bring to evince that there are in all transparent bodies such atomical pores. And that there is such a fluid body as I am arguing for, which is the medium, or Instrument, by which the pulse of Light is convey'd from the lucid body to the enlightn'd. But that it being a digression from the Observations I was recording, about the Pores of Kettering Stone, it would be too much such, if I should protract it too long; and therefore I shall proceed to the next Observation.

* * * * *

Observ. XVI. Of Charcoal, or burnt Vegetables.

Charcoal, or a Vegetable burnt black, affords an object no less pleasant than instructive, for if you take a small round Charcoal, and break it short with your fingers, you may perceive it to break with a very smooth and sleek surface, almost like the surface of black sealing Wax; this surface, if it be look'd on with an ordinary Microscope, does manifest abundance of those pores which are also visible to the eye in many kinds of Wood, rang'd round the pith, both a in kind of circular order, and a radiant one. Of these there are a multitude in the substance of the Coal, every where almost perforating and drilling it from end to end; by means of which, be the Coal never so long, you may easily blow through it; and this you may presently find, by wetting one end of it with Spittle, and blowing at the other.

But this is not all, for besides those many great and conspicuous irregular spots or pores, if a better Microscope be made use of, there will appear an infinite company of exceedingly small, and very regular pores, so thick and so orderly set, and so close to one another, that they leave very little room or space between them to be fill'd with a solid body, for the apparent interstitia or separating sides of these pores seem so thin in some places, that the texture of a Honey-comb cannot be more porous. Though this be not every where so, the intercurrent partitions in some places being very much thicker in proportion to the holes.

Most of these small pores seem'd to be pretty round, and were rang'd in rows that radiated from the pith to the bark; they all of them seem'd to be continued open pores, running the whole length of the Stick; and that they were all perforated, I try'd by breaking off a very thin sliver of the Coal cross-ways, and then with my Microscope, diligently surveying them against the light, for by that means I was able to see quite through them.

These pores were so exceeding small and thick, that in a line of them, 1/18 part of an Inch long, I found by numbring them no less then 150. small pores; and therefore in a line of them an Inch long, must be no less then 2700. pores, and in a circular area of an Inch diameter, must be about 5725350. of the like pores; so that a Stick of an Inch Diameter, may containe no less then seven hundred and twenty five thousand, besides 5 Millions of pores, which would, I doubt not, seem even incredible, were not every one left to believe his own eyes. Nay, having since examin'd Cocus, black and green Ebony, Lignum Vitae, &c. I found, that all these Woods have their pores, abundantly smaller then those of soft light Wood; in so much, that those of Guajacum seem'd not above an eighth part of the bigness of the pores of Beech, but then the Interstitia were thicker; so prodigiously curious are the contrivances, pipes, or sluces by which the Succus nutritius, or Juyce of a Vegetable is convey'd from place to place.

This Observation seems to afford us the true reason of several Phaenomena of Coals; as

First, why they look black; and for this we need go no further then the Scheme, for certainly, a body that has so many pores in it as this is discover'd to have, from each of which no light is reflected, must necessarily look black, especially, when the pores are somewhat bigger in proportion to the intervals then they are cut in the Scheme, black being nothing else but a privation of Light, or a want of reflection; and wheresover this reflecting quality is deficient, there does that part look black, whether it be from a porousness of the body, as in this Instance, or in a deadning and dulling quality, such as I have observ'd in the Scoria of Lead, Tin, Silver, Copper, &c.

Next, we may also as plainly see the reason of its shining quality, and that is from the even breaking off of the stick, the solid interstitia 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, it will take fire, and readily burn away.

This maybe done also in any close Vessel of Glass, as a Retort, or the like, and the several fluid substances that come over may be receiv'd in a fit Recipient, which will yet further countenance this Hypothesis: And their manner of charring Wood in great quantity comes much to the same thing, namely, an application of a great heat to the body, and preserving it from the free access of the devouring air; this may be easily learn'd from the History of Charring of Coal, most excellently describ'd and publish'd by that most accomplish'd Gentleman, Mr. John Evelin, in the 100, 101, 103, pages of his Sylva, to which I shall therefore refer the curious Reader that desires a full information of it.

Next, we may learn what part of the Wood it is that is the combustible matter, for since we shall find that none, or very little of those fluid substances that are driven over into the Receiver are combustible, and that most of that which is left behind is so, it follows, that the solid interstitia of the Wood are the combustible matter. Further, the reason why uncharr'd Wood burns with a greater flame then that which is charr'd, is as evident, because those waterish or volatil parts issuing out of the fired Wood, every way, not onely shatter and open the body, the better for the fire to enter, but issuing out in vapours or wind, they become like so many little aeolipiles, or Bellows, whereby they blow and agitate the fir'd part, and conduce to the more speedy and violent consumption or dissolution of the body.

Thirdly, from the Experiment of charring of Coals (whereby we see that notwithstanding the great heat, and the duration of it, the solid parts of the Wood remain, whilest they are preserv'd from the free access of the air undissipated) we may learn, that which has not, that I know of, been publish'd or hinted, nay, not so much as thought of, by any; and that in short is this.

First, that the Air in which we live, move, and breath, and which encompasses very many, and cherishes most bodies it encompasses, that this Air is the menstruum, or universal dissolvent of all Sulphureous bodies.

Secondly, that this action it performs not, till the body be first sufficiently heated, as we find requisite also to the dissolution of many other bodies by several other menstruums.

Thirdly, that this action of dissolution, produces or generates a very great heat, and that which we call Fire; and this is common also to many dissolutions of other bodies, made by menstruums, of which I could give multitudes of Instances.

Fourthly, that this action is perform'd with so great a violence, and does so minutely act, and rapidly agitate the smallest parts of the combustible matter, that it produces in the diaphanous medium of the Air, the action or pulse of light, which what it is, I have else-where already shewn.

Fifthly, that the dissolution of sulphureous bodies is made by a substance inherent, and mixt with the Air, that is like, if not the very same, with that which is fixt in Salt-peter, which by multitudes of Experiments that may be made with Saltpeter, will, I think, most evidently be demonstrated.

Sixthly, that in this dissolution of bodies by the Air, a certain part is united and mixt, or dissolv'd and turn'd into the Air, and made to fly up and down with it in the same manner as a metalline or other body dissolved into any menstruums, does follow the motions and progresses of that menstruum till it be precipitated.

Seventhly, That as there is one part that is dissoluble by the Air, so are there other parts with which the parts of the Air mixing and uniting, do make a Coagulum, or precipitation, as one may call it, which causes it to be separated from the Air, but this precipitate is so light, and in so small and rarify'd or porous clusters, that it is very volatil, and is easily carry'd up by the motion of the Air, though afterwards, when the heat and agitation that kept it rarify'd ceases, it easily condenses, and commixt with other indissoluble parts, it sticks and adheres to the next bodies it meets withall; and this is a certain Salt that may be extracted out of Soot.

Eighthly, that many indissoluble parts being very apt and prompt to be rarify'd, and so, whilest they continue in that heat and agitation, are lighter then the Ambient Air, are thereby thrust and carry'd upwards with great violence, and by that means carry along with them, not onely that Saline concrete I mention'd before, but many terrestrial, or indissoluble and irrarefiable parts, nay, many parts also which are dissoluble, but are not suffer'd to stay long enough in a sufficient heat to make them prompt and apt for that action. And therefore we find in Soot, not onely a part, that being continued longer in a competent heat, will be dissolv'd by the Air, or take fire and burn; but a part also which is fixt, terrestrial, and irrarefiable.

Ninthly, that as there are these several parts that will rarifie and fly, or be driven up by the heat, so are there many others, that as they are indissoluble by the aerial menstruum, so are they of such sluggish and gross parts, that they are not easily rarify'd by heat, and therefore cannot be rais'd by it; the volatility or fixtness of a body seeming to consist only in this, that the one is of a texture, or has component parts that will be easily rarify'd into the form of Air, and the other, that it has such as will not, without much ado, be brought to such a constitution; and this is that part which remains behind in a white body call'd Ashes, which contains a substance, or Salt, which Chymists call Alkali: what the particular natures of each of these bodies are, I shall not here examine, intending it in another place, but shall rather add that this Hypothesis does so exactly agree with all Phaenomena, of Fire, and so genuinely explicate each particular circumstance that I have hitherto observ'd, that it is more then probable, that this cause which I have assign'd is the true adequate, real, and onely cause of those Phaenomena; And therefore I shall proceed a little further, to shew the nature and use of the Air.

Tenthly, therefore the dissolving parts of the Air are but few, that is, it seems of the nature of those Saline menstruums, or spirits, that have very much flegme mixt with the spirits, and therefore a small parcel of it is quickly glutted, and will dissolve no more; and therefore unless some fresh part of this menstruum be apply'd to the body to be dissolv'd, the action ceases, and the body leaves to be dissolv'd and to shine, which is the Indication of it, though plac'd or kept in the greatest heat; whereas Salt-peter is a menstruum, when melted and red-hot, that abounds more with those Dissolvent particles, and therefore as a small quantity of it will dissolve a great sulphureous body, so will the dissolution be very quick and violent.

Therefore in the Eleventh place, it is observable, that, as in other solutions, if a copious and quick supply of fresh menstruum, though but weak, be poured on, or applied to the dissoluble body, it quickly consumes it: So this menstruum of the Air, if by Bellows, or any other such contrivance, it be copiously apply'd to the shining body, is found to dissolve it as soon, and as violently as the more strong menstruum of melted Nitre.

Therefore twelfthly, it seems reasonable to think that there is no such thing as an Element of Fire that should attract or draw up the flame, or towards which the flame should endeavour to ascend out of a desire or appetite of uniting with that as its Homogeneal primitive and generating Element; but that that shining transient body which we call Flame, is nothing else but a mixture of Air, and volatil sulphureous parts of dissoluble or combustible bodies, which are acting upon each other whilst they ascend, that is, flame seems to be a mixture of Air, and the combustible volatil parts of any body, which parts the encompassing Air does dissolve or work upon, which action, as it does intend the heat of the aerial parts of the dissolvent, so does it thereby further rarifie those parts that are acting, or that are very neer them, whereby they growing much lighter then the heavie parts of that menstruum that are more remote, are thereby protruded and driven upward; and this may be easily observ'd also in dissolution made by any other menstruum, especially such as either create heat or bubbles. Now, this action of the menstruum, or Air, on the dissoluble parts, is made with such violence, or is such, that it imparts such a motion or pulse to the diaphanous parts of the Air, as I have elsewhere shewn is requisite to produce light.

This Hypothesis I have endeavoured to raise from an Infinite of Observations and Experiments, the process of which would be much too long to be here inserted, and will perhaps another time afford matter copious enough for a much larger Discourse, the Air being a Subject which (though all the world has hitherto liv'd and breath'd in, and been unconversant about) has yet been so little truly examin'd or explain'd, that a diligent enquirer will be able to find but very little information from what has been (till of late) written of it: But being once well understood, it will, I doubt not, inable a man to render an intelligible, nay probable, if not the true reason of all the Phaenomena of Fire, which, as it has been found by Writers and Philosophers of all Ages a matter of no small difficulty, as may be sufficiently understood by their strange Hypotheses, and unintelligible Solutions of some few Phaenomena of it; so will it prove a matter of no small concern and use in humane affairs, as I shall elsewhere endeavour to manifest when I come to shew the use of the Air in respiration, and for the preservation of the life, nay, for the conservation and restauration of the health and natural constitution of mankind as well as all other aereal animals, as also the uses of this principle or propriety of the Air in chymical, mechanical, and other operations. In this place I have onely time to hint an Hypothesis, which, if God permit me life and opportunity, I may elsewhere prosecute, improve and publish. In the mean time, before I finish this Discourse, I must not forget to acquaint the Reader, that having had the liberty granted me of making some trials on a piece of Lignum fossile shewn to the Royal Society, by the eminently Ingenious and Learned Physician, Doctor Ent, who receiv'd it for a Present from the famous Ingenioso Cavalliero de Pozzi, it being one of the fairest and best pieces of Lignum fossile he had seen; Having (I say) taken a small piece of this Wood, and examin'd it, I found it to burn in the open Air almost like other Wood, and insteed of a resinous smoak or fume, it yielded a very bituminous one, smelling much of that kind of sent: But that which I chiefly took notice of, was, that cutting off a small piece of it, about the bigness of my Thumb, and charring it in a Crucible with Sand, after the manner I above prescrib'd, I found it infinitely to abound with the smaller sort of pores, so extreamly thick, and so regularly perforating the substance of it long-ways, that breaking it off a-cross, I found it to look very like an Honey-comb; but as for any of the second, or bigger kind of pores, I could not find that it had any; so that it seems, whatever were the cause of its production, it was not without those small kind of pores which we have onely hitherto found in Vegetable bodies: and comparing them with the pores which I have found in the Charcoals that I by this means made of several other kinds of Wood, I find it resemble none so much as those of Fire, to which it is not much unlike in grain also, and several other proprieties.

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 encompassing 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 quantity then elsewhere) are by reason of their being encompassed 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:

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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 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.

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 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 31/4 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, 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 interstitia, 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 transmutation 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 Shell 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 Shells seem'd to be left, but for the most part, those impressions seem'd to be made by an imperfect or broken Shell, the great end or mouth of the Shell 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 Shell; some of them seem'd to be made by such a Shell 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 Shell, 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 Cockle 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 shining 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 Shells; some of them had very large pieces of the Shell 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 Shell, 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 partitions, which seem'd to divide the cavity of the Shell into a multitude 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 Shells 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 shelly moulds into those shaped substances we now find them; that the great and thin end of these Shells 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 Shells which are thus spirallied and separated with Diaphragmes, were some kind of Nautili or Porcelane shells; and that others were shells of Cockles, Muscles, Periwincles, Scolops, &c. of various sorts; that these Shells 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 Shells, 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 Shell 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 Cockle, Muscle, Periwincle, and other shells, which I have found by the Sea side. Nay, further, that some parts of the same Shell 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 Shells, and perhaps all these differing from the encompassing 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 Shells, which are commonly found on the Sea shore: 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 circumstances 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, circumstances, 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 multitudes of other, whereof mention is made in Aldonandus, Wormius, and other Writers of Minerals.

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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 Glass, 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 Interstitia, or walls (as I may so call them) or partitions 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 constitute the sexangular 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 quantity 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 passage out, without suffering the least bubble to pass 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 space? Our Microscope will easily inform us, that the whole mass 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 restitution. 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 assure 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 constitute 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 flourishing 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 constitution 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 Interstitia 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 analogus 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 crassus, cortex superior densus carnosus, duos digitos crassus, 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 encompassing 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 passage 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 pass 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.

Now, though I have with great diligence endeavoured to find whether there be any such thing in those Microscopical pores of Wood or Piths, as the Valves in the heart, veins, and other passages of Animals, that open and give passage to the contain'd fluid juices one way, and shut themselves, and impede the passage of such liquors back again, yet have I not hitherto been able to say any thing positive in it; though, me thinks, it seems very probable, that Nature has in these passages, as well as in those of Animal bodies, very many appropriated Instruments and contrivances, whereby to bring her designs and end to pass, which 'tis not improbable, but that some diligent Observer, if help'd with better Microscopes, may in time detect.

And that this may be so, seems with great probability to be argued from the strange Phaenomena of sensitive Plants, wherein Nature seems to perform several Animal actions with the same Schematism or Orginization that is common to all Vegetables, as may appear by some no less instructive then curious Observations that were made by divers Eminent Members of the Royal Society on some of these kind of Plants, whereof an account was delivered in to them by the most Ingenious and Excellent Physician, Doctor Clark, which, having that liberty granted me by that most Illustrious Society, I have hereunto adjoyn'd.

Observations on the Humble and Sensible Plants in M Chiffin's Garden in Saint James's Park, made August the 9th, 1661. Present, the Lord Brouncker, Sr. Robert Moray, Dr. Wilkins, Mr. Evelin, Dr. Henshaw, and Dr. Clark.

There are four Plants, two of which are little shrub Plants, with a little short stock, about an Inch above the ground, from whence are spread several sticky branches, round, streight, and smooth in the distances between the Sprouts, but just under the Sprouts there are two sharp thorny prickles, broad in the letting on, as in the Bramble, one just under the Sprout, the other on the opposite side of the branch.

[14]The distances betwixt the Sprouts are usually something more then an Inch, and many upon a Branch, according to its length, and they grew so, that if the lower Sprout be on the left side of the Branch, the next above is on the right, and so to the end, not sprouting by pairs.

At the end of each Sprout are generally four sprigs, two at the Extremity, and one on each side, just under it. At the first sprouting of these from the Branch to the Sprig where the leaves grow, they are full of little short white hairs, which wear off as the leaves grow, and then they are smooth as the Branch.

Upon each of these sprigs, are, for the most part, eleven pair of leaves, neatly set into the uppermost part of the little sprig, exactly one against another, as it were in little articulations, such as Anatomists call Enarthrosis, where the round head of a Bone is received into another fitted for its motion; and standing very fitly to shut themselves and touch, the pairs just above them closing somewhat upon them, as in the shut sprig; so is the little round Pedunculus of this leaf fitted into a little cavity of the sprig, visible to the eye in a sprig new pluck'd, or in a sprig withered on the Branch, from which the leaves easily fall by touching.

The leaf being almost an oblong square, and set into the Pedunculus, at one of the lower corners, receiveth from that not onely a Spine, as I may call it, which, passing through the leaf, divides it so length-ways that the outer-side is broader then the inner next the sprig, but little fibres passing obliquely towards the opposite broader side, seem to make it here a little muscular, and fitted to move the whole leaf, which, together with the whole sprig, are set full with little short whitish hairs.

One of these Plants, whose branch seem'd to be older and more grown then the other, onely the tender Sprouts of it, after the leaves are shut, fall and hang down; of the other, the whole branches fall to the ground, if the Sun shine very warm, upon the first taking off the Glass, which I therefore call the humble Plant.

The other two, which do never fall, nor do any of their branches flagg and hang down, shut not their leaves, but upon somewhat a hard stroke; the stalks seem to grow up from a root, and appear more herbaceous, they are round and smooth, without any prickle, the Sprouts from them have several pairs of sprigs, with much less leaves then the other on them, and have on each sprig generally seventeen pair.

Upon touching any of the sprigs with leaves on, all the leaves on that sprig contracting themselves by pairs, joyned their upper superficies close together.

Upon the dropping a drop of Aqua fortis on the sprig betwixt the leaves, ff all the leaves above shut presently, those below by pairs successively after, and by the lower leaves of the other branches, ll, kk, &c. and so every pair successively, with some little distance of time betwixt, to the top of each sprig, and so they continu'd shut all the time we were there. But I returning the next day, and several days since, found all the leaves dilated again on two of the sprigs; but from ff, where the Aqua fortis had dropped upwards, dead and withered; but those below on the same sprig, green, and closing upon the touch, and are so to this day, August 14.

With a pair of Scissers, as suddenly as it could be done, one of the leaves bb was clipped off in the middle, upon which that pair, and the pair above, closed presently, after a little interval, dd, then ee, and so the rest of the pairs, to the bottom of the sprig, and then the motion began in the lower pairs, ll, on the other sprigs, and so shut them by pairs upwards, though not with such distinct distances.

Under a pretty large branch with its sprigs on, there lying a large Shell betwixt two and three Inches below it, there was rubbed on a strong sented oyl, after a little time all the leaves on that sprig were shut, and so they continued all the time of our stay there, but at my returne the next day, I found the position of the Shell alter'd, and the leaves expanded as before, and closing upon the touch.

Upon the application of the Sun-beams by a Burning-glass, the more humble Plant fell, the other shut their leaves.

We could not so apply the smoak of Sulpher, as to have any visible effect from that, at two or three times trial; but on another trial, the smoak touching the leaves, it succeeded.

The humble Plant fell upon taking off the Glass wherewith it was covered.

Cutting off one of the little Sprouts, two or three drops of liquor were thrust out of the part from whence that was cut, very cleer, and pellucid, of a bright greenish colour, tasting at first a little bitterish, but after leaving a licorish-like taste in my mouth.

Since, going two or three times when it was cold, I took the Glasses from the more humble Plant, and it did not fall as formerly, but shut its leaves onely. But coming afterwards, when the Sun shone very warm, as soon as it was taken off, it fell as before.

Since I pluck'd off another sprig, whose leaves were all shut, and had been so some time, thinking to observe the liquor should come from that I had broken off, but finding none, though with pressing, to come, I, as dexterously as I could, pull'd off one whose leaves were expanded, and then had upon the shutting of the leaves, a little of the mention'd liquor, from the end of the sprig I had broken from the Plant. And this twice successively, as often almost as I durst rob the Plant.

But my curiosity carrying me yet further, I cut off one of the harder branches of the stronger Plant, and there came of the liquor, both from that I had cut, and that I had cut it from, without pressure.

Which made me think, that the motion of this Plant upon touching, might be from this, that there being a constant intercourse betwixt every part of this Plant and its root, either by a circulation of this liquor, or a constant pressing of the subtiler parts of it to every extremity of the Plant. Upon every pressure, from whatsoever it proceeds, greater then that which keeps it up, the subtile parts of this liquor are thrust downwards, towards its articulations of the leaves, where, not having room presently to get into the sprig, the little round pedunculus, from whence the Spine and those oblique Fibres I mentioned rise, being dilated, the Spine and Fibres (being continued from it) must be contracted and shortned, and so draw the leaf upwards to joyn with its fellow in the same condition with it self, where, being closed, they are held together by the implications of the little whitish hair, as well as by the still retreating liquor, which distending the Fibres that are continued lower to the branch and root, shorten them above; and when the liquor is so much forced from the Sprout, whose Fibres are yet tender, and not able to support themselves, but by that tensness which the liquor filling their interstices gives them, the Sprout hangs and flags.

But, perhaps, he that had the ability and leisure to give you the exact Anatomy of this pretty Plant, to shew you its Fibres, and visible Canales, through which this fine liquor circulateth, or is moved, and had the faculty of better and more copiously expressing his Observations and conceptions, such a one would easily from the motion of this liquor, solve all the Phaenomena, and would not fear to affirm, that it is no obscure sensation this Plant hath. But I have said too much, I humbly submit, and am ready to stand corrected.

I have not yet made so full and satisfactory Observations as I desire on this Plant, which seems to be a Subject that will afford abundance of information. But as farr as I have had opportunity to examine it, I have discovered with my Microscope very curious structures and contrivances; but designing much more accurate examinations and trials, both with my Microscope, and otherwise, as soon as the season will permit, I shall not till then add any thing of what I have already taken notice of; but as farr as I have yet observ'd, I judge the motion of it to proceed from causes very differing from those by which Gut-strings, or Lute-strings, the beard of a wilde Oat, or the beard of the Seeds of Geranium, Mosscatum, or Musk-grass and other kinds of Cranes-bill, move themselves. Of which I shall add more in the subsequent Observations on those bodies.

* * * * *

Observ. XIX. Of a Plant growing in the blighted or yellow specks of Damask-rose-leaves, Bramble-leaves, and some other kind of leaves.

I have for several years together, in the Moneths of June, July, August, and September (when any of the green leaves of Roses begin to dry and grow yellow) observ'd many of them, especially the leaves of the old shrubs of Damask Roses, all bespecked with yellow stains; and the undersides just against them, to have little yellow hillocks of a gummous substance, and several of them to have small black spots in the midst of those yellow ones, which, to the naked eye, appear'd no bigger then the point of a Pin, or the smallest black spot or tittle of Ink one is able to make with a very sharp pointed Pen.

Examining these with a Microscope, I was able plainly to distinguish, up and down the surface, several small yellow knobs, of a kind of yellowish red gummy substance, out of which I perceiv'd there sprung multitudes of little cases or black bodies like Seed-cods, and those of them that were quite without the hillock of Gumm, disclos'd themselves to grow out of it with a small Straw-colour'd and transparent stem, the which seed and stem appear'd very like those of common Moss (which I elsewhere describe) but that they were abundantly less, many hundreds of them being not able to equalize one single seed Cod of Moss.

I have often doubted whether they were the seed Cods of some little Plant, or some kind of small Buds, or the Eggs of some very small Insect, they appear'd of a dark brownish red, some almost quite black, and of a Figure much resembling the seed-cod of Moss, but their stalks on which they grew were of a very fine transparent substance, almost like the stalk of mould, but that they seem'd somewhat more yellow.

That which makes me to suppose them to be Vegetables, is for that I perceiv'd many of those hillocks bare or destitute, as if those bodies lay yet conceal'd, as G. In others of them, they were just springing out of their gummy hillocks, which all seem'd to shoot directly outwards, as at A. In others, as at B, I found them just gotten out, with very little or no stalk, and the Cods of an indifferent cize; but in others, as C, I found them begin to have little short stalks, or stems; in others, as D, those stems were grown bigger, and larger; and in others, as at E, F, H, I, K, L, &c. those stems and Cods were grown a great deal bigger, and the stalks were more bulky about the root, and very much taper'd towards the top, as at F and L is most visible.

I did not find that any of them had any seed in them, or that any of them were hollow, but as they grew bigger and bigger, I found those heads or Cods begin to turn their tops towards their roots, in the same manner as I had observ'd that of Moss to do; so that in all likelihood, Nature did intend in that posture, what she does in the like seed-cods of greater bulk, that is, that the seed, when ripe, should be shaken out and dispersed at the end of it, as we find in Columbine Cods, and the like.

The whole Oval OOOO in the second Figure of the 12. Scheme represents a small part of a Rose leaf, about the bigness of the little Oval in the hillock, C, marked with the Figure X. in which I have not particularly observ'd all the other forms of the surface of the Rose-leaf, as being little to my present purpose.

Now, if these Cods have a seed in them so proportion'd to the Cod, as thole of Pinks, and Carnations, and Columbines, and the like, how unimaginably small must each of those seeds necessarily be, for the whole length of one of the largest of those Cods was not 1/500 part of an Inch; some not above 1/1000, and therefore certainly, very many thousand of them would be unable to make a bulk that should be visible to the naked eye; and if each of these contain the Rudiments of a young Plant of the same kind, what must we say of the pores and constituent parts of that?

The generation of this Plant seems in part, ascribable to a kind of Mildew or Blight, whereby the parts of the leaves grow scabby, or putrify'd, as it were, so as that the moisture breaks out in little scabs or spots, which, as I said before, look like little knobs of a red gummous substance.

From this putrify'd scabb breaks out this little Vegetable; which may be somewhat like a Mould or Moss; and may have its equivocal generation much after the same manner as I have supposed Moss or Mould to have, and to be a more simple and uncompounded kind of vegetation, which is set a moving by the putrifactive and fermentative heat, joyn'd with that of the ambient aerial, when (by the putrifaction and decay of some other parts of the vegetable, that for a while staid its progress) it is unfetter'd and left at liberty to move in its former course, but by reason of its regulators, moves and acts after quite another manner then it did when a coagent in the more compounded machine of the more perfect Vegetable.

And from this very same Principle, I imagine the Misleto of Oaks, Thorns, Appletrees, and other Trees, to have its original: It seldom or never growing on any of those Trees, till they begin to wax decrepid, and decay with age, and are pester'd with many other infirmities.

Hither also may be referr'd those multitudes and varieties of Mushroms, such as that, call'd Jews-ears, all sorts of gray and green Mosses, &c. which infest all kind of Trees, shrubs, and the like, especially when they come to any bigness. And this we see to be very much the method of Nature throughout its operations, putrifactive Vegetables very often producing a Vegetable of a much less compounded nature, and of a much inferiour tribe; and putrefactive animal substances degenerating into some kind of animal production of a much inferiour rank, and of a more simple nature.

Thus we find the humours and substances of the body, upon putrifaction, to produce strange kinds of moving Vermine: the putrifaction of the slimes and juices of the Stomack and Guts, produce Worms almost like Earth-worms, the Wheals in childrens hands produce a little Worm, call'd a Wheal-worm: The bloud and milk, and other humours, produce other kinds of Worms, at least, if we may believe what is deliver'd to us by very famous Authors; though, I confess, I have not yet been able to discover such my self.

And whereas it may seem strange that Vinegar, Meal, musty Casks, &c. are observ'd to breed their differing kinds of Insects, or living creatures, whereas they being Vegetable substances, seem to be of an inferiour kind, and so unable to produce a creature more noble, or of a more compounded nature then they themselves are of, and so without some concurrent seminal principle, may be thought utterly unfit for such an operation; I must add, that we cannot presently positively say, there are no animal substances, either mediately, as by the soil or fatning of the Plant from whence they sprung, or more immediately, by the real mixture or composition of such substances, join'd with them; or perchance some kind of Insect, in such places where such kind of putrifying or fermenting bodies are, may, by a certain instinct of nature, eject some sort of seminal principle, which cooperating with various kinds of putrifying substances, may produce various kinds of Insects, or Animate bodies: For we find in most sorts of those lower degrees of Animate bodies, that the putrifying substances on which these Eggs, Seeds, or seminal principles are cast by the Insect, become, as it were, the Matrices or Wombs that conduce very much to their generation, and may perchance also to their variation and alteration, much after the same manner, as, by strange and unnatural copulations, several new kinds of Animals are produc'd, as Mules, and the like, which are usually call'd Monstrous, because a little unusual, though many of them have all their principal parts as perfectly shap'd and adapted for their peculiar uses, as any of the most perfect Animals. If therefore the putrifying body, on which any kind of seminal or vital principle chances to be cast, become somewhat more then meerly a nursing and fostering helper in the generation and production of any kind of Animate body, the more neer it approaches the true nature of a Womb, the more power will it have on the by-blow it incloses. But of this somewhat more in the description of the Water-gnat. Perhaps some more accurate Enquiries and Observations about these matters might bring the Question to some certainty, which would be of no small concern in Natural Philosophy.

But that putrifying animal substances may produce animals of an inferior kind, I see not any so very great a difficulty, but that one may, without much absurdity, admit: For as there may be multitudes of contrivances that go to the making up of one compleat Animate body; so, That some of those coadjutors, in the perfect existence and life of it, may be vitiated, and the life of the whole destroyed, and yet several of the constituting contrivances remain intire, I cannot think it beyond imagination or possibility; no more then that a like accidental process, as I have elswhere hinted, may also be supposed to explicate the method of Nature in the Metamorphosis of Plants. And though the difference between a Plant and an Animal be very great, yet I have not hitherto met with any so cogent an Argument, as to make me positive in affirming these two to be altogether Heterogeneous and of quite differing kinds of Nature: And besides, as there are many Zoophyts, and sensitive Plants (divers of which I have seen, which are of a middle nature, and seem to be Natures transition from one degree to another, which may be observ'd in all her other passages, wherein she is very seldom observ'd to leap from one step to another) so have we, in some Authors, Instances of Plants turning into Animals, and Animals into Plants, and the like; and some other very strange (because unheeded) proceedings of Nature; something of which kind may be met with, in the description of the Water-Gnat, though it be not altogether so direct to the present purpose.

But to refer this Discourse of Animals to their proper places, I shall add, that though one should suppose, or it should be prov'd by Observations; that several of these kinds of Plants are accidentally produc'd by a casual purifaction, I see not any great reason to question, but that, notwithstanding its own production was as 'twere casual, yet it may germinate and produce seed, and by it propagate its own, that is, a new Species. For we do not know, but that the Omnipotent and All-wise Creator might as directly design the structure of such a Vegetable, or such an Animal to be produc'd out of such or such a putrifaction or change of this or that body, towards the constitution or structure of which, he knew it necessary, or thought it fit to make it an ingredient; as that the digestion or moderate heating of an Egg, either by the Female, or the Sun, or the heat of the Fire, or the like, should produce this or that Bird; or that Putrifactive and warm steams should, out of the blowings, as they call them, that is, the Eggs of a Flie, produce a living Magot, and that, by degrees, be turn'd into an Aurelia, and that, by a longer and a proportion'd heat, be transmuted into a Fly. Nor need we therefore to suppose it the more imperfect in its kind, then the more compounded Vegetable or Animal of which it is a part; for he might as compleatly furnish it with all kinds of contrivances necessary for its own existence, and the propagation of its own Species, and yet make it a part of a more compounded body: as a Clock-maker might make a Set of Chimes to be a part of a Clock, and yet, when the watch part or striking part are taken away, and the hindrances of its motion remov'd, this chiming part may go as accurately, and strike its tune as exactly, as if it were still a part of the compounded Automaton. So, though the original cause, or seminal principle from which this minute Plant on Rose leaves did spring; were, before the corruption caus'd by the Mill-dew, a component part of the leaf on which it grew, and did serve as a coagent in the production and constitution of it, yet might it be so consummate, as to produce a seed which might have a power of propagating the same species: the works of the Creator seeming of such an excellency, that though they are unable to help to the perfecting of the more compounded existence of the greater Plant or Animal, they may have notwithstanding an ability of acting singly upon their own internal principle, so as to produce a Vegetable body, though of a less compounded nature, and to proceed so farr in the method of other Vegetables, as to bear flowers and seeds, which may be capabale of propagating the like. So that the little cases which appear to grow on the top of the slender stalks, may, for ought I know, though I should suppose them to spring from the perverting of the usual course of the parent Vegetable, contain a seed, which, being scatter'd on other leaves of the same Plant, may produce a Plant of much the same kind.