_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.
* * * * *