Micrographia — Observ. VI. (part 2)

This therefore being thus explained, there will be divers _Phænomena_ explicable thereby, as, the rising of _Liquors_ in a _Filtre_, the rising of _Spirit of Wine_, _Oyl_, _melted Tallow_, &c. in the _Week_ of a _Lamp_, (though made of small _Wire_, _Threeds_ of _Asbestus_, _Strings_ of _Glass_, or the like) the rising of _Liquors_ in a _Spunge_, piece of _Bread_, _Sand_, &c. perhaps also the ascending of the _Sap_ in _Trees_ and _Plants_, through their small, and some of them _imperceptible pores_, (of which I have said more, on another occasion) at least the passing of it out of the earth into their roots.

And indeed upon the consideration of this Principle, multitudes of other uses of it occurr’d to me, which I have not yet so well examined and digested as to propound for _Axioms_, but only as _Queries_ and _Conjectures_ which may serve as _hints_ toward some further _discoveries_.

As first, Upon the consideration of the _congruity_ and _incongruity_ of Bodies, as to _touch_, I found also the like _congruity_ and _incongruity_ (if I may so speak) as to the _Transmitting_ of the _Rates_ of Light: For as in this regard, _water_ (not now to mention other Liquors) seems nearer of affinity to _Glass_ then _Air_, and _Air_ then _Quicksilver_: whence an _oblique Ray_ out of _Glass_, will pass into _water_ with very little _refraction_ from the _perpendicular_, but none out of _Glass_ into _Air_, excepting a _direct_, will pass without a very great refraction from the perpendicular, nay any oblique Ray under thirty degrees, will not be admitted into the Air at all.

And _Quicksilver_ will neither admit oblique or direct, but reflects all; seeming, as to the transmitting of the Raies of Light, to be of a quite differing constitution, from that of _Air_, _Water_, _Glass_, &c. and to resemble most those opacous and strong reflecting bodies of Metals: So also as to the property of cohesion or congruity, Water seems to keep the same order, being more congruous to Glass then Air, and Air then Quicksilver.

A Second thing (which was hinted to me, by the consideration of the included fluids globular form, caused by the protrusion of the ambient heterogeneous fluid) was, whether the _Phænomena_ of gravity might not by this means be explained, by supposing the _Globe_ of Earth, Water, and Air to be included with a _fluid_, heterogeneous to all and each of them, so subtil, as not only to be every where _interspersed_ through the _Air_, (or rather the _air_ through it) but to _pervade_ the bodies of _Glass_, and even the _closest Metals_, by which means it may endeavour to _detrude_ all earthly bodies as far from it as it can; and partly thereby, and partly by other of its properties may move them towards the Center of the Earth.

Now that there is some such fluid, I could produce many Experiments and Reasons, that do seem to prove it: But because it would ask some time and room to set them down and explain them, and to consider and answer all the Objections (many whereof I foresee) that may be alledged against it; I shall at present proceed to other _Queries_, contenting my self to have here only given a hint of what I may say more elswhere.

A Third _Query_ then was, Whether the _heterogeneity_ of the _ambient fluid_ may not be accounted a _secondary cause_ of the _roundness_ or _globular form_ of the _greater bodies_ of the world, such as are those of the _Sun_, _Stars_, and _Planets_, the _substance_ of each of which seems altogether _heterogeneous_ to the _circumambient fluid æther_?

And of this I shall say more in the Observation of the Moon.

A Fourth was, Whether the _globular form_ of the _smaller parcels_ of matter here upon the _Earth_, as that of _Fruits_, _Pebbles_, or _Flints_, &c. (which seem to have been a _Liquor_ at first) may not be caused by the _heterogeneous ambient fluid_.

For thus we see that melted _Glass_ will be naturally formed into a _round Figure_; so likewise any small Parcel of any _fusible body_, if it be perfectly enclosed by the _Air_, will be driven into a _globular_ Form; and, when cold, will be found a _solid Ball_.

This is plainly enough manifested to us by their way of making _shot_ with the _drops of Lead_; which being a very pretty curiosity, and known but to a very few, and having the liberty of publishing it granted me, by that _Eminent Virtuoso_ Sir _Robert Moray_, who brought in this Account of it to the _Royal Society_, I have here transcribed and inserted.

To make small shot of different sizes; Communicated by his Highness _P.

R.

_ _Take Lead out of the Pig what quantity you please, melt it down, stir and clear it with an iron Ladle, gathering together the blackish parts that swim at top like scum, and when you see the colour of the clear Lead to be greenish, but no sooner, strew upon it _Auripigmentum_ powdered according to the quantity of Lead, about as much as will lye upon a half Crown piece will serve for eighteen or twenty pound weight of some sorts of Lead;

others will require more, or less.

After the _Auripigmentum_ is put in, stir the Lead well, and the _Auripigmentum_ will flame: when the flame is over, take out some of the Lead in a Ladle having a lip or notch in the brim for convenient pouring out of the Lead, and being well warmed amongst the melted Lead, and with a stick make some single drops of Lead trickle out of the Ladle into water in a Glass, which if they fall to be round and without tails, there is _Auripigmentum_ enough put in, and the temper of the heat is right, otherwise put in more.

Then lay two bars of Iron (or some more proper Iron-tool made on purpose) upon a Pail of water, and place upon them a round Plate of Copper, of the size and figure of an ordinary large Pewter or Silver Trencher, the hollow whereof is to be about three inches over, the bottom lower then the brims about half an inch, pierced with thirty, forty, or more small holes; the smaller the holes are, the smaller the shot will be; and the brim is to be thicker then the bottom, to conserve the heat the better.

_ _The bottom of the Trencher being some four inches distant from the water in the Pail, lay upon it some burning Coles, to keep the Lead melted upon it.

Then with the hot Ladle take Lead off the Pot where it stands melted, and pour it softly upon the burning Coles over the bottom of the Trencher, and it will immediately run through the holes into the water in small round drops.

Thus pour on new Lead still as fast as it runs through the Trencher till all be done; blowing now and then the Coles with hand-Bellows, when the Lead in the Trencher cools so as to stop from running.

_ _Whilst one pours on the Lead, another must, with another Ladle, thrusted four or five inches under water in the Pail, catch from time to time some of the shot, as it drops down, to see the size of it, and whether there be any faults in it.

The greatest care is to keep the Lead upon the Trencher in the right degree of heat; if it be too cool, it will not run through the Trencher, though it stand melted upon it; and this is to be helped by blowing the Coals a little, or pouring on new Lead that is hotter: but the cooler the Lead, the larger the Shot; and the hotter, the smaller; when it is too hot, the drops will crack and fly; then you must stop pouring on new Lead, and let it cool; and so long as you observe the right temper of the heat, the Lead will constantly drop into very round Shot, without so much as one with a tail in many pounds.

_ _When all is done, take your Shot out of the Pail of water, and put it in a Frying-pan over the fire to dry them, which must be done warily, still shaking them that they melt not; and when they are dry you may separate the small from the great, in Pearl Sives made of Copper or Lattin let into one another, into as many sizes at you please.

But if you would have your Shot larger then the Trencher makes them, you may do it with a Stick, making them trickle out of the Ladle, as hath been said.

_ _If the Trencher be but toucht a very little when the Lead stops from going through it, and be not too cool, it will drop again, but it is better not to touch it at all.

At the melting of the Lead take care that there be no kind of Oyl, Grease, or the like, upon the Pots, or Ladles, or Trencher.

_ _The Chief cause of this Globular Figure of the Shot, seems to be the _Auripigmentum_; for, as soon as it is put in among the melted Lead, it loses its shining brightness, contracting instantly a grayish film or skin upon it, when you scum it to make it clean with the Ladle.

So that when the Air comes at the falling drop of the melted Lead, that skin constricts them every where equally: but upon what account, and whether this be the true cause, is left to further disquisition.

_ Much after this same manner, when the Air is exceeding cold through which it passes; do we find the drops of Rain, falling from the Clouds, congealed into round Hail-stones by the freezing Ambient.

To which may be added this other known Experiment, That if you gently let fall a drop of _water_ upon small _sand_ or _dust_, you shall find, as it were, an artificial _round stone_ quickly generated.

I cannot upon this occasion omit the mentioning of the strange kind of _Grain_, which I have observed in a _stone_ brought from _Kettering_ in _Northamptonshire_, and therefore called by Masons _Kettering-Stone_, of which see the Description.

Which brings into my mind what I long since observed in the fiery Sparks that are struck out of a Steel.

For having a great desire to see what was left behind, after the Spark was gone out, I purposely struck fire over a very white piece of Paper, and observing diligently where some conspicuous sparks went out, I found a very little black spot no bigger then the point of a Pin, which through a _Microscope_ appeared to be a perfectly round Ball, looking much like a polisht ball of Steel, insomuch that I was able to see the Image of the window reflected from it.

I cannot here stay (having done it more fully in another place) to examine the particular Reasons of it, but shall only hint, that I imagine it to be some small parcel of the Steel, which by the violence of the motion of the stroke (most of which seems to be imprest upon those small parcels) is made so glowing hot, that it is melted into a _Vitrum_, which by the ambient Air is thrust into the form of a Ball.

A Fifth thing which I thought worth Examination was, Whether the motion of all kind of Springs, might not be reduced to the Principle whereby the included _heterogeneous fluid_ seems to be moved; or to that whereby two Solids, as Marbles, or the like, are thrust and kept together by the _ambient fluid_.

A Sixth thing was, Whether the Rising and Ebullition of the Water out of Springs and Fountains (which lie much higher from the Center of the Earth then the Superficies of the Sea, from whence it seems to be derived) may not be explicated by the rising of Water in a smaller Pipe: For the Sea-water being strained through the Pores or Crannies of the Earth, is, as it were, included in little Pipes, where the pressure of the Air has not so great a power to resist its rising: But examining this way, and finding in it several difficulties almost irremovable, I thought upon a way that would much more naturally and conceivably explain it, which was by this following Experiment: I took a Glass-Tube, of the form of that described in the sixth Figure, and chusing two _heterogeneous fluids_, such as Water and Oyl, I poured in as much Water as filled up the Pipes as high as AB, then putting in some Oyl into the Tube AC, I deprest the superficies A of the Water to F, and B I raised to G, which was not so high perpendicularly as the superficies of the Oyl F, by the space FI, wherefore the proportion of the gravity of these two Liquors was as GH to FE.

This Experiment I tried with several other Liquors, and particularly with fresh Water and Salt (which I made by dissolving Salt in warm Water) which two though they are nothing heterogeneous, yet before they would perfectly mix one with another, I made trial of the Experiment: Nay, letting the Tube wherein I tried the Experiment remain for many dayes, I observed them not to mix; but the superficies of the fresh was rather more then less elevated above that of the Salt.

Now the proportion of the gravity of Sea-water, to that of River-water, according to _Stevinus_ and _Varenius_, and as I have since found pretty true by making trial my self, is as 46. to 45. that is, 46. Ounces of the salt Water will take up no more room then 45. of the fresh.

Or reciprocally 45 pints of salt-water weigh as much as 46 of fresh.

But I found the proportion of Brine to fresh Water to be near 13 to 12: Supposing therefore GHM to represent the Sea, and FI the height of the Mountain above the Superficies of the Sea, FM a Cavern in the Earth, beginning at the bottom of the Sea, and terminated at the top of the Mountain, LM the Sand at the bottom, through which the Water is as it were strained, so as that the fresher parts are only permitted to transude, and the saline kept back; if therefore the proportion of G M to FM be as 45 to 46, then may the Cylinder of Salt-water GM make the Cylinder of Fresh-water to rise as high as E, and to run over at N. I cannot here stand to examine or confute their Opinion, who make the depth of the Sea, below its Superficies, to be no more perpendicularly measured then the height of the Mountains above it: ’Tis enough for me to say, there is no one of those that have asserted it, have experimentally known the perpendicular of either; nor shall I here determine, whether there may not be many other causes of the separation of the fresh water from the salt, as perhaps some parts of the Earth through which it is to pass, may contain a Salt, that mixing and uniting with the Sea-salt, may precipitate it; much after the same manner as the _Alcalizate_ and _Acid Salts_ mix and precipitate each other in the preparation of _Tartarum Vitriolatum.

_ I know not also whether the exceeding cold (that must necessarily be) at the bottom of the Water, may not help towards this separation, for we find, that warm Water is able to dissolve and contain more Salt, then the same cold; insomuch that Brines strongly impregnated by heat, if let cool, do suffer much of their Salt to subside and crystallize about the bottom and sides.

I know not also whether the exceeding pressure of the parts of the Water one against another, may not keep the Salt from descending to the very bottom, as finding little or no room to insert it self between those parts, protruded so violently together, or else squeeze it upwards into the superiour parts of the Sea, where it may more easily obtain room for it self, amongst the parts of the Water, by reason that there is more heat and less pressure.

To this Opinion I was somewhat the more induced by the relations I have met with in _Geographical Writers_, of drawing fresh Water from the bottom of the Sea, which is salt above.

I cannot now stand to examine, whether this natural perpetual motion may not artificially be imitated: Nor can I stand to answer the Objections which may be made against this my Supposition: As, First, How it comes to pass, that there are sometimes salt Springs much higher then the Superficies of the Water?

And, Secondly, Why Springs do not run faster and slower, according to the varying height made of the Cylinder of Sea-water, by the ebbing and flowing of the Sea?

As to the First, In short, I say, the fresh Water may receive again a saline Tincture near the Superficies of the Earth, by passing through some salt _Mines_, or else many of the saline parts of the Sea may be kept back, though not all.

And as to the Second, The same _Spring_ may be fed and supplyed by divers _Caverns_, coming from very far distant parts of the _Sea_, so as that it may in one place be _high_, in another _low water_; and so by that means the _Spring_ may be equally supply’d at all times.

Or else the _Cavern_ may be so straight and narrow, that the water not having so ready and free passage through it, cannot upon so short and quick mutations of pressure, be able to produce any sensible effect at such a distance.

Besides that, to confirm this _hypothesis_, there are many _Examples_ found in _Natural Historians_, of _Springs_ that do ebb and flow like the Sea: As particularly, those recorded by the Learned _Camden_, and after him by _Speed_, to be found in this _Island_: One of which, they relate to be on the Top of a Mountain, by the small Village _Kilken_ in _Flintshire_, _Maris æmulus qui statis temporibus suas evomit & resorbet Aquas_; Which at certain times riseth and falleth after the manner of the Sea.

A Second in _Caermardenshire_, near _Caermarden_, at a place called _Cantred Bichan_;

_Qui (ut scribit Giraldus) naturali die bis undis deficiens, & toties exuberans, marinas imitatur instabilitates_; That twice in four and twenty hours ebbing and flowing; resembleth the unstable motions of the Sea.

The _Phænomena_ of which two may be easily made out, by supposing the _Cavern_, by which they are fed, to arise from the bottom of the next Sea.

A Third, is a Well upon the River _Ogmore_ in _Glamorganshire_, and near unto _Newton_, of which _Camden_ relates himself to be certified, by a Letter from a Learned Friend of his that observed it, _Fons abest hinc, &c. _ The Letter is a little too long to be inserted, but the substance is this; That this Well ebbs and flows quite contrary to the flowing and ebbing of the Sea in those parts: for ’tis almost empty at Full Sea, but full at Low water.

This may happen from the Channel by which it is supplied, which may come from the bottom of a Sea very remote from those parts, and where the Tides are much differing from those of the approximate shores.

A Fourth, lies in _Westmorland_, near the River _Leder_; _Qui instar Euripi sæpius in die reciprocantibus undis fluit & refluit_, which ebbs and flows many times a day.

This may proceed from its being supplyed from many Channels, coming from several parts of the Sea, lying sufficiently distant asunder to have the times of High water differing enough one from the other; so as that whensoever it shall be High water over any of those places, where these Channels begin, it shall likewise be so in the Well; but this is but a supposition.

A Seventh _Query_ was, Whether the _dissolution_ or mixing of several bodies, whether fluid or solid, with saline or other Liquors, might not partly be attributed to this Principle of the congruity of those bodies and their dissolvents?

As of Salt in Water, Metals in several _Menstruums_, Unctuous Gums in Oyls, the mixing of Wine and Water, &c. And whether _precipitation_ be not partly made from the same Principle of Incongruity?

I say _partly_, because there are in some Dissolutions, some other Causes concurrent.

I shall lastly make a much more seemingly strange and unlikely _Query_; and that is, Whether this Principle, well examined and explained, may not be found a _coefficient_ in the most considerable Operations of Nature?

As in those of _Heat_, and _Light_, and consequently of _Rarefaction_ and _Condensation_, _Hardness_, and _Fluidness_, _Perspicuity_ and _Opacousness_, _Refractions_ and _Colours.

&c. _ Nay, I know not whether there may be many things done in Nature, in which this may not (be said to) have a Finger?

This I have in some other passages of this Treatise further enquired into and shewn, that as well _Light_ as _Heat_ may be caused by _corrosion_, which is applicable to _congruity_, and consequently all the rest will be but _subsequents_: In the mean time I would not willingly be guilty of that _Error_, which the thrice Noble and Learned _Verulam_ justly takes notice of, as such, and calls _Philosophiæ Genus Empiricum, quod in paucorum Experimentorum Angustiis & Obscuritate fundatum est_.

For I neither conclude from one single Experiment, nor are the Experiments I make use of all made upon one Subject: Nor wrest I any Experiment to make it _quadrare_ with any preconceiv’d Notion.

But on the contrary, I endeavour to be conversant in divers kinds of Experiments, and all and every one of those Trials, I make the Standards or Touchstones, by which I try all my former Notions, whether they hold out in weight, and measure, and touch, &c. For as that Body is no other then a Counterfeit Gold, which wants any one of the Proprieties of Gold, (such as are the Malleableness, Weight, Colour, Fixtness in the Fire, Indissolubleness in _Aqua fortis_, and the like) though it has all the other; so will all those Notions be found to be false and deceitful, that will not undergo all the Trials and Tests made of them by Experiments.

And therefore such as will not come up to the desired _Apex_ of Perfection, I rather wholly reject and take new, then by piecing and patching, endeavour to retain the old, as knowing such things at best to be but lame and imperfect.

And this course I learned from Nature; whom we find neglectful of the old Body, and suffering its Decaies and Infirmities to remain without repair, and altogether sollicitous and careful of perpetuating the _Species_ by new _Individuals_.

And it is certainly the most likely way to erect a glorious Structure and Temple to _Nature_, such as she will be found (by any _zealous Votary_) to reside in;

to begin to build a new upon a sure Foundation of Experiments.

But to digress no further from the consideration of the _Phænomena_, more immediately explicable by this Experiment, we shall proceed to shew, That, as to the rising of Water in a _Filtre_, the reason of it will be manifest to him, that does take notice, that a _Filtre_ is constituted of a great number of small long solid bodies, which lie so close together, that the Air in its getting in between them, doth lose of its pressure that it has against the _Fluid_ without them, by which means the Water or Liquor not finding so strong a resistance between them as is able to counter-ballance the pressure on its superficies without, is raised upward, till it meet with a pressure of the Air which is able to hinder it.

And as to the Rising of Oyl, melted Tallow, Spirit of Wine, &c. in the Week of a Candle or Lamp, it is evident, that it differs in nothing from the former, save only in this, that in a _Filtre_ the Liquor descends and runs away by another part;

and in the Week the Liquor is dispersed and carried away by the Flame;

something there is ascribable to the Heat, for that it may rarifie the more volatil and spirituous parts of those combustible Liquors, and so being made lighter then the Air, it may be protruded upwards by that more ponderous fluid body in the Form of Vapours; but this can be ascribed to the ascension of but a very little, and most likely of that only which ascends without the Week.

As for the Rising of it in a Spunge, Bread, Cotton, &c. above the superficies of the subjacent Liquor, what has been said about the _Filtre_ (if considered) will easily suggest a reason, considering that all these bodies abound with small holes or pores.

From this same Principle also (_viz.

the unequal pressure of the Air against the unequal superficies of the water_) proceeds the cause of the accession or incursion of any floating body against the sides of the containing Vessel; or the _appropinquation_ of two floating bodies, as _Bubbles_, _Corks_, _Sticks_, _Straws_, &c. one towards another.

As for instance, Take a Glass jar, such as AB in the seventh _Figure_, and filling it pretty near the top with water, throw into it a small round piece of Cork, as C, and plunge it all over in water, that it be wet, so as that the water may rise up by the sides of it, then placing it any where upon the superficies, about an inch, or one inch and a quarter from any side, and you shall perceive it by degrees to make _perpendicularly_ toward the nearest part of the side, and the nearer it approaches, the faster to be moved, the reason of which _Phænomenon_ will be found no other then this, that the Air has a greater pressure against the middle of the _superficies_, then it has against those parts that approach nearer, and are _contiguous_ to the sides.

Now that the pressure is greater, may (as I shewed before in the explication of the third _Figure_) be evinced from the flatting of the water in the middle, which arises from the gravity of the under _fluid_: for since, as I shewed before, if there were no gravity in the under _fluid_, or that it were equal to that of the upper, the terminating Surface would be _Spherical_, and since it is the additional pressure of the gravity of water that makes it so flat, it follows, that the pressure upon the middle must be greater then towards the sides.

Hence the Ball having a stronger pressure against that side of it which respects the middle of the _superficies_, then against that which respects the _approximate_ side, must necessarily move towards that part, from whence it finds least resistance, and so be _accelerated_, as the resistance decrease.

Hence the more the water is raised under that part of its way it is passing above the middle, the faster it is moved: And therefore you will find it to move faster in E then in D, and in D then in C. Neither could I find the floating substance to be moved at all, until it were placed upon some part of the _Superficies_ that was sensibly elevated above the height of the middle part.

Now that this may be the true cause, you may try with a blown Bladder, and an exactly round Ball upon a very smooth side of some pliable body, as _Horn_ or _Quicksilver.

_ For if the Ball be placed under a part of the Bladder which is upon one side of the middle of its pressure, and you press strongly against the Bladder, you shall find the Ball moved from the middle towards the sides.

Having therefore shewn the reason of the motion of any float towards the sides, the reason of the incursion of any two floating bodies will easily appear: For the rising of the water against the sides of either of them, is an Argument sufficient, to shew the pressure of the Air to be there less, then it is further from it, where it is not so much elevated; and therefore the reason of the motion of the other toward it, will be the same as towards the side of the Glass, only here from the same reason, they are mutually moved toward each other, whereas the side of the Glass in the former remains fixt.

If also you gently fill the Jar so full with water, that the water is _protuberant_ above the sides, the same piece of Cork that before did hasten towards the sides, does now fly from it as fast towards the middle of the Superficies; the reason of which will be found no other then this, that the pressure of the Air is stronger against the sides of the Superficies G and H, then against the middle I; for since, as I shewed before, the Principle of congruity would make the terminating Surface Spherical, and that the flatting of the Surface in the middle is from the abatement of the waters pressure outwards, by the contrary indeavour of its gravity; it follows that the pressure in the middle must be less then on the sides; and therefore the consecution will be the same as in the former.

It is very odd to one that considers not the reason of it, to see two floating bodies of wood to approach each other, as though they were indued with some magnetical vigour; which brings into my mind what I formerly tried with a piece of Cork or such like body, which I so ordered, that by putting a little stick into the same water, one part of the said Cork would approach and make toward the stick, whereas another would discede and fly away, nay it would have a kind of verticity, so as that if the _Æquator_ (as I may so speak) of the Cork were placed towards the stick, if let alone, it would instantly turn its appropriate Pole toward it, and then run a-tilt at it: and this was done only by taking a dry Cork, and wetting one side of it with one small stroak; for by this means gently putting it upon the water, it would depress the superficies on every side of it that was dry, and therefore the greatest pressure of the Air, being near those sides, caused it either to chase away, or else to fly off from any other floating body, whereas that side only, against which the water ascended, was thereby able to attract.

It remains only, that I should determine how high the Water or other Liquor may by this means be raised in a smaller Pipe above the Superficies of that without it, and at what height it may be sustained: But to determine this, will be exceeding difficult, unless I could certainly know how much of the Airs pressure is taken off by the smalness of such and such a Pipe, and whether it may be wholly taken off, that is, whether there can be a hole or pore so small, into which Air could not at all enter, though water might with its whole force, for were there such, ’tis manifest, that the water might rise in it to some five or six and thirty English Foot high.

I know not whether the capillary Pipes in the bodies of small Trees, which we call their _Microscopical pores_, may not be such; and whether the congruity of the sides of the Pore may not yet draw the juyce even higher then the Air was able by its bare pressure to raise it: For, Congruity is a principle that not only unites and holds a body joyned to it, but, which is more, attracts and draws a body that is very near it, and holds it above its usual height.

And this is obvious even in a drop of water suspended under any Similar or Congruous body: For, besides the ambient pressure that helps to keep it sustein’d, there is the Congruity of the bodies that are contiguous.

This is yet more evident in Tenacious and Glutinous bodies; such as Gummous Liquors, Syrups, Pitch, and Rosin melted, &c. Tar, Turpentine, Balsom, Birdlime, &c. for there it is evident, that the Parts of the tenacious body, as I may so call it, do stick and adhere so closely together, that though drawn out into long and very slender Cylinders, yet they will not easily relinquish one another; and this, though the bodies be _aliquatenus_ fluid, and in motion by one another, which, to such as consider a fluid body only as its parts are in a confused irregular motion, without taking in also the congruity of the parts one among another, and incongruity to some other bodies, does appear not a little strange.

So that besides the incongruity of the ambient fluid to it, we are to consider also the congruity of the parts of the contein’d fluid one with another.

And this Congruity (that I may here a little further explain it) is both a Tenacious and an Attractive power; for the Congruity, in the Vibrative motions, may be the cause of all kind of attraction, not only Electrical, but Magnetical also, and therefore it may be also of Tenacity and Glutinousness.

For, from a perfect congruity of the motions of two distant bodies, the intermediate fluid particles are separated and droven away from between them, and thereby those congruous bodies are, by the incompassing mediums, compell’d and forced neerer together; wherefore that attractiveness must needs be stronger, when, by an immediate contact, they are forc’d to be exactly the same: As I shew more at large in my _Theory_ of the _Magnet_.

And this hints to me the reason of the suspension of the _Mercury_ many inches, nay many feet, above the usual station of 30 inches.

For the parts of _Quick-Silver_, being so very similar and congruous to each other, if once united, will not easily suffer a divulsion: And the parts of water, that were any wayes _heterogeneous_, being by _exantlation_ or rarefaction exhausted, the remaining parts being also very similar, will not easily part neither.

And the parts of the Glass being solid, are more difficultly disjoyn’d; and the water, being somewhat similar to both, is, as it were, a medium to unite both the _Glass_ and the _Mercury_ together.

So that all three being united, and not very dissimilar, by means of this contact, if care be taken that the Tube in erecting be not shogged, the _Quicksilver_ will remain suspended, notwithstanding its contrary indeavour of Gravity, a great height above its ordinary Station; but if this immediate Contact be removed, either by a meer separation of them one from another by the force of a shog, whereby the other becomes imbodied between them, and licks up from the surface some agil parts, and so hurling them makes them air, or else by some small heterogeneous agil part of the Water, or Air, or Quicksilver, which appears like a bubble, and by its jumbling to and fro there is made way for the _heterogeneous Æther_ to obtrude it self between the Glass and either of the other Fluids, the Gravity of _Mercury precipitates_ it downward with very great violence; and if the Vessel that holds the restagnating _Mercury_ be convenient, the _Mercury_ will for a time _vibrate_ to and fro with very large _reciprocations_, and at last will remain kept up by the pressure of the external Air at the height of neer thirty inches.

And whereas it may be objected, that it cannot be, that the meer imbodying of the _Æther_ between these bodies can be the cause, since the _Æther_ having a free passage alwayes, both through the Pores of the Glass, and through those of the Fluids, there is no reason why it should not make a separation at all times whilst it remains suspended, as when it is violently disjoyned by a shog.

To this I answer, That though the _Æther_ passes between the Particles, that is, through the Pores of bodies, so as that any chasm or separation being made, it has infinite passages to admit its entry into it, yet such is the tenacity or attractive virtue of Congruity, that till it be overcome by the meer strength of Gravity, or by a shog assisting that Conatus of Gravity, or by an agil Particle, that is like a leaver agitated by the _Æther_; and thereby the parts of the congruous substances are separated so far asunder, that the strength of congruity is so far weakened, as not to be able to reunite them, the parts to be taken hold of being removed out of the attractive Sphere, as I may so speak, of the congruity; such, I say, is the tenacity of congruity, that it retains and holds the almost contiguous Particles of the Fluid, and suffers them not to be separated, till by meer force that attractive or retentive faculty be overcome: But the separation being once made beyond the Sphere of the attractive activity of congruity, that virtue becomes of no effect at all, but the _Mercury_ freely falls downwards till it meet with a resistance from the pressure of the _ambient_ Air, able to resist its gravity, and keep it forced up in the Pipe to the height of about thirty inches.

Thus have I gently raised a Steel _pendulum_ by a Loadstone to a great Angle, till by the shaking of my hand I have chanced to make a separation between them, which is no sooner made, but as if the Loadstone had retained no attractive virtue, the _Pendulum_ moves freely from it towards the other side.

So vast a difference is there between the attractive virtue of the _Magnet_ when it acts upon a contiguous and upon a disjoyned body: and much more must there be between the attractive virtues of congruity upon a contiguous and disjoyned body; and in truth the attractive virtue is so little upon a body disjoyned, that though I have with a _Microscope_ observed very diligently, whether there were any extraordinary _protuberance_ on the side of a drop of water that was exceeding neer to the end of a green stick, but did not touch it, I could not perceive the least; though I found, that as soon as ever it toucht it the whole drop would presently unite it self with it; so that it seems an absolute contact is requisite to the exercising of the tenacious faculty of congruity.