Micrographia — Observ. XV.

Observ.

XV.

_Of _Kettering-stone_, and of the pores of _Inanimate_ bodies.

_ [13]This Stone which is brought from _Kettering_ in _Northampton-Shire_, and digg’d out of a Quarry, as I am inform’d, has a grain altogether admirable, nor have I ever seen or heard of any other stone that has the like.

It is made up of an innumerable company of small bodies, not all of the same cize or shape, but for the most part, not much differing from a Globular form, nor exceed they one another in Diameter above three or four times; they appear to the eye, like the Cobb or Ovary of a _Herring_, or some smaller fishes, but for the most part, the particles seem somewhat less, and not so uniform; but their variation from a perfect globular ball, seems to be only by the pressure of the _contiguous_ bals which have a little deprest and protruded those toucht sides inward, and forc’d the other sides as much outwards beyond the limits of a Globe; just as it would happen, if a heap of exactly round Balls of soft Clay were heaped upon one another; or, as I have often seen a heap of small Globules of _Quicksilver_, reduc’d to that form by rubbing it much in a glaz’d Vessel, with some slimy or sluggish liquor, such as Spittle, when though the top of the upper Globules be very neer spherical, yet those that are prest upon by others, exactly imitate the forms of these lately mention’d grains.

Where these grains touch each other, they are so firmly united or settled together, that they seldom part without breaking a hole in one or th’other of them, such as a, a, a, b, c, c, &c. Some of which fractions, as a, a, a, a, where the touch has been but light, break no more then the outward crust, or first shell of the stone, which is of a white colour, a little dash’d with a brownish Yellow, and is very thin, like the shell of an Egg: and I have seen some of those grains perfectly resemble some kind of Eggs, both in colour and shape: But where the union of the _contiguous granules_ has been more firm, there the divulsion has made a greater Chasm, as at b, b, b, in so much that I have observ’d some of them quite broken in two, as at c, c, c, which has discovered to me a further resemblance they have to Eggs, they having an appearance of a white and yelk, by two differing substances that envelope and encompass each other.

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 _æthereal_ 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 _Mechanisms_ 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 _Phænomena_ 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 manner (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 easily 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 nearly approach to the nature and manner of the air’s being dissolv’d by this fluid or _Æther_.

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 _Æther_ 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 _Æther_ 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 5²⁰⁹⁄₂₅₆ _Grains_.

The same put under water for a night, and somewhat more, became transparent, and the superficies being wiped dry, weighed 6³⁄₂₅₆ _Grains_.

The difference between these two weights, 0⁵⁰⁄₂₅₆ of a _Grain_.

The same Stone kept out of water one Day and becoming cloudy again weighed, 5²²⁵⁄₂₅₆ _Graines_.

Which was more then the first weight, 0¹⁶⁄₂₅₆ of a _Grain_.

The same being kept two Days longer weighed, 5²⁰²⁄₂₅₆ _Graines_.

Which was less then at first, 0⁷⁄₂₅₆ 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, _6³⁄₂₅₆ Grains_, the same with the first after putting in water, and more then the last weight after keeping of it dry, 0⁵⁷⁄₂₅₆ 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 18⁹⁷⁄₁₂₈ _Graines_.

After it had lyen in about four and twenty hours the weight was 20²⁷⁄₁₂₈ _Graines_, so the difference was, 1⁵⁸⁄₁₂₈ _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 _Phænomena_, 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 _Phænomena_, 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 _Phænomena_ 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_.