231
When I made the foregoing Observations, I
designed to repeat most of them with more care &
exactness, & to make some new ones for determining
the manner how the rays of light are bent in their
passage by bodies, for making the fringes of colours wthwith
the dark lines between them. But I was then interrupted,
& cannot now think of taking these things into further
consideration. And since I have not finished this part of
my designe, I shall conclude, with proposing only some
Quæres in order to a further search to be made by others.
Quære 1. Do not Bodies act upon light at a dis
tance & by their action bend its rays & is not this action
(cæteris paribus) strongest at the least distance?
Qu. 2. Do not the rays wchwhich differ in refrangibility
differ also in flexibility & are they not by their different
inflexions separated from one another so as after separation
to make the colours in the three fringes [above described? And
after what manner are they inflected to make those fringes?
Qu. 3. Are not the rays of Light in passing
by the edges & sides of bodies bent ned several times
backwards & forwards with a motion like that of an
Eele? And do not the three fringes of coloured light above mentioned arise from three such bendings?
Qu. 4. Do not the rays of Light chwhich fall upon
bodies & are reflected or refracted, begin to bend before
they arrive at the bodies; & are they not reflected
refracted & inflected by one & the same Principle
acting variously in various circumstances?
Qu. 5. Do not bBodies & Light act mutually
upon one another, that is to say, Bodies upon Light in
emitting, reflecting, & refracting & inflecting it, and Light
upon bodies for heating them & putting their parts into a vibrating232 vibrating motion wherein heat consists?
Qu. 6. Do not black bodies conceive heat more
easily from light then those of other colours do, by
reason that the light falling on them is not reflected
outwards but enters the bodies & is often reflected &
refracted within them untill it be stifled & lost?
Qu. 7. Is not the strength & vigor of the action
between Light & sulphureous Bodies observed above,
one reason why sulphureous bodies take fire more
readily & burn more vehemently then other Bodies do?
Qu. 8. Do not all fixt bodies when heated
beyond a certain degree, emit light & shine, & is not this emission performed by the vibrating
motions of their parts?
[Qu. 9. Is not fire a body heated so hot as to
emit Light copiously? For what else is a red hot
Iron then fire, & what else is a burning coale then
red hot wood?
Qu. 10. Is not flame a vapour, fume or
exhalation heated red hot, that is so hot as to shine?
For Bodies do not flame without emitting a copious
fume, & this fume burns in the flame. ✝ The Ignis fatuus – ✝ The Ignis fatuus is a vapour shining without heat, & is there not the same
difference between this vapour & flame as between rotten wood shining
without heat & burning coales of fire? In destilling hot spirits if yethe
head of the still be taken off the vapour wchwhich ascends out of the still will
take fire at the flame of a candle & turn into flame & the flame
will run along yethe candle from vapor from the candle to the Still. Some Bodies heated by motion or fermen
tation if the heat grow intense fume copiously, & if the heat be great
enough the fume will shine & become flame. Metals in fusion do not flame for
want of a copious fume except Spelter wchwhich fumes copiously & thereby
flames. All flaming bodies as oyle, tallow, wax, wood, fossil coales, pitch,
sulphur, by flaming wast & vanish into burning smochwhich smoke if
the flame be put out is very thick & visible & sometimes smells strongly
but in the flame loses its smell by burning, & according to yethe nature
of the smoke the flame is of several colours, as that of sulphur blue,
that of Copper opened with A Sublimate green, that of tallow yellow.
Smoke passing through flame cannot but grow red hot & red hot smoke
can have no other appearance then that of flame.
Qu. 11. Do not great bodies conserve their heat the longest their parts heating one another, & May not great dense & fixt bodies when heated beyond
a certain degree emit light so copiously as by the emission
& reaction of its light & the reflexions & refractions of it's
rays within its pores to grow still hotter till it comes to a
certain period of heat, such as is such as is l that of the Sun. And
are not the Sun & Fixt Stars great Earths vhementlyvehemently hot,
whose heat — — — Qu. 11. Are not the Sun & fixt Stars great
Earths vehemently hot, whose heat is conserved by
the greatness of the bodies and the mutual action & reaction between them & the Light
wchwhich they emit, & whose parts are kept from fuming
away not only by their fixity but also by the vast
weight & density of the Atmospheres incumbent upon them
& very strongly compressing them & condensing the vapours & exhalations wchwhich arise from them.
Qu. 12. Do not the rays of light in falling
upon the bottom of the eye exctite vibrations in the
Tunica Retina? wchwhich vibrations being propagated along
the solid fibres of the Optic nerves into the Brain
cause the sense of seeing? For because dense bodies
conserve their heat a long time & the densest bodies
conserve their heat the longest, the vibrations of their
parts are of a lasting nature & therefore may be
propagated along the solid fibres of uniform dense
matter to a great distance for conveying into the
brain the impressions made upon all the Organs of
sense. For that motion wchwhich can continue long in one
& the same part of a body can be propagated a long way233 way from one part to another, supposing the Body homo
geneal so that the motion may not be reflected, refracted
interrupted or disordered by any uneavenness of yethe body.
[Qu. 13. Do not several sorts of rays make
vibrations of several bignesses wchwhich according to their
bignesses excite sensations of several colours much
after the manner that the vibrations of the air
according to their several bignesses excite sensations
of several sounds? And particularly do not the most
refrangible rays excite the shortest vibrations for
making a sensation of deep violet, the least refran
gible the largest for making a sensation of deep
red, & the several intermediate sorts of rays, vibrati
ons of several intermeditate bignesses to make vibra sensa
tions of the several intermediate colours?
Qu. 14. May not the harmony & discord of
colours arise from the proportions of the vibrations
propagated through the fibres of the Optick nerves into
the brain, as the harmony & discord of sounds arises
from the proportions of the vibrations of yethe Air. For
some colours are agreable as those of gGold & Indigo,
& others disagree.
Qu. 15. Are not the species of oObjects seen with
both eyes united where the Optick nerves meet before
they come into the brain, the fibres on the right side
of both Nerves uniting there & after union going
thence into the brain in the Nerve which is on the
right side of the head & the fibres on the left side
of both Nerves uniting in the same place & after
union going into the brain in the Nerve wchwhich is on the
left side of the head & these two Nerves meeting in
the brain in such a manner that their fibres make
but one entire species or picture, half of wchwhich on yethe
right side of the sensorium comes from the right side
of both eyes through the right side of [both Optick
Nerves to the place where the Nerves meet & from
thence on the right side of the head into the brain, &
the other half on the left side of the sensorium comes
in like manner from the left side of both eyes. For
the Optick Nerves of such animals as look the same
way with both eyes (as of Men, Dogs, Sheep, Oxen &c.)
meet234
Qu.16. Are not Is not the free passage of l light through pellucid bodies an argument that all all pell bodies are very porous. for giving passage to yethe rays
of light? that Water is nineteen times lighter in specie then Gold & therefore
would be since the gravity of since the matter in bodies is proportional to their gravity
water would have eighteen times more pores then parts of gold were sol perfectly solid or void of all
pores. But gold is also very porous as appears by the soaking of quicksilver into it &
& by the squeezing of water through it & principally by the passage of light through its particles when dissolved foliated or dissolved in Aqua
regia. Were the pores of gold but equal to its parts the pores of rain water
would be contain 37 time mos more spacesound ratio
nal Hypothesis for explaining how water can be so porous & yet be uncapable
of compression by force, may by doubtless by the same Hypothesis explain how gold may have
3 above 37 time be as porous as he pleases & all other bodies as much more
porous then gold as they are lighter in specie. Suppose a body be were composed of
parts lying together with as much pores between them, & that these parts are were
composed of smaller parts lying tohgether with as much pores between them & that these parts be were
composed of parts still smaller with as much pores between them & so on for as
many compositions as you please
And if in this progression there be were ten compositions, will would have 1023
above a thousand times more pores then parts; if twenty compositions, it willould have above a thousand thousand
times more pores then parts; if thirty compositions, it will would have above a thousand
thousand thousand thousand times more pores then parts & so on perpetually. Certainly
the passa But whatever be the texture of bodies, they must be so porous as in all positions to give
passage to yethe rays of light in right lines through their pores. For whatever the rays of light be
whether its rays they consist in the vibrations of a medium, or be bodies trajected, if
in passing through the pores of pellucid bodies they do not find room enough to go on
in right lines they must be turned whenever they are once turned disturbed &
turned out of their direct courses, they will go on in their new courses till
they are disturbed again, & they more they are disturbed the more they
will err & never return no more to their first courses unless by very great
accident. To suppose that light as of often as yethe rays of light are
turned out of their way by some parts of yethe bodies, they will be turned
into way again by others is as precarious & extravagant as to suppose
that sound can pass through a forest of trees without they the suns light can pass can pass through
a heap of sand & after many reflexions emerge in the same right lines as often in wchwhich they it came
from yethe sun, some the sands being so disposed that some ethe
rays into their right course as often as others turn them out of their way. The
great porousness & admirable structure of bodies is further argued from the lastingness of the vibrating
motions of their parts wherein heat consists, & from the great capacity of
one & the same matter by corruption & generation to put off & put on all
manner of forms. For as the For whilst For without great porousness the parts of bodies could no
more vibrate then a stone spring can tremble in the middst of a heap of sand. It is
further argu And it may be further argued from the great capacity of one
& the same matter by corruption & generation to put off & put on all
manner of forms, For & be changed into all sorts of shapes. C The contrivance
of the bodies of living creatures is admirable. Not a member but has its use
& is mighty well fitted for that use. And since the forms & uses of matter are infinite can we beleive that he who
contrived yethe bodies of animals wthwith so much artifice
& curious in the contrivance of matter contriving the its the texture of matter so as to
fit it make it capable by corruption of all manner of forms & uses uses applicab of matter for those ends for
which it is fitted. For the forms & uses of matter are infinite innumerable & therefore we we are not to consider it as partic irregular particles irregu
larly casually laid together like stones in a heap, but as formed wisely for
all those uses. One use of matter is that to admit menstruums easily into its pores
for in order to new mixtures by & actions by fermentation putrefaction corruption & generation, another to conceive heat easily
& keep it long for promoting changes by corruption fermentation putrefaction & generation, a those
to transmit light for refract & reflect light for producing all the
phænomena of colours. A fourth of bodies wthwithout wchwhich where in the beauty
of nature mightily chiefly consists. Without these uses matter the earth would have been
a dead lump void of without void of heat & motion & generation & alteration & variety of
colours: & therefore it is reasonable to allow that he who contrived
all things with wisdome, framed matter in such a manner as to fit it best for these
uses, & by consequence made it very porous.
Qu. 17 Is there not something indiffused through all space in &
through wchwhich bodies move without resistance & by means of wchwhich they
act upon one another at a distance in harmonical proposrtions of their
distances.
Qu. 8. — — — And do not all bodies wchwhich abound wthwith sulphureous parts when those
or terrestrial parts emit light whenever those parts are sufficiently agitated by putrefaction heat putrefaction attrition percussion putrefaction or any other
cause emit light? 1 So the waves of yethe salt water of the sea in a storm by dashing against one
another emit light, 5 the shavings of steel being struck scraped of by a stroke wthwith a flint melt by the grow hot & melt by the action & shine
like sparks of fire by the action. 3 The back of a cCat being struck obliquely with
ones hand emits a faint light in a dark room. 6 Iron may be hammered till it grows red hot 7 The wheel of a cart or chariot by
vehement attrition sometimes heats the axes so to great a grea degree as to set it on flame
7 Moist stacks of hay or corn by fermentation & putrefaction grow hot till they emit a shining flame. 2 Quicksilver by any vehement agitation in vacuo shines with a faint light th & so does
rotting wood & rotting flesh or fish tho all the parts of the body be not agitatted so vehe
mently as to make the body sensibly warm. But wthwithout motion no bodies emit light
And so do the putrid vapours called Ignes fatui 4 One sort of Phosphorus by being placed some time in the Suns light conceives an
an agitation by wchwhich it shines for some after in the dark: another sort by the access
of fresh air is easily put into motion emits a copious fume wthwith a sulphureous smell &
shines & by rubbing it quietly grows hot & takes flame.
But without motion no bodies emit light Some liquors by mixing with one another grow hot & some grow so hot as to emit a shining
vapour or flame.
sed quo ipsœ nos latent, et ex hoc nomine quaetatibus specificis causes Phænomenon imposit nondum
patentibus imposito deterremar ab a causis hisce indagandis, quasi quidem illæ
penitus essent deploratæ postquam magnus ipse Philosophus Aristoteles in eas
penetrare non potuerat. Gravitas igitu sic Hoc sensu gravitas dicend est erit qualitas manifesto,
et causa sola gravitatis causa de qua Newtonus nihil statuit, occulta dicenda dicenda esterit donec
manifesta addatum dicindo potest occulta. Occultam tamen esse in sensu Scholasticorūum,
ita scilicet ut manifestari non poterit, Newtonus minima statuit.
nitius ludit in verbis et Newtonum calumnia adoritur. Ludit etiam in verbis ub Deum
vocat qui non est Dominus Universorum, et animam vocat quo corpus non animatur.
conjungi quiant ut cohærescunt. p. 340. lin. 27.
Quæst.24. May not the forces by wchwhich the small particles of
bodies cohere & act upon one another at small distances for producing the above mentioned phænomena
of nature, be electric? For altho electric bodies do not act at a sensible
distance unless their virtue be excited by friction, yet that vertue may
not be generated by friction but only expanded. For the particles of all
bodies may abound with an electric spirit wchwhich reaches not to any sensible
distance from the particles unless agitated by friction & exp or by some other
cause & expan rearefied by the agitation. And the friction may not rarefy
the spirit not of all the particles in the electric body but only of those only wchwhich are on the
outside of it: so that the action of the particles of the body upon one another for cohering & pro
ducing the above mentioned phænomena may be vastly greater then
that of the whole electric body to attract at a sensible distance by
friction. And if there be such an lnly it must very much
influence the actions & motions & actions of the small parts particles of the bodies
upon amongst one another. so that without considering it, philosophers will never be able to
give an account of the above mentioned phænomena the phænomena arising from those motions & actions.
And Quæst 25. Do not all bodies therefore aboun so far as these phæno
mena may be performed expl performed by the spirit wchwhich causes electric attraction
it is unphilosophical to look for any other cause.
Quæst 25 Do not all bodies therefore abound wthwith an electric
a very subtile active spirit potent elastic spirit by wchwhich light is emitted refrac
tec & reflected, electric attractions & fugations are performed, & the
small particles of bodies cohere when contiguous, & agitate one another
at small distances & regulate almost all their motions amongst them
selves. For electric – – – – uniting the thinking soul & unthinking body.
This spirit may be also of great use in vegetation, wherein three things
are to be considered, generation, nutrition & præparation of nourishment.
Generation is nothing else then separating a branch from the tree &
giving it better nourishment. If a separated branch takes root in the earth
& or a separated twigg or bud by grafting or inoculation ethe root
of a young stock, it grows into a new tree as big a the ftroee from wchwhich it was separa
ted being better nourished from a young root then from an old one. The seed of
a tree while it grows upon the tree has the nature of a branch or twig or
bud, where it while it grows upon yethe tree it has the nature of is a part of
it like a bud the tree: but if separated & set in the earth to be better nou
rished, the embryo or young tree conteined in it takes root & grows into a new tree. like manner The egg
of a female wthwith the embryo formed in it while it grows in the ovarium seed is a part branch of yethe mothers body
but the Embryo formed in it & partakes of her life, growing great being separated from the
mother & growing great by due nourishment as a branch or twigg or budd or seed
of a tree is of being separated from the tree & growing into a new tree. For by the act of
generation nothing more is done then to ferment the sperm of the female by yethe
sperm of yethe male that it may thereby become fit nourishment for yethe Embryo. For yethe
nourishment of all animals is prepared by fermentation & the ferment is taken from animals of the same kind , being & makes the nourishment subtile & spiritual. thereby In adult animals the
nourishmtment is fermented by the choler & pancreatic juice, & much more ought yethe
nourishemtment of an Embryo to be prepared by fermentation & this for yet both wchwhich come from the blood. The Embryo not being able to
ferment its own nourishment chwhich comes from the mothers blood has it fermented by the sperm wchwhich comes from yethe fathers
blood, & by this nourishment bec it swells, drops off from & Ovarium & begins to grow
with a life distinct from that of yethe mother. And in Oviparous creatures if the
sperm of the female an ingredient of the egg fermented with the sperm of the fmale the white & yethe yelkyolk of the egg will
not be fit nourishment for the Embryo. [So then generation is nothing else then the
the Embryo grows upon the body of the mother before generation as a twig grows
upon a tree & all generation is nothing else than the preparation of due nourishments
for the Embryo to grow with a distinct life distinct life when separated. from th]
Now in all fermentation wchwhich generates spirits, the ferment abounds wthwith a sup
prest acid wchwhich being more attracted by the other body forsakes its own to to rush upon & dissolve yethe other & by the violence of the actions breaks both its
own particles & the particles of yethe other body into smaller particles & these by their
subtilty volatility & continual digestion ethe whole mass into into as subtile
parts as they it can be resolved by putrefaction. [And by this means bodies must lose their
old form & texture before they & be destroyed & broken to pieces into the last parts before they
can be formed.] For as an old house must be pulled
before they can be put together in another manner a new house can be
be built out of their its materials: So natural bodies must be dissolved broken & separated into
they
can be formed anew a new natural body can be formed out of them.
And when the nutriment nourishment is thus prepared by dissolution & subtiliation, the particles are of
the body to be nourished draw to themselves out of the nourishment the particles of the
same density & nature wthwith themselves. For bodies particles of one & the same nature
draw one another more strongly then particles of different natures do. And when And therefore in the bowels of the earth
many particles of the same kind are drawn together out of yethe nourishment they
will be apt to coalesce in such figure textures as the particles wchwhich drew them
did before because they are of the same nature because as we see in the particles of salts
wchwhich if they be of the same figure kind always crystallize in the same figures.
And b for faciliating this assimilation of yethe nourishment & presering the nourished
bodies from corruption it may be presumed that as electric attraction is excited
by friction so the electric atr it is excited invigotedrated also by the vegetable life life so it may
be invigorated also by some other causes & particularly by some agitation caused in the electric spirit by the vegetable life of the
particles of living substances: & the ceasing of this vigour upon death may be the reason why yethe death of Animals is
accompanied wthwith putrefaction.
But these things I only hint as Quæres without asserting any thing. I under the heads of Quæres
These things I have proposed under the heads of Quæres & leave them to be
examined.
by such a fermentation as generates spirits convenient spirits.
For all the use wchwhich nature makes of such fermentations & putrefactions as generate spirits
& & tends to pe & are the beginning of putrefaction seems to be for destroying the texture texture & forms & breaking the texture of
of the particles of bodies of bodies & breaking their particles into less parti
cles whereby they may become subtile & spiritual & fit nourishment for
things wchwhich grow. For fermentation & putrectionputrefaction destroys & subtilizes & reduces all things
to their least parts particles & nutrition recomposes those particles & sets them together
in such an order as to be like to make them become of the same nature wthwith
the things nourished.]
236
De Motu et Sensatione Animalium.
1 Attractionem electricam per spiritum quendam fieri qui corporibus
universis inest, et aquam vitrum Crystallum aliaque corpora solida libere permeat libere pervadit. Nam corpora electrica post fortiter
attritioanem aurum foliatum per interpositam aquæ vel vitri substantiam trahunt.
3 Capillamenta pellucid utiqꝫque solida uniformia et pellucida a cerebro per omnes sensuum
nervos ad organa sensuum produci et spiritum electricum in his capillamentis
latentem esse medium per elasticum et cujus vibratioeibus per totam capillamentorum
longitudinem propagatis s in sensorium quam celerrime propagatis sensa
tionenem peragaitur.
4 Et Capillamenta alia solida uniformia et pellucida a cerebro per medullam spinalem
in ad musculos propagari pergere. Et spiritu spiretus electrici in his nervis latentis vibrationes a cerebro per spiritum electrici
in his capisa latentem in musculos propagari quibus musculi agitati contraha contrahantur
ad membra movenda. His utiqꝫque vibrationibus vim electricam in cuticulis musculorum
intendi, & per vim ullam auctam cuticulas aliquantulum contrahi & & contractione sua musculos simul contrahere.
Nam spatium solidum quod musculus occupat diminuitur per contractionēem
musculi
2 Spiritum hunc electricum esse medium quo sensatio obje dilatari et contrahi et propterea elasticum esse & eundemqꝫque in nervis animalium latentem
esse medium quo objecta sentimus et ictu oculi corpora membra movemus. [Nam Spiritus quos vocant anima
les nervis corporei nervis corporei sunt et e nervis in musculos tam cito propagari neque
unt ob densitatem tardieus moventur.] & vibrationes per eundem quam celerrime
propagari.
4 Et capillamenta alia solida uniformia & pellucida a cerebro per medullāam
spinalem in musculos propagari produci; ac per quae vibrationes & Spiritusum autem electriciorum [in his nervis capillamentis latentisūum vibrationes]
a cerebro per capillamenta in musculos propagari ad membra movenda substan
tiam musculorum agitandam et membra movenda. Liquores enim sicagitati expan
di debent perinde ac si per calorem agitarentur, & musculi per expansionem suam
musculos contrahent liquorum suorum contrahentur, & membra movebunt.
4 Et capillamenta alia solida uniformia & pellucida a cerebro per
medullam spinalem et ejus ramos in musculos pergere per quæ vibrationes
spirituum electricorum a cerebro propagentur ad substantiam musculorum
agitandam & membra movenda. Liquores enim per has vibrationes agitati
expandi debent perinde ac si per calorem agitarentur.
Vibrationes in spiritu elastico per radios lucis
Spiritum electium lucere & reflectere refrangere & per lucem agitari
237
De vita & morte vegetable.
1 Corpora omnia vim habent electricam & particulas eorum electricas ad parvas
tantum agere distantias agere nisi vis eorum vim illam in superficiebus particularum
fortissimam esse sed ad parvas tantum distantias non longe
actione cieatur.
3 Particulas corporum per vim electricam diversimonde coalescere & fortissime arte cohæ
rere. Et particulas minores fortius agere & artius cohærere.
Particulas menstrui quæ maxima vi attr electrica linguam particulas linguæ
fortissime agitant sensationem acidi ciere.
Menstruum corp acidum corpora densa dissolvere per particulas suas acidas, vi sua
attractrice in pa intersticia partium ultimæ compositionis irruentes & partem unam
quamqꝫque circumeuntes & circumdantes ut cortex nucleum vel atmosphæra terram.
et partems vero acido circumdatas corpus suum linquere et in Menstruo fluitare, atqꝫque
acido suo ambiente linguam pungere excitando sensationem salis. Nam acidum a parte nucleo inclusao
attractum & retentum in partes agita minus fo & impeditum minus agitat in linguam quam prius.
Acidum salis ab externo corpore magis attractum quam a nucleo proprio, in
externum illud ruit & nucleus acido nudatus pondere suo decidit & in fundum præcipitatur.
His dissolutionibus particulas corporum acidas vehementer agitari et agitari et earum vim electricāam per agitationem
suam et frictionem, vis earum vim electricam intendi agere propagari quam prius & dissolutionem promovere.. Nam vis electrica per
frictionem & cieri solet.
Particulas acidas partibus corporum dissolutis dissolutis cor dissovendis corporum partibus compositionis ultimæ longe minores
esse ut in earum insterstitia ingredi irruere possint et sed non adeo parvas tamen ut poros
harum partium pervadant permeent. Ideoqꝫque partes immutatæ manent acidoqꝫque suo ambiente nudatæ ut supra & præ
cipitatæ, si sint metallici generis ut fundi possint per fusionem in corpus antiquum redeunt. Mercuri
us itidem cum metallis amalgamando commixtum interstitia partium compositionis
ultimæ ingreditur, poros autem harum partium ingredi non potest idioqꝫque per destillationemē
abstractus relinquit partes immutatas, & hæ partes per fusionem in corpus antiquum
pristinum revertuntur.
Si dissolutio ejusmodi est ut per actionem Menstrui et reactionem corporis spiritus
aliqui subtiliores excitentur qui poros particularum & compositionis ultimæ pervadere possint
ingredi possint, tunc spiritus illi paulatim permeant & dissolvunt has partes perinde u et in particulas
compositionis penultimæ separant, perinde ut Menstruum acidum dissolvebat corpus
totum et in partes compositionis p ultimæ, in casu priore separabat. Et corpus for
mam veterem jam amisit. Nam particulæ compositionis penultimæ in partes compo
sitionis ultimæ non nisi per generationemm redeunt. Et par est ratio dissolutionis
particularum compositionis penultimæ in particulas compositionis ante penultimæ &c.
Hasce vero dissolutiones p corruptionem corporis et putrefactionem dicere solemus.
Fermentum est substantia quæ spiritibus sub
Putrefactio per fermentum quandaqꝫque inducitur, et fermentum est corpus vegeta
bile spiritibus abundans quibus esiumū corporis corporis fermentandi putrefaciendi ingredi compositionis ultimæ permeare possunt
et dissolvere & partes
quibus dissolutio putrefactio compleatur. Nutrimentum animalium per succos in stomacho et maxime per
bilem fermentatur.
Dissolutio corporis in partes compositionis ultimæ violentior est, & cito perfici
tur & cessat. Ea partium illarum in partemesibus compositionis penultimæ lente fit diuturnior est & modico
peragitur calore qui spiritus subtiliores dissolventes non abigat sed actionem eorum juvet.
Corpus per putrefactionem fractum comminutum & in partes minimas
redactum, formam veterem amisit & formarum innumerabilium novarum
per generationem est capax. Nam corruptio putrefactio corpus comminuit generatio partes
minimas
naturam corporis vivi cui substantia fermentata et corr putrefacta in nutrimen
præbetur. Ut cum vegetabilia innumera eodem fimo, innumera animalia innumera
eodem cibo per bilem fermentato nutriuntur.
Ut frictione corporis electrici intenditur ejus attractio sic etiam etiam Actione vivendi intenditur vis electrica partium viventis, qua & forti attractione fit ut partes
illæ et situm formam propriuam & situm inter se conservent & nutrimento suo paulatim communicent perinde237 perinde ut Manges convertit ferrum in magnetem & ignis convertit corpora in
ignem & fermentum convertit pastam in fermentum: at cessante vita vegetabili cessat attractio
illa vegetabilis vitalis et ejus defectu simul incipit actio moriendi quam corruptionem & putrefactionem dicimus.
In generatione animalium per misturam et fermentationem seminum
cietur et accenditur attractio vegetabilis attractio vegetabilis cietur & quasi flamma vitalis accenditur qua languescente animal debilitatur
& ægrotat & cessante moritur & putrescit: et contra. Ovum in ovario matris
ante generationem vivit quidem tantum ut pars corporis materni: post at per fermentationem seminum
vitam propriam vegietabilem acquirit ut animal a matre diversum, & vita propria per hanc vitam statim incipit
vegetare ac crescere & nutrimentum in se convertere. [Fermentatio autem per attractionem
uti diximus perficitur et motu excitato suo attractionem illam intendit & fortiorem reddit]. Per fermentum
corpo itaque corpora mortua dissolvuntur, viva nutriuntur & crescunt. Mortua propter
debilem partium attractionem non dissolvuntur sed menstruum vincunt. De motu
2 Corpora vi electrica quandoqꝫque plerumqꝫque trahi quadoqꝫque vero dispelli per experimenta
constat; et particulas aeris & vaporum sese dispellere. Particulas etiam aqua olei dispellere
particulas aquæ.
Si posset Menstruum alios illos pervadere, vel si auri partes
primæ et secundæ compositionis possent separari, fieret aurum
vel fluidum vel saltem magis malleabile. Si aurum fermentesce
re posset [et [per putrefactionem in particulas minimas resolvi,
idem ad instar substantiarum vegetabilium & animalium putres
centium, formam suam amitteret, in fimum pristinum abiret vegetabi
libus nutriendis aptum & idem aliud fortum per digestionem in fimum mollem resolvi vegetabilibus nutriendis aptum, idem & per generationem] in aliud
quodvis corpus transformari posset. [Et similis et ratio Gem
marum & mineralium corp ossium & omnium corporum durorum Eadem intellige de Gemmis mineralibus lapi ossibus & aliis corporibus duris & eorum partibus compisitionis primæ secundæ tertiæ &c ultimæ.
Visciditas est imperfecta fluiditas cum attractione partium.
Fluiditas autem Fluiditas sita est in partium parvitate qua facile commo
veantur et lubricitate qua facile labantur inter se. Intellige
partes ultimæ compositionis. Visciditas est imperfecta fluiditas cum
attractione partium cohæsione partium cum per attractionem partium. Hujus visciditatis acidum sæpe causa est,
sæ spiritus alius lubricus terræ junctus: ut cum Oleum Tere
binthinæ capiti suo mortuo redditum fit tenax.
Charta oleo inuncta transitum oleo quidem, non autem aquæ, concedit,
propterea quod aqua oleo non miscetur sed fugatur ab eo.
Acidum primigenium videtur2 constare1 particulis compositis figuram
sphæricam per summam attractionem induentibus [perinde ut Terra per gravitatem sphærica fit]; et particulæ hae
sunt majores aquæ & minores terræ partibus, seu inter eas
mediæ, et utrarumqꝫque attractrices.
Cum acidæ Menstrui particulæ corpus aliquod dissolvunt, hæ
ob parvitatem poros corporis majores ingrediuntur & singulas ejus particulas in
ternas compositionis ultimæ, seipsis utiqꝫque longe majores, circumeunt & includunt undiqꝫque
[ut cortex nucleum vel mare terram et includendo separant a
corpore. [Unaquæqꝫque vero corporis particula mediante acido attracto
et circumposito in Menstro deinceps fluitat & linguam pungit, hoc
est in particulam salis convertitur. Deinde actione et reactione lenta
et continua inter particulam corporis et acidum ambiens per fer
mentationem naturalem excitata, acidum spiritus subtilus generantem excitata spiritus illi poros particulæ pau
latim ingrediuntur, texturam ejus lente dissolviunt & cum ea tandem
miscentur per minima: quam operationem putrefactionem dicimus.
Corpus jam maxime comminutum et cum particulis acidis in
separabiliter commixtum formam veterem amisit & forma
rum innumerabilium novarum factum est capax, siquidem
particulæ compositi per generationem iterum congregari, coa
lescere et in ordinem redigi possint, idqꝫque diversimode pro
natura corporum vivorum quibus nutrimentum præbeant.]
Viva enim per fortem attractionem & magnitudinem particularum formam seu texturam suam et ser
vant et nutrimento suo paulatim communicant: at cessante
vita cessat attractio illa vitalis et incipit actio moriendi quam
corruptionem et putrefactionem dicimus.] Nam quemadmodum
vis electrica per frictionem cietur & vis magnetis in ferrum
transfertur et vis urendi in corpora ignem nutrientia propa
gatur: sic vis quædam attractiva per fermentationem naturalem
cieri videtur, in qua vita vegetabilis consistit, quæqꝫque ideo attractio
vitalis dici mereatur, et hæc vis ab actione vivendi conservari
videtur et a corpore vivente in corpore fermentato cieri videtur et in corporibus vivis per actionem vegetandi conservari & in nutrimentum paulatim transferri, potest
et cessante vita cessare.] Et hæc vis electrici videtur esse generis
propterea quod per motum et attritionem particularum corporis vege
tantis cieatur. Corpora utiqꝫque omnia quantum sentio vi electrica
pollent, et particulæ electricæ ad minimas distantias semper agere
possunt fortissime et per actiones illas diversimode coalescere et
cohærere; et actiones illæ electricæ in fermentatione et vegetatione per238 per motum et frictionem particularum intendi possunt et longius
propagari, et cessante motu remitti.
Si aurum ferementescere posset [corrup & per corruptionem in vfimum verti vegetabilius
nutriendis aptum, idem per o
Nam quemadmodum domus antiqua dirui debet et in lapides singulos separari debet priusquam ex ejus materia domus nova construatur
deinde ex lapidibus novo ordine compositis domus innumeri nova formæ cujuscunqꝫque componi possit: sic fit in resolutione & compositione corporum
naturalium. Corpus antiquum per putrefactionem dirui debet et in particulas minimas ex quibus generatum fuit resolvi priusquam ex ejus
materia corpus novum generari potest, [deinde ex materia putrefacta corpora nova diversarum formarum generari posunt] Generatio autem illa
Et ubi particulæ illæ subtilissimæ diversarum magnitud densitatum magnitudinum & virtutum per fermentationem & putrefactionem separantur & inter se confuse mis
centur, & menstruum dissolvens & corrumpens aciditatem suam agendo amissit;tum apta est materia illa per fermentationem & putrefactionem
attenuata ad nutriendum corpus vivum ejusdem generis cum corpore ex quo fermentum desumptum fit fuit.
239
Various Conjectures.
Flame is fume & differs from
Flame is red hot fume & differs from fume wchwhich is not red hot as red hot iron
differs from iron wchwhich is not red hot.
Heat is the consists in yethe trembling agitation of the smallest parts of bodies all manner of ways; no body being
& the parts of all bodies are always in some agitation.
The globe of the Earth is perpetually increased by the sediment of water
Earth is the condensed sediment of water & water is fluid earth.
Burning spirits are oyles united wthwith phlegm by fermentation.
Tincture of Cochinell extracted wthwith spirit of wine being powered in small quantity
into a great mass of water, tinges the whole water because the particles of the
Cochinell are more attracted by the water then by one another, & therefore recede
from one another.
Water has but a small power of attracting because it has but a small
quantity of acid in its composition. For we call that an acid wchwhich attracts & is
attracted strongly. Whence it is that those things wchwhich dissolved in water are
dissolved slowly & without effervescence. But where there is a strong the attraction is
strong & the particles of the menstruum are every where on all sided attracted by the
particles of the metal or rather the a particles of the metall are is on all sides
attracted by the particles of the menstruum, these agitate the particles wthwith violence
it & carry it of from the metall, that is they corrode & eat the metall
And the same particles applied to yethe tongue leave the subtile earth to wchwhich they
adhered before & by a greater attraction rush into the liquids of the tongue agitate
& disjoyne its parts & cause a painfull sensation by reason of wchwhich we call them
acid.
In every solution made by a menstruum, the particles to be dissolved are
more attracted by the particles of the menstruum then by one another; & therefor
leave one another to float in the menstruum.
In every fermentation there is a supprest acid wchwhich is coagulated by precipi
tation upon the body suppressing it
Oyle intimately mixed wthwith a very great quantity of flegm becomes of a
nature something saline & so constitutes vinegre whose acid particles if separated from yethe flegm acid particles would be a volatile salt. Under this head tartar
is also to be considered
Mercury is attracted that is corroded
it opens obstructions, so by it attractive force it draws acids & to it self & suppresses them. suppresses themacids. Mercury is
volatile & rises easily by heat because its particles of the last composition are
small & are easily separated, & being separated endeavour to recede from one
another, as happens also in the particles of vapour & rarefied fluids.
Water cannot be comprest because its particles already touch one another. And if
air was so far comprest as to make its particles touch one another it might be
come a stone.
240
Corpora utiqꝫque omnia densa particulis electricis abundare valde constare videntur & non
nullas etiam habere particulas magneticas. Et attractiones elec quemadmodūum
attractio gravitatis ad majores Planetarum Cometarum Cometarum &
maris nostri motus explicandos sufficit: sic vires electricæ
ad motus minores alios omnes particularum corporum motus expicandos sufficere videntur
ad explicandas actiones et motus particularum inter se corporis cujuscunqꝫque inter se
sufficere videntur; posito scilicet quod particulæ electricæ ad parvas distantias
semper agant fortissime ad magnas vero distantias non agant nisi virtus
earum frictione vel actione vegetandi vel alia aliqua actione cieatur.
Corpus jam comminutum attenuatum & cum particulis acidis inseparabiliter com
mixtum formam veterem amisit & formarum innumerabilium novarum factum est capax
re siquidem particulæ
et in ordinem redigi qu possit, idqꝫque diversimode pro natura corporum viventi
vivorum quibus nutrimentum præbeant. Viva enim
Et hæc vis electrici videtur esse generis propterea quod per motum cietur
& attritionem particularum corporis vegetantiums cieatur. In Corpora utiqꝫque omnia quantum sentio vi electri
ca pollent, & hæc particulæ electricæ ad minimas distantias semper agere possunt
fortissime, & per actiones illas cohærere ubi sese contingunt, & commovere ubi sese
non contingunt diversimode coalescere et cohærere et ubi actio per frictionem particularūum
intenditur vel longius propagatur novis motibus agitari actiones illæ per frictionem
particularum electricæ in fermentatione & vegetatione per frict particularum intendi possunt & longius propagari
et cessante motu remitti. Quinetiam vires magneticæ particularum ferri ad
formationem corporum conducere possunt. Nam particulæ ferri per terrestria
omnia sparguntur.
Quod si aurum naturaliter fermentescere posset, & in fimum putridum ad instar substantiarum ani
malium et vegetabilium abire, idem similiter nutriendo animalia per nutritionem in
corpora per nutritionem in aliud quodvis corpus nutritum posset transformari nutrimentum
præberet animalibus & vegetabilibus & sic posset in aliud quodvis p in omnia
corpora posset transformari. Et similis est ratio mineralium gemmarum et mine
ralium omnium.
Si aurum naturaliter fermentescere posset, idem per putrefactionem ac generationem particulas minimas separantem (ad instar
animalium ac vegetabilium) in aliud quodvis corpus formam suam amittere & in nutriment in fimum & inde abire & subinde per generationem vel nutritionem in aliud quod
ves corpus posset vivum transformari posset. Et similis est ratio gemmarum et mineralium omnium.
Si aurum fermentescere posset [& per p cum fluido quovis disecante per putrefactionem in
particulas minimas resolvi, idem, ad instar substantiarum vegetablium & animalium putrescentium,
formam
rationem] in aliud quodvis corpus vegetando transformari posset. [Et similis est ratio Gemma
rum & mineralium omnium.]
Visciditas est fit per defectum fluiditatis quæ utiqꝫque sita est in partium parvitate qua
lab facile agitaren & labuntur inter se. Intellige partes ultimæ
compositiones. Hujus visciditatis —
Visciditas est imperfecta fluiditas cum attractione partium. Fluiditas autem sita est
in partium parvitate qua facile moveantur & lubricitate qua facile labantur inter se. In
tellige partes ultimæ compositionis. Hujus
Cum acidi particulæ corpus aliquod dissolvunt, hæ particulas corporis poros corporis majores ingrediuntur & singulas corporis ejus particulas externas seipsis utiqꝫque lon
ge majores circumeunt & includunt undiqꝫque ut follicula testa cortex nucleum vel mare terram, & includendo
separant a corpore et in menstruo fluitant Sic corporis unaquæqꝫque et unaquæque corporis particula per mediante aciduom
attractuom & circumposituom in menstruo deinceps fluitat hoc est adeoqꝫque in particulam salis convertitur.
Deinde actione & reactione lenta et continua inter acidum et particu
lam inclusam per fermentationem naturalem excitata, partic acidum
poros particulæ paulatim ingreditur, texturam ejus lente dissolvit, & cum ea tandem miscetur
per minima: Quam operationem putrefactionem dicimus. Compositum vero sic contritum et comminutum formas
novas innumeras induere potest perinde ut Corpus, jam veterem fractum formam veterem amisit & compositum informe sic contritum attenuatum & inseparabiliter comminutum ☉☉ et informe redditum. formarūum novarum innumerarum capax est propterea quod ejus particulæ inter se per novam novam generationem
in particulas majores modis innumeris coalescere possunt.
Nam corporaūum omniaūum particulæ per putrefactionem dividuntur & separantur, coalescunt
congregantur & in particulas majores congregantur coalescunt & in ordinem rediguntur idqꝫque diversimode pro natura viventium quibus nutrimentum præbent
Viva enim per fortem attractionem formam suam et servant et nutrimento paulatim communicant,
at cessante vita cessat attractio vitalis et incipit actio morrum quæ est putr corruptio moriendi quam
corruptionem vel putrefactionem dicimus. Nam quemadmodum vis electrica per frictionem
cietur, & vis magnetica in ferrum Magneti appositum imprimitur transfertur propagatur & vis urendi ab igne in corpora quæ
vis quædam attractiva per fermentationem naturalem cieri
vegetabilis consistit quæqꝫque ideo attractio vitalis dici mereatur, & hæc vis ab actione vivendi conservari et a corpore
vivente in nutrimentum paulatim transferri potest, et cessante vita extingui cessare.
Quæst. Do not all bodies abound with uncertain a very subtile active vibrating spirit by wchwhich
light is emitted reflected & refracted, electric & magnetic attractions & fugations are
performed, the contiguous small particles of bodies cohære when contiguous, & agitate
one another at
as the great bodies of the Universe regulate theirs by the power of
gravity? For electric bodies could not act at a distance without a spirit
reaching to that distance. And by several experiments shewn by Mr Hawksby
before yethe R. Society it appears that a cylindrical rod of glass or hard
wax strongly rubbed emitts an electric spirit or vapour wchwhich may be felt
by the pushes against the hand or face so as to be felt, & upon applica
tion of the finger to yethe electric body crackles & flashes, & that the electric spirit reaches to yethe distance of half a foot or a foot from the glass or above &
electric spirit passes readily through the solid body of a plate or vessel of glass plates, the electric body
attracting things beyond the the glass; & that if a globe of glass being
nimbly turned round upon an axis & in turning rub
excite its electric virtue, the glass emits an electr the hand if the glass
be empty of air shines through the glass wthwith a the
some air be let into the glass, the whole cavity of yethe glass appears
illuminated wthwith flashes of a whiter light; if the air be let in freely
the glass emitts an electric vapour or spirit wchwhich may be felt by the hand & wchwhich
in striking dashing upon the hand or upon white paper or a handkerchief at the distance of a quarter of an inch or half an inch from
the glass or above, illuminates the hand or plaper or handkerchief with
a white light while the glass continues in motion, the vap spirit by
striking upon those bodies being agitated so as to emit the light.
& that if some threds of cotton or worsted yorn hanging by one end at a
little distance from one another be attracted at the other end towards the
glass, & a mans finger be advanced towards the threds attracted ends of
the threds, the threds will recede from the finger, & this they will do
as well when yethe finger they are within the glass as when they are without
it. There is therefore an electric spirit by wchwhich bodies are in some cases
attracted in others repelled & this spirit is so subtile as to p pervades & passes through the solid body of
glass very freely in both cases, & is capable of contraction & dilatation
expanding it self to great distances from the gl electric body by fricti
on, & theforetherefore is elastic & susceptible of a vibrating motion like that
of air whereby sounds are propagated, & this motion is very exceeding quick so
that the electric spirit can thereby emit light. And that wchwhich emits light in the experi
ments above mentioned, may emitts it in all shining bodies whenever sufficiently
agitated either by heat or by putrefaction. And the Medium wchwhich emitts light
may also be able to refract & reflect it as was noted above. And that g This spirit may be also the Medium by
whose vibrating agitations gross stirred up withiinn dense bodies, the bodies receive heat [& conserve it
a long time] & communicate it to contiguous bodies; the vibrations being propaga
ted from the medium in reflected wchwhich being propagated from one body into another
where the bodies are contiguous, but reflected at the surface where they are
not contiguous & by reflections kept within the hot body. The like vibrations
may be excited in the bottom of the eye by light & propagated thence into
the sensorium for through the solid capillamenta of the optick nerves into the sensorium for causing
vision & the like of other senses. The like vibrations may be also
propagated from the brain through the solid fibres of the spinal marrow & its branches into yethe
muscles for agitating & expanding the liquors therein & thereby contracting
the muscles to cause anthe motions of animals. For as liquors are expanded by heat241 by the heat & by & therefore also & by consequence by the vibrating agitations of this
spirit. If the agitations be of short continuance they expand the liquors
without heating them for want of time to do it. If lasting (as in running a race, or in supporting
a burden without external motion of the body) they heat the body by degrees & at length excite sweat. This spirit therefore
seems to may be the medium of sense of animal motion & by consequence of uniting the soul & body thinking soul & unthink
ing body.
[The vegetable life may also consist in the power of this spirit supposing
that this substance is stronger & reaches to a greater distance in in things wchwhich have a
the particles of power in substances wchwhich have a vegetable life then in others is
stronger then in others & reaches to a greater distance from the particles.
For as the electric vertue is stronger in invigorated by friction so it maybe by
some other causes. And by & of gre being stronger in the particles of living substances then in others it
may preserve them from corruption, & [by reaching further from these parti
cles they may] act upon the nourishment to make it of like form & vertue wthwith
themselves living particles as a magnet turns iron into a magn communicates its vertue to
iron turns iron to a magnet & fire turns its nourishment to fire & leaven turns past to leaven.
For the living particles may propagate the vibrating motions of their spirit into
into the contiguous particles of the nourishment & cause yethe spirit in those par
ticles to vibrate & act after yethe same manner & by that action to modify the nourish
ment after the same manner with the living particles.
When The life of a vegetable is in the whole vegetable & in every
part of it. For every banchbranch & every bud & every seed will grow being duly
nourished will grow into a new tree. And in like manner the life
of an animal is in the whole animal female & in every egg of the fe
male. And as the twiggs & budds & seeds of a vegetable tree partake
life of the vegetable tree & have no distinct lives of their own whereby
they can grow into a new vegetable tree untill they be separated from yethe
tree on wchwhich they grow. And as the branch or seed of a tree being
separated from the tree & put into yethe earth where it may receive
due nourishment may grow into a new tree: so the egg of a fema
le being separated from the branch body of the female & converged
into yethe womb & duly nourished may grow into a new animal.
The nourishment of the seed of a plant is the
nourishment This sink
liberty to exercise their vegetable life in retaining & digesting & converting some part of
yethe water into a substance like themselves their own nature. The
nourishment of the seed egg of an animal is the seed of the male & fe
male mixed & fermented together in the act of generation. For all nourishment
of animals is prepared by fermentation. That of adult animals is
fermented by the choler & pancreatic juce both wchwhich come from the
blood. That of the egg an Egg or Embrio therin is the feminine sperm fermented with the
masculine both wchwhich also come from the blood. By fermentation the nourishment is subtilized & replenished
with spirit & put into motion whereby it first acts upon the egg & swells it & makes it fall off from the Ovarium
then is But the egg (or Embrio therein) having a vegetable life is not corrupted by the nourish
ment but overcomes
an animal. In oviparous creatures if the where the white & the yelkyolk of
the egg are the nourishment of the embrio; if the seed of the male doth not
enter the composition of the egg the Embrio will not grow. So then all
for want of due nourishment. So then generation is nothing else then
preparation of due nourishment for making the Embrio begin to grow.
with a life distinct from that of the parents. Before generation it grew as
a parts of the mothers body, By genera & by growing in that manner was shaped into an Embryo (
seeds of trees have young plants in them) after by generation it receives new
nourishment whereby it begins to grow as an animal distinct from is mother.
& the mixture of male & female sperms is only for preparing this nourishment.
242
All bodies seem to be composed of hard particles for otherwise fluids
would not congeale, as water, oyles, Vinegre, & Spirit or oyle of Vitriol do by
freezing, Mercury by fumes of Lead, as Spirit of Nitre & Mercury by dissolving
the Mercury & evaporating the flegm, spirit of wine & spirit of Urin by
deflegming & mixing them & spirit of Urin & spirit of salt by subliming them
together to make salarmoniack. Even the rays of light seem to be hard
bodies, for otherwise they would not retain different properties in their
different sides. And therefore hardness may be recconed the property of all
uncompounded matter. I say uncompounded becomes matter compounded not of hard particles
may be soft or fluid by the sliding of yethe particles amongst themselves [If hard particles of sands
compose soft quicksands, & hard small fragments of the hardest bodies compose soft
powder ] but can never grow hard but matter composed only of soft particles
can never grow hard. can never grow hard
And therefore since all bodies so far as experience reaches are either hard or
hardened, we may conclude affirm from experience that they all consist of hard particles. While & therefore The the har hardening of fluids is an proo plain experimental proof that they
are composed of hard particles. And indeed the simpl uncompounded particles of bodies
seem to be so very hard as never to wear oruniver universal impenetrability of matter For all bodies so far as experience reaches are either hard or may be hardened & we have no other evidence of universal impenetrability besides a large experience without exception. & this Rule, that without experience exceptions are not to be made against the of Nature.A property of all uncompounded matter. This seems to be as evident at least as yethe universal impenetrability
of matter. For all bodies so far as experience reaches are either hard or may be hardened & we have no other evidence of the universal impenetrability of matter than besides a large experienc
without any thing appearing to the contrary. property of all uncompounded matter. At least this seems to be as evident as the univer
sal impenetrability of matter. For all bodies, so far as experience reaches are either
hard or may be hardened & we have no other evidence of universal impenetrability
besides a large experience wthwithout exception. And if compound bodies may be so very hard as
we find some of them to be — — — — their cohesion. And if compound bodies may be so very
hard as we find many of them to be, & yechwhich
are only layed together, the simple bodies particles wchwhich are void of pores & were never yet divided,
must be much harder. For such hard bodies particles being heaped up together can scarce
touch one another in more then a few points & therefore must be separable by much less
force then is requisite to break a solid particle whose parts were never yet separated f touch in all the space between
them wthwithout any pores without any pores or interstices to weaken their cohesion & were never yet ded; And how such very hard bodies particles wchwhich are only laid
together & touch only in points can stick together, & that so firmly as they do, without
the assistance of something wchwhich causes them to be attracted or prest towards one
another is very difficult to conceive.
As in Mathematicks so in Natural Philosophy the investigation of difficult things ought to proceede by Analy
sis ought ever to precede the Composition ought ever to precede their Composition. In the
two first Books I proceeded by Analysis to discover & prove several pro the original differen
ces of the rays of light in respect of their refrangibility reflexibility & colour &
their alternate fits of chwhich
their colours depend: & these discoverys being proved may be assumed as Principles
in the Method of Composition for explaingexplaining their effects phænomena arising from them: an instance of wchwhich Method
I gave in the end of the first Book In this third Book I have only begun the Analysis of what remains to be discovered hinting several thing about light & its effects upon the frame of Nature & leaving the hints to be examined & improved by the further experiments & observations of such as are curious inquisitive.. And because the knowledge of the degrees of heat may be of use in making & reporting some sorts of experiments relating to this matter, I shall conclude with add the following Question.
All these things being considered it seems to me that God [Deus O. M.] in
the beginning created matter in hard solid hard impenetrable moveable
massy particles of such sizes & figures, & with such other
proportion to space as most conduced to the end for wchwhich he created them.
And Tthat these original particles being solids are incomparably harder then any porous
bodies compounded of them; even so very hard as never to weare or break in pieces;
no ordinary
creation. While these particles continue entire they may compound bodies of one
& the same like nature in all ages & texture in all ages; but should they weare or
break in pieces, the nature of things depending on them would be changed.
Water & Earth composed of old worn particles & fragments of particles would
not be of the same nature & texture now with water & earth composed
of entire particles in the beginning22 It seems to me also further ytthat these particles have not only a Vis inertiæ accompanied
wthwith such passive Laws of motion as naturaly result from these that force, but also that they are endued
wthwith certain active Princibples of motions such as is that of gravity & that wchwhich
causes fermentation & the cohedsion of bodies. These principles I consider not
as the occult Qualities resulting from the particular specific forms of things, but as
the general laws of Nature from whence the forms themselves result. To
tell us that every species of things is endowed with an occult quality by wchwhich it acts
is to tell us nothing, but to dening two or three general laws Principles of motion from Phænomena & afterwards to tell us tell us how the properties & actions of all corporeal
things follow from those uniform general Laws Principles would be a very great
step in Philosophy tho the causes of those Principles were not yet discovered yet
therefore I sinple not to propose the Principles of force & motion above mentioned.
Now by the intervention help of these Principles of force & motion all material things seem to have
been composed of the pa hard & solid particles above mentioned variously associated in the first creation, but not
wthwithout the help help of a inter counsel & of an intelligent Agent. For it became
him who created them to set them in order. Of these solid particles all material things
seem to have been composed in the first creation, but not without the inter
vention of an intelligent Agent. For it became him who created them, to
set them in order. And if he did so, its unphilosophical to seek for any
other origin of the world, or to pretend that it might arise out of Chaos
by the mere laws of nature tho being once formed it may continue
in all manner of positions, blind fate could never make all the Planets move one
& the same way in orbs concentrick6. This uniformity must be allowed the effect of
choise. And so the first contrivance of the eyes, ears, brain, heart, lungs, hands, wings,swimming bodies & other organs of sense sense & motion in animals & the instinct of brutes & insects can be the effect of nothing else in animals then the
wisdome & skill of a powerfull ever living Agent who being indivisibly in all places after some such manner
all places as that wchwhich thinks in us is in orour sensorium all parts of our sensorium, perceives all things accurately in their true solid dimensions by the immediate
presence of the things themselves more in his sensorium while that which thinks in us perceives
only the superficial pictures of things made in our sensorium by motion; & who
is more able by his will to move alter & reform the parts of the Universe
forme move the bodies in his sensorium & & thereby to form & reform the parts of the Universe then we are by orour ours to move orour own bodies. And since space is divisible in infinitum
& matter is not necessarily in all places, it must be also allowed that God is able to
of create matter in several parts of yethe Unive particles of matter of several sizes &
figures & in several proportions to space & in several parts of the Universe &
thereby to vary the Laws of Nature, & make worlds of different sorts in several
parts of yethe Universe.
The business of Experimental Philosophy is only to find out by experience &
observation not how things were created but what is the present frame of Nature. This
enquiry should proceed not first by Analysis in arguing from things more known to things less known from things sensible to & particularly from effects to causes & from compo
sitions to their ingredients. And when we have found the Principles out & established any new causes or ingredients of things we may proceed
by Synthesis from these those causes as ingredients as Principles to explain their effects & compositions. Of this
Method I gave an instance in the first book of these Opticks, investigating first by
Analysis the
d original differences of the rays in respect of refrangibility reflexibility
& colours & then from these differences of the
made by Prisms, the colours of the Rainbow & those of natural bodies. I Most of
the second Book was written some years after before the First & so is not in so good a
method. However it proceeds by Analysis to discover the fits of easy reflexion &
easy transmission of the rays, & from thence its easy to compound the explication of the colours of les & other then
transparent plates, &
the Analysis of what remains to be discovered about light, hinting several things about its
nature & effects & leaving the hints to be examined corrected & improved by others the
further experiments & observations of such as are curious, till some further Principles shall be disc
established by wchwhich & the explication of their effects compounded. And by pursuing this method toill we
come to as clear & full a knowledge of the first cause as we can expect from Phænomena, Natural Philoso
phy will be perfected, & a good foundation will be laid for enlarging the bounds
of Moral Philosophy. Fo
243
All bodies seem to be composed of hard particles. for otherwise fluids would not
congeale as water, Byles, vinegre & spirit or oyle of Vitriol, & spirit of Nitre do by freezing, Mercury by
fumes of Lead, & Spirit of Nitre & Spirit of Mercury by dissolving yethe Mercury & evaporating the flegm, spirit of wine & Spirit of Urin by mixing & spirit of Urin & spirit
of salt by compounding subliming to are seem to be hard
bodies for otherwise they would not retain different properties in their different sides.
And thefefore hardness may be recconed the property of all uncompounded matter. I
say uncompounded because compounded matter may be soft or fluid by the sliding
& motion of the p hard particles amongst one another. But as for uncompounded matter there seems
to be the same evidence of its hardness as of its impenetrability: wchwhich evidence is
For we account th but because we find it so by experience in all bodies in wchwhich we can try experiments. [And
that nothing composition is to be admitted in experimental Philosophy but what can be derived from
experiments] Now if bodies simple b And if compound bodies
many of them to be & yet consist of are very porous & consist of parts wchwhich are only layed
together, the simple bodies wchwhich are void of pores & were never yet divided, into parts
must be much harder. Now such hard bodies being heaped up together can only scarce touch
one another only in points in more then points. And how bodies wchwhich touch only
in points can stick together by their own power without attraction is very
difficult to conceive without the assistance of something chwhich causes thēem to be attracted or prest towards one another is very difficult to conceive.
And by pursuing this method in other things as well as in light we may hope by degrees by degrees to discover more & more of the
causes & compositions explications of things & to put the discoveries out of dispute till we come to as clear & full a knowledge of the veyvery first cause
as we can expect from phænomena. And thereby we shal not only perfect Natural Philosophy but also
enlarge the bounds of Moral Philosophy, by founding establishing upon the clear light of Nature the worship of
a Deity as well as the love of orour Neighbour.
All these things being considered, it seems to me that ethe
beginning without any compulsion or necessity) created in (consisting of hard & solid & impenetrable moveable &
other properties & in such proportion to space as most conduced to the ends for wchwhich he
created them. [That these particles are so very hard as never to weare or break in
pieces, for should they were or break for while they continue entire they will be For what power no ordinary power being able to divide what God himself the power of God himself ethe fir creation. For While these particles continue entire they wil be
fit to compound bodies of one & the same nature & texture in all ages, but should they weare
or break in pieces the nature of things depending on them would be changed. Water &
Earth now composed now of entire particles old worn particles & p fragments of particles
would not be the same as in the beginning of the same kind & composition as
in the beginning nature & texture now with water & earth composed of entire particles in the beginning.
Of these particles all material things seem to have been composed in the beginning first creation but not
without the intervention of an intelligent Agent. For it became him that created them to set them in order . And if he did so, its unphilosophical to seek for any other origin of the world or to pretend that it would might arise out of a [which cannot be others then they the earth Planets all For while Comets move in
very excentrick Orbs situated in all manner of positions, blind fate could never
make the orbs of all the Planets move one & yethe same way in orbs concentric. This uniformity must be allowed
as a matter of choise the effect of choise. And so the first contrivance of the eyes h eyes
ears heart must be can be the effect of nothing else
then the wisdome & skill of a powerful ever living Agent who being indivisibly in all places peceivesperceives
all things in their more solid dimensions by their the immediate presence of the things themselves more perfectly than that which thinks in us perceives
its our sensorium by motion, & & who is is more able to move, & govern by his will to move alter & reform them
then rsours to move rour bodies.
[animals of all sorts & man himself without any other further need of a Deity then to
preserve matter & a certain quantity of motion ‖ The business of Experimental Philosophy is only to find out by experience & Observation not how things were created but what are is the present frame of nature. & how her spe
This by Ana first by Analysis in arguing from effects to causes &
from compositions to components ingredients. And when we have found the principles [the causes components ingredients of things we may proceed by
Composition Synthesis I have now from those Principles to explain the things of this method I gave instances in the two first books.
proceeding first by Resolution & then by composition But th in this third Book I have only begun the Analysis of what remains to be deter
found out & discovered, & proved hinting several things here about the nature of light & its effects upon the frame of
Nature, & leaving the hints to be examined & improved by the further experiments & observations of
such as are curious. before And because the knowledge of the degrees of heat may
sometimes be of use in making & reporting of this kind relating to this matter I subjoyned a
shal conclude with the following Question.
The air in wchwhich we breath resists about 10000 times less then quicksilver &if quuicksilver
the vacuum resistance in a glass well emptied of air should be but two hundred times less then
that of yethe open air it would be two millions of times less then that of quicksilver. And in yethe
heavens it would be still much less, there being exp of rarefying airs above
therefore the Vis inertiæ f of yethe matter in the heavens is much above 800 2000000 of times
less ynthan that of quicksilver. &
The Peripateticks in their Ph
Some Philosophers be still should be For these particles I reccon to be hard solid least
I reccon these the least in nature least matter particles hard to be solid, compounded of them should be porous in infinitum
[I reccon them the least in Nature least matter should be actually divided in infinitum &] I reccon
them to be hard & heavy as well, as impenetrable because I meet wthwith equal evidence for all
three Qualities. For we have no other evidence For their being
in all the bodies we can are able to examin, & we have the same evidence for their being hard &
are found hard or may be ‡‡ capable of being hardned. hardened & they are also found heavy. I reccon All sensible bodies here below are or may be hard heavy towards yethe Earth in proportion to the quantity
of matter in each of them. Their gravity in proportion to their matter is not intended or remitted in the same region of the earth by any variety of forms & therefore it cannot be taken away
And I speak of bodies equally distant from yethe center of the earth the by the motions of the celestial bodies it appeares that those bodies are also heavy &
gravitate towards one another in proportion to the matter in each wchwhich is an argument for
universa The whole tenour of experience & observation (wchwhich is very large & without any exception) makes for these
qualities, without any exception that I know of & is without any exception [& experimential all sound Philosophy must be
by experience & & strict true reasoning from phænomena, or & from at least from the analogy
of what we find in Nature & yethe course of Nature] & if the whole course of a large
experience is not a sufficient argument the whole cour universal impenetrability of matter
may be.] When For We have the whole course of a large experience for the universal
gravity & hardness of this part of matter & for yethe hardness of its particles without any instance to the contrary & we have
nothing more the for its universal impenetrability. These particles being solid seem to be so very hard as
as never to wear or break in pieces no ordinary power being able to divide what the al
mighty power of God himself made one in the first creation. While these particles continue entire they
will were be remain fit in all ages to compound bodies of one & the same nature & texture in all ages but should they weare or
so that the resistance seems still to decrease in the same proportion with the density of
the
air wit Quicksilver water & air meet with any other sensible resistance then what arizes from
the denisitydensity & tenacity of those sensible fluids. I [Now yethe air in wchwhich we breath has been rarefied
abou is about
thousand times by drawing it out of glass-vessels as Mr Boyle has shewed. And the
heavens above the Moon are much emptier of air then any vacuum we can make]
Now If the resistance in a vessel well emptied of air was but 100 times less then in
yethe open air it would be about a million of times less then in quicksilver. & But it
seems to be still much less in such a vessel especialy & still much less in the heavens above the orb of the Moon. For Mr Boyle
has shewed that itAir may be rarefied eight or ten thousand times &
it is much rarer then we can m may be accounted are are much emptier of air then any vacuum we can
make below [& so t therefore have much less resistance then & by aris then any such vacuum, we can
make below & by consequence, to be are very much above a million of times rarer & emptier of matter then
quicksilver.] For since the air is comprest by yethe weight of yethe incumbtbent atmosphere & the density of air is proportional to yethe force compressing it
it follows by computation that at yethe height of seven miles from yethe earth yethe
half as dense as twice rarer then at yethe surface of yethe earth & at yethe hight of 14 miles
it is a qua four times rarer then at yethe surface of yethe earth & at yethe height of 21, 28,
35, 42, 49, 56, 63, 70 miles it is 8, 16, 32, 64, 128, 256, 512, 124 1024 it is
times rarer of thereabouts & at the height of 140, 210, 280, 350, 4
miles it is about 1000000, 1000000000, 1000000000000 times rarer & so on
‡ Bodies are therefore resisted in the heavens much less then in any Vacuum we can make below ✝ that is much above a million of times less then in Quicksilver & by consequence the heavens are very much
above a million of times rarer & emptier of matter then any suc Quicks] & therefore
are much emptier
Heat makes many bodies fluid wchwhich are not fluid in cold & increases yethe
fluidity of tenacious fluids as of liquid & basams 2 & oyles, but it increases not
yethe fluidity of water o & thereby decreases that par their resistance: but
it decreases not the resistance of water considerably as it would do
Qu. 24. What are the degrees of heat by wchwhich bodies emitt light
244
Qu. 24 What are the degrees of heat requisite for the yethe emission of
light & wchwhich may be mutually produced by light?
This will be best understood by the following Table
For sulphureous steams ascend frequently out of yethe bowels of the earth & the Air abound
with Nitrous acids fit to promote fermentation as may be peceived by the rusting of iron & copper in it & by the kindling of
fire wthwith a pair of Bellows, & by the dependence of the beating of the heart upon respira
tion.
And even the gross body of Sulphur beaten into pouderpowder & with an equal weight
of iron filings & a little water made into a past, acts upon the iron & in four or
five hours grows too hot to be touched & emits a flame. And by these experiments compared with the warmth of the interior earth & hot springs, burning
mountains, damps earthquakes, hot suffocating exhalations Hurricanes & spouts & thunder & lighting we may learn that
that sulphureous steams abound in the bowels of the earth & Orbits & ferment with minerals &
Qu. 25. Are not the rays particles of light hard bodies & do do not all sensible bodies
consist of hard particles.
ascending into yethe air sometimes take fire & wthwith a great explosion & shaking of the earth burst the caverns in wchwhich
they are sent up & & then the vapor by the explosion expirength through the pores of & earth feels hot & suffocates man
or makes yethe sea bogle & makes sea to bogle & land to glide or sink & yethe sea to bogle & carrys up the water thereof in drops & thick masses wchwhich convening
above wthwith their weight fall down again in spouts. & that at all times that these drops Also some sulphureous steams at all times when
the earth is dry asend ascending into yethe air & there ferment there wthwith nitrous acids & th till take &
sometimes taking fire cause lighting & thunder. For the air abounds with
wchwhich promote fit to promote fermentatitions sulphur, as appears by the rusting of iron the coppper in it & thethe wthwith
a pair of Bellows & by the dependence of yethe beating of the heart by blowing & by the dependence of the beating of the heart upon respiration. And
will
[‡ Nodw all these the above mentioned motions are too so great & violent to cause to be as to shew that in fermentations there is
new motion in the world generated from other Principles then the usual laws of
motion.] Now the above mentioned motions are so great & violent as to
shew that in fermentations bodies wchwhich restalmost rest are put into new motions by a much more
potent principle thaten those laws of motio the Vis ine the laws of motion
& the Vis inertiæ of the matter [& that by this principle new motions]
& very potent active Principle Principle wchwhich is much more potent then the which acts upon bodies them only when they approach one another,
wchwhich is much more potent then are the pass passive laws of motion
arising from the Vis inertiæ of the matter.]
It seems therefore that God has Deus O. M. in the beginning created the hard hard particles of hard matter of
such sizes & figursres & with such other properties & in such a quantity
in proportion to space as most conduced to yethe ends for wchwhich they were created, & of these variously
convening & moveing amongst one another has formed the Universe in corporeal part
of yethe Univers: & that the various changes which forms & changes wchwhich matter dayly puts on undergoes
consists only in the various separations & concretions coalitions & separations of these particles while yethe
particles themselves continue unchanged being too hard to be broken by one
entire as they were at first created & unaltered no ordinary power in nature being able to divide
what God
corporeal nature may continue the same, & produce the same sorts of fluids & solids in all allges but should these be broken into less
particles, the nature of things would be altered. For these broken particles would scarce move &
convene & stick together any more in the same manner & forms as they do at present, unless reunited anew
by a divine power.
I have hitherto proceeded in this Book by way of Analysis, arguing from effects to causes
& from compound bodies to their ingredients. In the two first Books I proceeded first by
Analysis in searching into yethe different refrangibility of the rays & the corresponding
colours of light & then from those Principles compounded the explications of the
colours of light refracted by Prisms those of the Rainbow & those of Natural bodies. In the
second Book I proceeded by Analysis in
& easy transmission of the rays of light, & then from this Principle compounded
a further explication of the colours of & of the constitution of
those bodies requisite for making those The subject of those two books is complein but but that of this third Book is very incomplete. Much remains to be discovered
concerning the nature of Light & fire, much more concerning the nature of fire
& others bodies wchwhich emit reflect, & refract & inflect & & stifle it & concerning
yethe heat, & motion & powers of bodies by wchwhich it is emitted reflected reflected refracted inflected &
stifled. Many experiments are wanting for completing the Analysis of this part of
Nature & coming to a clear & distinct knowledge of all yethe causes of these things, many more for
perfecting the Analysis of all Nature & establishing the making a full & clear
discovery of all the first Principles of Natural Philosophy. And yet To compass this
is a work wchwhich requires many heads & hands & a long time & yet this ought to
be done before we proceed from the first Principles by Composition to explain all
Nature.
some small inconsiderable irregularities excepted wchwhich may have risen from the
actions of Comets & Planets upon one another & wchwhich will be apt to increase
till this systeme wants a reformation. This Such a wonderfull uniformity of in the Planetary Systeme
must be allowed the effect of choise. And so must the uniformity in the bodies of
animal, they having generaly a right side & a left side shaped alike
& on either side of their bodies two leggs behind & two arms or two leggs
or two wings before upon their shoulders & between their shoulders a neck with a head
upon it & in the head two ears, two eyes, a nose, & a mouth, alike situated & a tongue
& teeth alike situated.
— — —Moral Philosophy. For when if we
God, we shall see clearly by the same light of Nature that he is to be feared & praised thanked
& worshipped with wthwith fit expressions of gratitude for the benefits we receive wthwith gratitude & suppli
cation acknowledged feared honoured & & adored.
This Analysis consists in arguing from phænomena to their causes & compositions
& from compositions to ingredients,
from phænomena to their causes, & from immediate particular causes to more general ones
till theto come at the most general argument end in the most general. The Synthesis in assuming the causes discovered & established as principles of PhilophyPhilosophy
& from them expl explaining the Phænomena proceeding from them & proving the Explanations.
In the two first Books of these Opticks I proceeded — — — — inquisitive. And if Natural Philosophy in all its parts by pursuing this method
Natural Philosophy shall at length be perfected, the bounds of Moral Philosophy will be also
enlarged by founding the worship of the first cause upon the light clearest light of Nature
For when we know so far as we shall can know by Natural Philosophy what what dependence power the first cause has over us & what
benefits we or may hope for f or may expect from him, so far our duty towards him as well as that towards one
another will so far appear to us by the clear light of nature. And no doubt, if the worship of
fals Gods had not blinded the Heathens, their Moral Philosophy would have gone further
then to the four Cardinal Vertues, & instead of teaching us to worship the Sun & Moon
& dead mens Souls, they would that tought us the to worship of orour great true Benefactor
These Principles I consider forces are to be chwhich arise from the specific forms of things
but as general Principles by wchwhich the things themselves are formed; & whose wchwhich arise from
causes not yet enquired into explained & whose truth appeares to us us but whose causes
& wchwhich appear to us to be true, but whose causes are not yet explained] their truth appearing
to us Phænomena,, tho their causes be not yet explained.
245
thence it may understood that the parts of all fusible bodies stick together as well in a slate of
fusion as well as in a slate of hardness congelation.
Now the smallest particles of matter
Whence its easy to understand that what ever cause makes the parts of ice & other hard bodies stick together
in a slate of firmnes the same cause will make them stick together when they are
bodies are melted, & tho perhaps not so firmly. For in fusion the parts of bodies
are in a motion of sliding amongsts themselves. & slide upon one another
And so sulphureous & nitrous spirits meeting in the air ferment with violence & make
thunder & lightning.
If equal weights of sulphur poudered & iron filings be make into a past with
a little water, though both yethe ingredients be dry bodies they indissolvable in the water
yet they act upon one another & in five four or five hours grow too hot
to be touched & soon after emit a flame. And thence it may be understood that yethe
sulphureous steams wchwhich abound in yethe bowels of yethe earth meeting wthwith fit matter may
cause great fermentations below & heat mineral waters set mountains on fire & getting out into the air may ferment
& flash with the acids there & its ts with there for causing thunder & lightning. For the air abounds wthwith nitrous acids
wchwhich are very apt to inflame sulphurseous exhalations as be seen by blowing a fire
world. ‖Some other Principle was necessary for putting bodies into motion & after now
they were are in motion some other Principle is necessary for conserving the motion.
For from the various composition of motion — — — warms all things by the light,
Mountains take fire & the inward parts of the earth are constantly warmed & send up generate hot sulphureous healthful
steams exhalations which breaking forth with violence cause earthquakes & tempests & hurricanes, &
raise or subvert Islands & mountains & sink lakes & carry up the sea in spouts columns & in drops & thick mists wchwhich convening above fall down in other again in
spouts. &
Why yethe Barometer stand 60 or 80 inches high.
Why suplphur & iron grow hot & fire & whence Earthquakes Hurricanes & Spouts.
Air promotes yethe burning of sulphureous bodies & therefore apt to make ferment suphureoussulphureous
vapors for causing Thunder & lightning.
The same thing I infer also from the cohering of two polished marbles in Vacuo & from yethe standing of Mercury well at in yethe
barometer at the height of above above 40 or 60 or 70 inches
vided or above when ever it be is will purged of air & carefully poured in so that its
every where contiguous both to one another & to the glass. Some imagin that the
Marbles are prest together by an ambient ætherMercury is prest up into the ambient same Ethereal Medium wchwhich is much subtile then air
& yet cannot permeat pass through the quicksilver. But if this æther can pass through either the Quicksilver or the glass it will
not buy buoy up the Quicksilver Mercury, & if it cannot pass the glass the quicksilver through neither of them then Mercury will not
subside, as it doth when the glass is knocked to make the quicksilver part from it
or when the quicksilver hath any bubbles in it wchwhich hinder the contact & cohesion of its
parts. tment hath been tried with water well purged from Air.
And therefore the parts of water & Quicksilver adhere to one another & to the
glasses by a mutual attraction. If water be congealed by freezing or quicksilver
by the fumes of Lead or by being fried in a frying pan with Virdegris, the parts
of the congealed fluid stick together so as to compose a hard body: & this experimtment
of yethe Barometer shews that they stick together also in a fluid state as well as in a congeled one. And then
Nam calores quos Thermometer calefacta
Thermometer prima vice crepebatuit tanquam si vitrum frangeretur at crepitus post horas tres vel
quatuor cessaaqefacti per
in loco frigido posita temporibus
et calores quos ferrum candens in loco frigido positum temporibus æqualibus amisit erant in
ratione geometrica et inde innotuere per tabular per Tabulam Logarithmorum.
246
the matter nor by any other means then by decreasing the density into
smaller parts & making the parts more smooth & slippery: but that part of the
resistance wchwhich arises from the Vis inertiæ is proportional to the density of the
matter cæteris paribus & cannot be diminished by dividing the matter nor by any other means
then by decreasing the density. And for these reasons the density of fluid Me
diums is very nearly proportional to their resistance. Liquors which differ
not much in density, as water, spirit of vine, spirit of turpentine, hot oyle,
differ not much in resistance. Water is thirteen or fourteen times lighter
then quicksilver & by consequence 13 or 14 times rarer, & its resistance is less
then that of quicksilver in the same proportion or thereabouts, as I have found by
experiments made with Pendulums. The open Air in which we breath is eight or
nine hundred times lighter then water, & by consequence eight or nine hundred
times rarer, & accordingly its resistance is less then that of water in the
same proportion or thereabouts, as I have also fd found by experiments made with
pendulums; & in thinner Air the resistance is still less & at length by rarefying
the Air becomes insensible. For small feathers falling in the open air meet with great
resistance but in a tall glass well emptied of air they fall as fast as lead or
gold as I have seen tried several times. And the heavens above the Moon are emptier of air then
any vacuum we can make below & therefore have less resistance Whence the
resistance seems still to decrease in proportion to the density of the fluid. For I do
not find by any experiments that bodies moving in Quicksilver Water or Air
meet with any other sensible resistance then what arizes from the density
& tenacity of those sensible fluids as they would do if the pores of those fluids & all other spaces were pervaded by a more subtile resisting fluid.. Now if the resistence in a vessel well
emptied of Air was but an hundred times less then in the open Air it
would be about a million of times less then in quicksilver. But it seems to be much
less in such a vessel & still much less in the heavens at the height of three or four
hundred miles from yethe earth or above. For Mr Boyle has shewed that Air may be
rarified above ten thousand times in vessels of glass; & the heavens are much emp
tier of air then any vacuum we can make below. For since the Air is comprest
by the weight of the incumbent atmosphere & the density of Air is proportional
to the force compressing it, it follows by computation that at the height of about seven
miles from the earth the air is twice four times rarer then at the surface of the earth,
& at the height of 14 miles it is four sixteen times rarer then at the surface of the
earth; & at the height of 21, 28, or 35, 42, 49, 56, 63, & or 70 miles it is respectively 64, 256, or 1024, 4096,
16384 128, 256, 512, or 1024 times rarer or thereabouts; & at the height of 70, 140, or 210, or 280
miles it is about 1000000, 1000000000, or 1000000000000 or 1000000000000000000 times rarer, & so on.
Heat promotes fluidity very much by diminishing the tenacity of bodies. It makes
many bodies fluid wchwhich are not fluid in cold & increases the fluidity of tenacious
liquids as of oOyle Balsam & Honey, & thereby decreases their resistance.
decreases not the resistance of water considerably as it would do if any great considerable
part of the resistance of water arose from the attrition or tenacity of its parts
And therefore the resistence of water arises chiefly almost entirely from the Vis inertiæ of its
matter: & by consequence, if the heavens were as dense as water they would
not have much less resistence then water; if as dense as quicksilver they would
not have much less resistence then quicksilver; if absolutely dense or full of
matter without any vacuum, let the matter be never so subtile & fluid, they would
have a greater resistence then quicksilver. A solid globe in such a Medium would
lose above
ter & a globe not solid (such as are the Planets) would be retarded sooner.
And therefore to make way for the lasting & regular motions of the
Planets & Comets, its necessary to empty the heavens of all matter except
perhaps247 perhaps some very thin vapors steams or effluvia arising from the Atmospheres
of the Earth Planets & Comets. Such matter is & such an ethereal Medium as we described above. A dense fluid can be of no use for explaining the
phænomena of Nature, the motions of the Planets & Comets being better
explained without it by gravity without it & gravity not being hitherto
explained by it. It serves only to disturbe & retard the motions of those
great bodies, & make the frame of nature languish & in the pores of
bodies it serves only to stop the vibrating motions of their parts wherein
their heat & activity consists. And as it is of no use & hinders the operations
of Nature & makes her languish, so there is no evidence for its existence
& therefore it ought to be rejected. And if it be rejected, the Hypotheses that
light consists in pression or motion propagated through such a Medium are re
jected with it. And for rejecting such a Medium we have the authority
of those the oldest & most celebrated Philosophers of Greece & Phenicia
who made a Vacuum, Atoms & the gravity of Atoms the first Principles
of their Philosophy; tacitely attributing gravity to some other cause then
dense matter or mechanism. Later Philosophers banish the consideration of such a cause other causes
then mechanism out of natural Philosophy, framing Hypotheses for explaingexplaining all things
mechanically & referring other causes to Metaphysicks: whereas the
main business of natural Philosophy is to argue from Phænomena without
feigning Hypotheses & to deduce causes from effects till we come to the
very first cause which certainly is not mechanical;, & not only to unfold the mechanism of the world
but chiefly to resolve these & such like questions. What is there
in places almost empty of matter, & whence is it that the Sun
& Planets gravitate towards one another without dense matter
between them? Whence is it that Nature doth nothing in vain
& whence arises all that beauty that we see in the world? To
what end are Comets, & whence is it that they move all
manner of ways in orbs Planets move all one & the same way
in orbs concentric while Comets move all manner of ways in
Orbs very excentrick; & what hinders the fixt Stars from falling
upon one another? How come the bodies of animals to be con
trived with so much art, & for what ends were their severall
parts? Was the eye contrived without skill in Opticks & the
ear without the knowledge of sounds? How do the motions of
the body follow from the will, & whence is the instinct in
animals? Is not the sensory of animal that place to which the
sensitive substance is present, & into which the sensible species of
things are carried through the nerves & brain that there they may
be perceived by their immediate presence to that substance?
And these things being rightly determined, dispatcht, dDoes it not appear
from phænomena that there is a Being incorporeal living intellingentintelligent
omnipresent, who in infinite space as it were in his sensory, sees the
things themselves intimately, & throughly perceives them, & comprehends them
wholy by their immediate presence to himself; of wchwhich things the images
only carried through the organs of sense to it self, that wchwhich in us perceives
& thinks, sees & beholds in its little sensorium. And tho every true step
made in this Philosophy brings us not eimmediately to the knowledge of the first
cause, yet it brings us nearer to it, & on that account is to be highly valued.
— tacitely attributing gravity to some other cause then dense matter. the Later
Philosophers banish the consideration of this the supreme cause out of natural Philosophy
framing Hypotheses for explaining all things without it & referring it to
Meph Metaphysicks that is to abstrac reasoning without the help of Phenomena or reasoning in the dark: whereas the main business of natural Philosophy is
to argue from effects to causes till we come to yethe very first cause, & not only to
unfold the mechanim of the world but chiefly to resolve these & such like questions
What is there in places almost empty of matter & whence is it that the Sun & Planets
gravitate towards one another without dense matter between them? Whence is it that
Nature does nothing in vain ethe
world? To wtwhat end are Comets & whence is it that they move all manner of ways in Orbs very excentric & Planets all one way in obs
concentric, & what hinders the fixt stars from falling upon one another? How come the bodies of animals to be contrived with so much art? & for
what ends were their several parts? Was yethe eye contrived without skill in
Opticks & yethe ear without the knowledge of sounds? To what end are Comets?
whence is it that their Orbs are very eccentrical & those of Planets concentrical? & what hinders the fixt stars from falling upon one another. & how do yethe motions of the body follow from yethe will & whence is the instinct in animals? And tho
every true step made in this Philosophy brings us not immediately to the first cause
knowledge of the first cause yet it brings us nearer to it & on that account is
to be highly valued.
248
Qu 23. Have not the small partciles of bodies certain powers virtues or forces
by wchwhich they act at a distance not only upon the rays of light for reflecting refra
cting & inflecting them but also upon one another for producing a great part of yethe
phænomena of nature? [For it has been shewed that bodies act upon the rays of
light at a distance in refracting reflecting & inflecting them, & by the phænomena of
Island Crystal it appears that some bodies act upon light by two sorts of powers
one of wchwhich is an usual & an unusual one, the last of wchwhich is something like magneti
cal attraction. That we may find out by what powers bodies act on light at a distance
I have propounded this Question for fending all the powers by wchwhich the particles of
bodies act onat ona distance on one another]. For its well known that they bodies act one
upon another by the attractions of gravity magnetism & electricity & these in
stances shew the course & tenour of nature & make it not improbable but that there may
be more attractive powers then these. These powers reach to very sensible distances
& so have been observed by vulgar eyes, & there may be others wchwhich reach to so small distances as hitherto to escape
observation. ‡ ‡ Or that bodies may act at very small distances act by electricall attraction even witoutwithout friction For Nature is very consonant & conformable to her self. How these
attractions are or may be performed I do not here consider. What I
call attraction may be performed by impulse or by some other means
unknown to me. I use that word here to signify only in general any
force by wchwhich bodies tend towards one another whatever be the cause.
For we must learn from the phænomena of Nature what bodies do
attract one another at a & what are the laws & properties of the attra
ctios before we enquire the cause by wchwhich the attraction is performed.
The attractions of gravity magnetism & electricity reach to very
sensible distances & so have been observed by vulgar eyes & there
may be others wchwhich reach to so small distances as hitherto to escape
observations, & perhaps electrical attraction may reaclreach to small distances even without being excited by friction.
For when salt of Tartar runs — — — —
For when salt of Tartar runs per deliquium is not this done by
an attraction between the particles of the salt of Tartar & the particles of water
wchwhich float in the air in the form of vapors? And why does not common salt or
saltpeter or vitriol run per deliquium but for want of such an attraction?
Or why does not salt of Tartar draw more water out of the air then in a
certain proportion to its quantity, but for want of an attractive force after
it is satiated with water? And whence is it but from this attractive power
that water wchwhich alone distills with a gentle lukewarm heat will not destill
from salt of Tartar without a great heat? And is it not from the like
attractive power between the particles of oyle of Vitriol & the particles of
water that Oyle of Vitriol draws to it a good quantity of water out
of the air, & after it is satiated draws no more, & in destillation lets go
the water very difficultly? And when water & oyle of Vitriol poured successive
ly into the same vessel grow very hot in the mixing, does not this heat argue
a great motion in the liquor parts of the liquors? & does not this motion argue
that the parts of the two liquors in mixing coalesce with violence & by conse
quence rush towards one another with an accelerated motion. And when Aqua fortis or Spirit of Vitriol
poured upon filings of iron dissolve the filings with a great heat & ebulliti
on
& does not that motion argue that the acid parts of the liquor rush towards
the parts of the metal with viloence, & run forcibly into its pores till they
get round its outward particles between its outmost particles & the main mass of yethe
metal & surrounding those particles loosen them from the main mass & set them at liberty to flote off from
the main mass into yethe water? And when the acid particles wchwhich alone would
destill with an easy heat will not separate from the particles of the metal without
a very violent heat does not this confirm the attraction between them?
When salt of Tartar per deliquium being poured into the solution of any
metal precipitates the metal & makes it fall down to the bottom of the
liquor in the form of mud, does not this argue that the acid particles are
attracted more strongly by the salt of Tartar then by the metal & by the
stronger attraction go from the metal to the salt of Tartar? And so when
a solution of copper in Aqua fortis dissolves dissolves the Lapis Calaminasis & lets go the iron or a solution of Copper dissolves iron immersed in it & lets go
the copper, or solution of Silver dissolves Copper & lets go the silver or249 or a solution of Mercury in aqua fortis being poured upon iron copper tin or
lead dissolves the metal & lets go the Mercury, does not this argue that the
acid particles of the Aqua fortis are attracted more strongly by the Lapis Calamiriaris then by Iron & more strongly by iron then by the Lapis Calaminasis ynthen by
copper & more strongly by copper then by silver & more strongly by iron,
copper tin & lead then by Mercury? And is it not for the same reason that
iron takes up more A requires more Aqua fortis to dissolve & satiate it then copper
& copper more then silver the other metals; & that of all metals iron is dissolved
most easily & is most apt to rust; & next after iron, copper?
When spirit of Vitriol poured upon common salt or saltpeter
makes an ebullition with the salt & unites with it & in destillation the
spirit of yethe common salt or saltpeter comes over much easier then it
would do before & the acid part of the spirit of Vitriol stays behind; does
not this argue that the fixed Alcaly of the salt attracts the acid spirit
of the Vitriol more strongly then its own spirit, & not being able to hold
them both, lets go its own? And when oyle of Vitriol is drawn off from its
weight of Nitre & from both the ingredients a mixed compound spirit of Nitre is destilled two parts of wchwhich
being poured on one part of oyle of cloves or larvy seeds, or of any ponderous vegetable oyle or oyle of animal substances, or oyle of Turpentine thickened wthwith a little balsam of sulphur, grows so very hot in mixing as presently to send up
a burning flame: does not this very great & sudden heat argue that the
parts of the two liquors
run towards one another with an accelerated motion & clash with the greatest
force? And is it not for the same reason that well rectified spirit of wine poured on the said
of sulphur Nitre & salt of Tartar goes off with a more sudden & violent explo
sion then Gun-powder, the acid spirits of the Sulphur & Nitre rushing towards
one another & towards the salt of Tartar with so great a violence as by the shock to turn
the whole at once into vapour & flame? Where the dissolution is
slow it makes a slow ebullition & with a gently heat & where it is
quicker it makes a greater ebullition with a gentler more heat, & where
it is done at once, the ebullition is contracted into a sudden blast
or violent explosion with a heat equal to that of fire & flame.
not from a mutual attraction that the spirits of soot & sea
salt sublimation unite & compose the particles of Solar monta So when a drachm of the above mentioned compound spirit of Nitre was poured upon half a drachm of oyle of Carvi seeds in Vacuo the mixture immediately made a flash like gunpowder & burst the exhausted Receiver wchwhich was a glass six inches wide & eight inches deep. And ‡
‡ And so sulphureous & nitrous spirits meeting in the Air ferment & flash with violence
& cause thunder & lightning
‡And even the gross bo
weight of iron filings & a little water made into a past, acts
upon the iron & in four or five hours five or six hours grows too
hot to be touched & emits a flame. And by these experiments com
pared with the great quantity of sulphur wthwith wchwhich the earth abounds
& the warmth of the interior parts of the earth & hot springs &
burning mountains, & with damps mineral corruscations, earthquakes, hot suffocating exha
lations, hurricanes & spouts; we may learn that sulphureous steams
abound in the bowels of the earth & ferment with minerals
& sometimes take fire with a sudden corruscation & explosion & if
pent up in subterraneous caverns burst the caverns with a
great shaking of the earth as in springing of a mMine, & then
the vapor generated by the explosion expiring through the pores
of the earth feels hot & suffocates & makes tempests & hurricanes
& sometimes causes the land to slide or the sea to boyle & carries
up the water thereof in drops wchwhich by their weight fall down again
in spouts. Also some steams sulphureous steams, at all times when the
earth is dry, ascending into the Air, ferment there with nitrous acids, &
sometimes taking fire cause lightning & thunder & fiery Meteors. For the Air abounds
with acid vapors fit to promote fermentations, as appears by the rusting
of iron & copper in it, the kindling of fire by blowing, & the beating of the heart the heart by means of respiration. Now the above mentioned motions are
so great & violent as to shew that in fermentations the particles of bodies wchwhich almost
rest are put into new motions by a very potent principle wchwhich acts upon
them only when they approach one another & causes them to meet &
clash with great violence & grow hot with the motion & dash one another into pieces & vanish into
air & vapour & flame.
When Oyle of Vitriol is mixed with a little water or is run per deli
quium & in destillation the water ascends difficultly & brings over with
it some part of the Oyle of Vitriol in the form of spirit of Vitriol
& this spirit being poured upon iron copper or salt of Tartar
unites with the body & lets go the water, does not this shew that the
acid spirit is attracted by the water & more attracted by the fixt body
then by the water & therefore lets go the water to close with the
fixt body? And is it not for the same reason that the water & acid
spirits in Vinegar, Aqua fortis & Spirit of Salt cohere & rise together
in destillation; but if the Menstruum be poured on salt of Tartar,
or on Lead or Iron or any fixt body wchwhich it can dissolve, the acid by
a stronger attraction adheres to the body & lets go the water? And is it
not also from a mutual attraction that yethe spirits of soot & sea salt unite
& compose the particles of Salarmoniac wchwhich are less volatile then before because
grosser & freer from water; & that the particles of Salarmoniac in sublimation carry up
the particles of Antimony wchwhich will not sublime alone; & that
of Mercury uniting with the acid particles of spirit of salt compose Mercury sub
limate, & with the particles of sulphur compose cinnaber; & ytthat the particles of spirit
of wine & spirit of uchwhich dissolved them
compose a body consistent & almost fixed body;; & that in subliming cinnaber from Salt of250 of tartar or quick lime the sulphur by a stronger attraction of the salt
or lime lets go the Mercury & stays with the fixt body, & ytthat when Mercury
sublimate is sublimed from Antimony or from Regulus of Antimony,
the spirit of salt lets go the Mercury & unites wthwith the Antimoni
al metal wchwhich attracts it more strongly & stays with it till the heat
be great enough to make them both ascend together, & then carries
up the metal with it in the form of a very fusible salt called
butter of Antimony, although the spirit of salt alone be almost as vo
latile as water & the Antimony alone as fixt as lead?
When Aqua fortis dissolves silver & not gold & aAqua regia dissolves
gold & not silver may it not be said that Aqua fortis is subtile enough
to penetrate Gold as well as silver but wants the attractive force to give
it entrance, & that Aqua regia is subtile enough to enter penetrate silver as well as Gold but
wants the attractive force to give it entrance. For Aqua regia is
nothing else then Aqua fortis mixed with some spirit of salt or with
salarmoniac & even common salt dissolved in Aqua fortis enables the
menstruum to dissolve Gold tho the salt be a gross body. When there
fore spirit of salt precipitates silver out of Aqua fortis is it not
done by attracting & mixing with the Aqua fortis & repelling the not attracting or pehrhaps or perhaps repelling the
silver; & when water precipitates Antimony out of the sublimate
of Antimony & Salarmoniac or out of butter of Antimony is it
not done by dissolving mixing with & weakning the salarmoniac or spirit
of salt & repelling not attracting or perhaps repelling the Antimony? And is it not from the want of an
attractive vertue between the parts of water & oyle, of Quicksilver
& Antimony, of Lead & Iron that these substances do not mix & by
a weak attraction that quicksilver & copper mix difficultly & from a
strong one that Quicksilver & Tin, Antimony & iron, water & salts
mix readily? And in general, is it not from the same principle,
that heat congregtates homogeneal bodies & separat
When Arsenick with soap gives a Regulus & with Mercury sublimate
a volatile fusible salt like butter of Antimony, does not this shew
that Arsenick is compounded of fixt & volatile parts strongly cohering
by a mutual attraction so that the volatile will not ascend without
carrying up the fixed? And so when an equal weight of spirit of
wine & oyle of Vitriol are digested together & in destillation yeild
two fragrant volatile spirits which will not mix with one another
& a fixt black earth remains behind, doth not this shew that
oyle of Vitriol is composed of volatile & fixed parts strongly united
by attraction so as to ascend together in form of a volatile acid fluid
salt, untill the spirit of wine attracts & separates the volatile parts
from the fixed? And therefore since oyle of Sulphur per campanam
is of the same nature: with oyle of Vitriol, may it not be inferred
that sulphur is also a mixture of volatile & fixed parts so strongly
cohering by attraction as to ascend together in sublimation. By
By dissolving flowers of Sulphur per in oyle of Turpentine & de
stilling the solution, it is found that sulphur is composed of an in
flammable volatile thick oyle] or fat bitumen, an acid salt, a very fixt
earth & a little metal. The three first were found not much unequal
to one another, the fourth in so small a quantity as scarce to be worth
considering. The acid salt dissolved in water is the same with oyle of
sulphur per campanam, & abounding much in the bowels of the earth
& particularly in Markasites, unites it self to the other ingredients of
the Markasite, wchwhich are bBitumen, Iron, Copper & earth & with them
compounds Alume Vitriol & Sulphur. With the earth alone it com
pounds Alume, with the metal alone or metal & earth together
it compounds Vitriol, & with the Bitumen & Earth it compounds Sulphur
whence it comes to pass that Markasites abound with those three mine
rals. And is it not from the mutual attraction of the ingredients that
they stick together for compounding these minerals, & that the Bitumen
carries up the other ingredients of the sulphur, wchwhich without it would not
sublime? And the same Question may be put concerning all or almost all
the gross bodies in nature. For all the parts of animals & vegetables
are composed or partsicles substances volatile & fixed fluid & solid as appears by their
Analysis, & so are salts & minerals so far as Chymists have been
hitherto able to examin their composition
When Mercury sublimate is resublimed with fresh Mercury & becomes
Mercurius dulcis wchwhich is a white tastless earth scarce in dissolvable in water, and251 and Mercurius dulcis resublimed with spirit of salt returns into Mercury
sublimate & when Metals corroded with a little acid turn into rust wchwhich
is an sort of tastless earth an earth tastless & indissolvable in water &
this earth satiated imbibed with more acid become a metallic salt
& when some stones, as spar of Lead, dissolved in proper menstruums
become salts, does not these things shew that salts are dry earth & watry acid
united by attraction, & that f the earth will not become a salt without
so much acid as makes it be earth dissolvable in water? And as gravity ✝
✝Doe not the sharp & pungent tasts of acids arise from the strong attra
ction whereby the acid particles rush upon & agitate the particles of the
tongue? And when metalls are dissolved in acid menstruums do not the
acids adhering & the metallic particles lose much of their activity
& act the acids in conjunction wthwith the metal after act after a different manner
so that the compound has a different tast much milder then before
& sometimes a sweet one is it not because the acids adhere to the metallick particles & thereby lose much of their activity?? And if the acid be in too small a pro
portion to make the compound dissolvable in water, will it not by
adhering strongly to yethe metal become unactive & lose its tast & yethe
compound be a tastless earth? For such things as are not dissolva
ble by the moisture of the tongue act not upon the tast.
As gravity makes the sea flow round makes the sea flow rowndround the denser & weightier parts of the globe
of the earth so the attraction may make the watry acid flo
the denser & compacter particles of earth for composing the particles of
salt. For otherwise the acid would not do the office of a mediatorum between
the earth & common water for making salts dissolvable in the water
nor would salt of tartar readily draw off the acid from dissolved metalls.
nor metals the acid from Mercury. Now as in the great globe of the earth & sea the densest bodies by gra
vity sink down in water & always endeavour to go towards the center of
the globe so in particles of salt the densest matter will always endeavour
to approach the center of the particle: so that a particle of salt may
be compared to a chaos, being dense hard dry & earthy in the center &
& rare soft moist & watry in the circumference. And hence it seems
to be that salts are of a lasting nature being scarce destroyed unless
by drawing away their watry parts by violence or by letting them
soak into the pores of the central earth by a gentle heat in putrefaction
untill the earth be dissolved by the water & separated into smaller par
ticles wchwhich by reason of their smalness make the rotten compound appear
of a black colour. Hence also it may be that the parts of animals
& vegetables preserve their several forms & assimilate their nourish
ment, the soft & moist nourishment easily changing its texture by a gentle
heat & motion till it becomes like the dense hard dry & durable earth
in the center of each particle. But when the nourishment grows
unfit to be assimilated or the central earth grows too feeble to assimi
late it, the motion ends in putrefaction & death.
If a very small quantity of any salt or Vitriol be dissolved in a great
quantity of water the particles of the salt or Vitriol will not sink to
the bottom tho they be heavier in specie then the water but will
eavenly diffuse themselves into all the water so as to make it as saline
at the top as at the bottom. And does not this imply that the parts of
the salt or Vitriol recede from one another & endeavour to expand
themselves & get as far asunder as the quantity of water will allow
in wchwhich they float? And does not this endeavour imply that they have a
repulsive force by wchwhich they fly from one another or at least that
they attract the water more strongly then they do one another? For
as all things ascend in water wchwhich are less attracted then water by the gra
vitating power of the earth, so all yethe particles of salt wchwhich float in water & are
less attracted then water by
particle & give way to the more attracted water
When any saline liquor is evaporated to a cuticle & let cool, the
salt concretes in regular figures, wchwhich argues that the particles of salt before252 before they concreted, floated in the liquor at equal distances in rank & file
& by consequence that they acted upon one another by some power wchwhich
at equal distances is equal at unequal distances unequal. For by such a
power they will range themselves uniformly & without it they will
float irregularly & come together as irregularly. And since the particles
of Island Crystal act all the same way upon the rays of light for causing
the unusual refraction, may it not be supposed that these in the formation
of this crystal the particles not only ranged themselves in rank & file
for concreting in regular figures but also by some kind of polar vertue turned
their homogeneal sides the same way.
The parts of all homogeneal hard bodies wchwhich fully touch one another
stick together very strongly. And for explaining how this may be some
have invented hooked atoms which is begging yethe question; & others tell us that bodies are glued together
by rest i.e. by an h which are utterly unintelligible occult Quality, or rather by nothing, & others that they stick together by conspiring motions, that is, by rest amongst themselves.: but I had rather infer from their cohesion that their parti
cles attract one another by some force wchwhich in immediate contact is ex
ceeding strong, at small distances performs the chymical operations
above mentioned & reaches not far from the particles wthwith any sensible
effect. All bodies seem to be composed of hard particles, for otherwise fluids would not congeale, as water, oyles, Vinegre, & spirit or oyle of Vitriol do by freezing, Mercury by fumes of Lead, Spirit of Nitre & Mercury by dissolving the Mercury & evaporating the flegm, spirit of Wine & spirit of Urine by deflegming & mixing them, & spirit of Urine & spirit of salt by subliming them together to make salarmoniac. Even the rays of light seem to be hard bodies, for otherwise they would not retain different properties in their different sides. And therefore hardness may be recconed the property of all uncompounded matter. At least this seems to be as evident as the universal impenetrability of matter. For all bodies, so far as experience reaches, are either hard or may be hardened, & we have no other evidence of universal impenetrability besides a large experience without exception. Now if compound bodies may be are so very hard as we find some of them to be & yet are very porous & consist of parts wchwhich are only laid together the simple particles wchwhich are void of pores & were never yet divided must be much harder. For such hard particles being heaped up together can scarce touch one another in more then a few points & therefore must be separable by much less force then is requisite to break a solid particle whose parts touch in all the space between them wthwithout any pores or interstices to weaken their cohesion. And how such very hard particles wchwhich are only laid together & touch only in a few points can stick together, & that so firmly as they do, wthwithout the assistance of something wchwhich causes tmthem to be attracted or prest towards one another, is very difficult to conceive. The same thing I infer also from the cohering of two polished marbles in Vacuo, & from the standing of Quicksilver in the Barometer at the height of 50 60 or 70 inches or above whenever it is well purged of air & carefully poured in, so that its' parts be every where contiguous both to one another & to the glass. Some imagin that the Quicksilver Marbles are prest together by an ambient æther, & that the Quicksilver is prest up into the Tube by the same æther. But if this æther can pass through either the Quicksilver☞ or the glass it will not press the Quicksilver up into the glass & if it can pass through neither of them it will not let the Quicksilver subside, as it doth whenever the glass its knocked to make the Quicksilver part from it or whenever the Quicksilver hath any bubbles in it wchwhich hinder the contact & cohesion of its parts. Yet if the æther be rarer between the particles then in open & free spaces, it may press them together by its excess of density. The like experiment hath been tried with water well purged of æther Air from air. If Quicksilver or Water be congealed by the fumes of Lead or water be congealed by freezing, the parts of the congeled fluid stick together so as to compose a hard body: & by this experiment of the Barometer it appears that they stick together also in a state of fluidity. Whence its easy to understand that what ever cause makes the parts of ice & hard metalsls stick together amongs the same cause will makes them stick together when the bodies are melted, tho perhaps not so firmly. For in fusion the parts of bodies are in a motion of sliding amongst themselves. And of the same kind with these experiments is this experiment that water ascends in very slender glass pipes (even in Vacuo as soon as the lower ends of the pipes are dipped into yethe stagnant water; & the narrower are the pipes, the greater is the ascent. And there is the same cause of philtration, An> & of the ascent of water in the form of an Hyperbola between two planes of glass inclined to one another in a very acute angle & dipt perpendicularly into the liquor, whether the experiment be tried in the open air or in vacuo.
Now the smallest particles of matter may cohere by the strongest attractions & compose bigger particles of weaker vertue &c Now the smallest particles of matter may cohere by the strongest attractions and compose And thus nature will be very conformable to her self & very simple, performing all the great motions of the heavenly bodies by the attraction of gravity wchwhich intercedes those bodies & almost all the small ones of their particles by some other attractive power wchwhich intercedes the particles bigger particles of weaker vertue & many of these may cohere & compose bigger particles whose vertue is still weaker & so on for divers successions untill the progression end in the biggest particles on wchwhich the operations in chymistry & the colours of natural bodies depend, & wchwhich by cohering compose bodies of a sensible magnitude. If the body is compact & bends or yeilds inward to pression without any sliding of its parts, it is hard & elasticAnd thus Nature will be very conformable to her self & very simple, performing all the great motions of the heavenly bodies by the attraction of gravity wchwhich intercedes those bodies & almost all the small ones of their particles by some other attractive powers wchwhich intercedes the particles returning to its figure with a force arising from the mutual attraction of its parts. If the parts slide upon one another the body is malleable or soft. If they slip easily & are of a fit size to be agitated by heat & the heat is big enough to keep them in agitation, the body is fluid, & if it be apt to stick to things it is humid; & the drops of every fluid affect a round figure by ‡ ‡ the mutual attraction of their parts as the globe of yethe earth & sea affects a round figure by the mutual attraction of its parts by gravity.
Since metals dissolved in acids attract but a small quantity of the acid, their attractive force can reach but to a small distance from them. And as in Algebra, where affirmative quantities vanish & cease there negative ones begin: so in Mechanicks, where attraction ceases there a repulsive vertue ought to begin succeed. And that there is such a vertue seems to follow from the reflexions & inflexions] of the rays of light. For the rays of are repelled by bodies in both these cases without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of light, the ray so soon as it is shaken off from a shining body by the vibrating motion of the parts of the body & gets beyond the reach of attraction, being driven away with exceeding great velocity. For that force wchwhich is sufficient to turn it back in reflexion may be sufficient to emit it. It seems also to follow from the production of air & vapor: The particles when they are shaken off from bodies by heat or fermentation so soon as they are beyond the reach of the attraction of the body, receding from ✝& whose Idæas work more powerfully upon fit matter then the Imagination of a mother works upon an Embrios, or that up of a man upon his body for promoting health or sickness: it254 it & also from one another with great strength, & keeping at a distance. # # so as sometimes to take up above a million of times more space then they did before in the form of a dense body. Which vast contraction & expansion seems unexplicable unintelligible by feigning the particles of Air to be springy & ramous or rolled up like hoops, or by any other means then a repulsive power. The particles of fluids wchwhich do not cohere too strongly & are of such a smalness as renders them most susceptible of those agitations wchwhich keep liquors in a fluor, are most easily separated & rarefied into vapour, & in the language of the Chymists they are volatile, rarefying with an easy heat & condensing with cold. But those wchwhich are grosser & so less susceptible of agitation or cohere by a stronger attraction are not separated without a stronger heat or perhaps not without fermentation And these last are the bodies wchwhich Chemists call fixed & being rarefied by fermentation become true permanent air: those particles receding from one another with the greatest force & being most difficulty brought together wchwhich upon contact cohere most strongly. And because the particles of permanent air are grosser & arise from denser substances then those of vapors, thence it is that true air is more ponderous then vapor & that a moist Atmosphere is lighter then a dry one quantity for quantity, as is found by the Barometer. ☉ ☉ & by thin glass bubbles sealed hermetically, wchwhich being poised in a very nice pair of scales, descend in a most Air & ascend in a dry one. From the endeavour of the particles of Air to recede from one another & from dense bodies it comes to pass also that Air is rarer in very slender pipes of glass then in free spaces & by reason of its rarity presses less upon the surface of water into wchwhich the lower end of the pipe is dipped then the open air presses upon it & so gives leaves to the water to ascend in the pipe: wchwhich is the ground of philtration. From the same repelling power it seems to be that flys walk upon water without wetting their feet; & that the Object-glasses of long Telescopes lye upon one another without touching; & that dry pouders are difficultly made to touch one another by compression so as to stick together, unless by melting them or wetting them with water wchwhich by exhaling may brings them together, & that two polished Marbles wchwhich by immediate contact stick together are difficultly brought so close together as to stick.
And thus Nature will be very conformable to her self & very simple, performing all the great motions of the heavenly bodies by the attraction of gravity wchwhich intercedes those bodies, & almost all the small ones by of their particles by some other attractive & repelling power wchwhich intercedes the particles. And while these powers are of so large an extent, I do not see but that they may be numbered among the general laws of motion. The Vis inertiæ is a passive principle by wchwhich bodies persist in their motion or rest, receive motion in proportion to the force impressing it, & resist as much as they are resisted. By this principle alone there could never have been any motion in the world. Thinking will are active principles by wchwhich we move orour bodies according to orour will, & thence arise other laws of motion unknown to us, wchwhich, if & if there be an universal life & all space the Universe be the sensorium of a thinking Being, (for Nature does nothing in vain) those laws may be of universal extent. Gravity was recconed among the laws of motion by the ancient Philosophers who attributed gravity to their atoms in vacuo as the first Principle of their Philosophy.. And the forces above mentioned by wchwhich small bodies act on one another at small distances may have as good a title as gravity to be recconed among those laws ‖ Life ‖ Life & Will are active Principles by wchwhich we move orour bodies, according to & thence arise other Laws of motion not yet known to us. And since all matter duely formed by generation & nutrition is attended with signes of life, & all things are framed with perfect art & wisdome, & Nature does nothing in vain; if there be an universal life, & all space be the sensorium of āan immaterial living thinking Being, who by immediate presence perceives things in it as that wchwhich thinks in us perceives their pictures in the brain, : the laws of motion arising from Life or Will may be of universal extent. Gravity &c
But while I call these forces attraction or repulse, I would not be understood to define the cause or manner of the action. That wchwhich I call the Attraction may be done by impulse or by some other means unknown to me. I only use that word to signify a force by wchwhich bodies tend towards one another as what ever be the cause Some other Principle was necessary for putting bodies into motion, & now they are in motion some other Principle is necessary for conserving the motion. motion For Ffrom the various composition of two motions tis very certain that there is not always the same quantity of motion in the world. For if two globes joyned by a slender rod revolve about their common center of gravity with an uniform motion while that center moves on uniformly in a right line drawn in the center plane of255 of their circular motion, the summ of the motions of the two globes as often as the globes are in the right line drawn in described by their com̄mmon center of gravity will be bigger then the summ of their motions when they are in a line perpendicular to that right line. By this instance it appears that motion may be got or lost; Bbut by reason of the tenacity of fluids & attrition of their parts & the weakness of elasticity in solids, motion is much more apt to be lost then got, & is always upon the decay. For bodies wchwhich are either so absolutely hard or so soft as to be void of elasticity, will not rebound from one another. Impenetrability makes them only stop. If two equal bodies meet directly in vacuo they will be the laws of motion stop where they meet & lose all their motion & lose all their motion & continue to rest, unless they be elastick & receive new motion by from their spring. If they have so much elasticity as suffices to make them rebound with half a quarter or half or three quarters of the force wthwith wchwhich they came together they will rebound with half as much motion as they had before they met the other half being lost lose half their motion lose lose three quarters or half or a quarter of their motion. And this may be tried with by letting two equal pendulums of Lead or soft Clay & letting them fall f against one another from equal heights. If the pendulums be of lead or soft clay they will lose all or almost all their motion: if of elastic bodies, they will lose all but what they recover from their elasticity. If three equal round vessels be filled the one with water the other with oyle the third with molten pitch & the liquors be stirred about alike to give them a vortical motion: the pitch by its tenacity will lose its motion quickly, the oyle being less tenacious will keep it longer & the water being least tenacious will keep it longest but yet will lose it in a short time. Whence its easy to understand that if many contiguous Vortices of molten pitch were each of them as large as the Cartesian, yet these & all their parts would by their tenacity & stifness communicate their motion to one another till they all rested among themselves. Vortices of oyle or water or some fluider matter might continue longer in motion but unless the matter were void of all tenacity & attrition of parts & communication of motion (wchwhich is not to be supposed) the motion would constantly decay. Seing therefore the variety of motion wchwhich we see in the world is always decreasing, there is a necessity of conserving & recruiting it by active principles; such as are [the power of life & will by which animals move their bodies with great & lasting force;] the cause of gravity by which Comets & Planets & Comets keep their motions in their Orbs & allall bodies acquire great motion in falling; & the cause of fermentation by wchwhich the heart & blood of animals are kept in pepetualperpetual motion & heat, the inward parts of the earth are constantly warmed, & the inward parts of the earth are constantly warmed bodies burn & shine, mountains take fire, the caverns of the earth are blown up & the Sun continues violently hot & lucid & warms all things by his light., For we meet with very little motion in the world besides what is oweing to these active principles and & therefore we ought to inquire diligently into the general Rules or Laws observed by nature in the preservation or production of motion by these principles as the Laws of motion on wchwhich the frame of Nature bdepends & the genuine Principles of Mechanical Philosophy & the inward parts of the earth are constantly warmed & generate hot sulphureous unhealthful exhalations wchwhich breaking forth with violence cause earthquakes, tempests, & hurricanes, raise or subvert Islands & Mountains, sink Lakes & carry up the sea partly in columns, & partly in drops & thick mists wchwhich convening above fall down in spouts, & sulphureous steams set mountains on fire & the inward parts of the earth are constantly warmed. For we meet with very little motion in the world besides what is visibly oweing to these active principles, & the power of the will
All these things & 257
Qu. 21. Are not the rays of light very small bodies emitted from shining substances & refracted by mean of certain attractions which intercede them & the parts of pellucid bodies. For such bodies will pass through uniform Mediums in right lines without bending into the shadow, wchwhich is the property nature of the rays of light. Pellucid substances S They will also conserve their original be capable of several properties & be able to conserve their properties unchanged wchwhich is another prop in passing through several Mediums, wchwhich is another condition of the rays of light. Pellucid substances act upon the rays of light at a distance in refracting reflecting & inflecting them & the rays mutualy agitate the parts of those substances at a distance for heating them; & this action & reaction at a distance very much resembles an attractive force. If refraction be performed by attraction of the rays, the sines of incidence must be to the sines of restfraction in a given proportiōon as we shewed in orour Principles of Philosophy, & this Rule is true by experien experience. If The rays of light in going out of glass into a Vacuum are bent towards the glass, and if they fall too obliquely on the Vacuum they are bent backwards into the glass & totaly reflected, wchwhich & this reflexion cannot be ascribed to the resistance of the Vacuum, but must be caused by the power of the glass attracting the rays at their going out of it glass into the Vacuum & bringing them back. into the glass For if the further surface of the glass be moistened with water or clear oyle or liquid & clear honey, the rays will go through the glass into wchwhich would otherwise be reflected will go into the water oyle or honey, & therefore are not not reflected not before they arrive at the further surface of the glass but when th & begin to go out it into yethe Vacuum of it. If they go out of it into water or oyle or honey they go on, being because the attraction of the glass being is almost ballanced & rendred ineffectual by the contrary attraction of the water or oyle liquor; but if they go out of th it into a vacuum wchwhich has no attraction to ballance that of the glass, the attraction of the glass either bends & refracts them or brings them back & reflects them. ✝ ✝And this is still more evident by compressing laying together two Prisms together one of wchwhich is plane, the other a very little convex, of Glass or two Object glasses of very long Tlelescopes the one plane the other a little convex, so that the glasses & so compressing them that they do not fully touch but have an interval between them wchwhich is less then the ten hundred thousanthdth part of an inch. a nor are too far asunder. For the light wchwhich falls upon the further surface of the first glass will go through it into yethe second glass where the interval between yethe glasses is not above the ten hundred thousandth part of an inch will go through that surface & through the air air or or vacuum between the glasses & enter into the second glass as was explained in the 1st 4th & 8th Observations of the first pPart of the second Book.
But if the second glass be taken away the light will not go on forward but tr wchwhich goes out of the second surface of the first glass into yethe air or vacuum Air or Vacuum will not go on forward but turns back into yethe 1st glass & is reflected; & therefore it is drawn back back by the power of the first glass there being nothing else to bring it back into yethe glass stop it to cause it to turn back. For if the further surface of yethe glass be plane & well polished & behind it be place the convex Object-glass of a very long Telescope so that yethe least distance between the glasses be less then the ten hundred thousandth part of Nothing more is requisite for producing all the variety of colours & degrees of refrangibility then that the rays of light be bodies of different sizes, the least of wchwhich may make violet the weakest & darkest of colours & be more easily diverted by refracting surfaces from the right course, & the rest as they are bigger & bigger may make the stronger & more lucid colours blue green yellow & red, & be more & more difficultly diverted. Nothing more is requisite for putting the rays of light into fits of easy reflexion & easy transmission then that they be small bodies wchwhich by their attractive powers or some other force stir up vibrations in what they act upon, wchwhich vibrations being swifter then the rays, overtake them & successively & agitate them so as by turns to increasieng & decreasieng their velocitityvelocity & thereby putting them into those fits. And lastly the unusual refraction of Island Crystal looks very much as if it were performed by some kind of attractive vertue lodged in certain sides both of the rays & of the particles of yethe crystal. For were it not for some kind of disposition or vertue lodged in some sides of the particles of the crystal wchwhich is & not in their other sides, & wchwhich inclines & bends the rays towards the coast of unusual refraction; the rays wchwhich fall perpendicularly on the crystall would not be refracted towards that coast rather then towards any other coast both at their incidence & at their emergence, so as to emerge perpendicularly by a contrary situation of the coast of unusual refraction at the second surface; the crystal acting upon the rays after they have past through it & are emerging into the air, or, if you please, into a vacuum. And since258 since the crystal by this disposition or vertue does not act upon the rays unless when one of their their sides of unusual refraction looks towards that coast, this argues a vertue or disposition in those sides of the rays wchwhich answers to & sympathizes with that vertue or disposition of the crystal, as the poles of two magnets almost as the poles of two Magnets answer to one another. And as magnetism may be intended & remitted, & is found only in the Magnet & in iron: so this vertue of refracting the perpendicular rays is greater in Island Crystal less in Crystal of the rock & is not yet found in other bodies. I do not say that this vertue of is magnetical: It seems to be of another kind. And I only say that what ever it be, its difficult to conceive how the rays of light unless they be bodies can have a permanent vertue in two of their sides wchwhich is not in their other sides & this without any regard to their position to the space or medium through wchwhich they pass. 259
Qu. 22. Are not gross bodies & light convertible into one another: & may not bodies receive their activity from the rays particles of light wchwhich enter their composition? For all fixt bodies being heated emit light so long as they continue sufficiently hot, & light mutualy stops in bodies as often as its rays strike upon their parts, as we shewed above. I know no body less apt to shine then water, & yet water by frequent destillations changes into fixed earth & this earth as Mr Boyle has tried & then this earth being enabled to endure a sufficient heat shines as much by heat as any like other bodyies. The changing of light into bodies into light & light into bodies is very conformable to the course of nature, which seems delighted with transmutations Water, wchwhich is a very fluid volatile tastless salt, she changes by heat into vapour wchwhich is a sort of air, & by cold into ice wchwhich is a hard pellucid brittle fusible stone: & this stone returns into water by heat & vapour returns into water by cold. Earth by heat becomes fire & by cold returns into Earth. Dense bodies by fermentation rarefy into several sorts of air & this air by fermentation & sometimes without it returns into dense bodies. Mercury appears sometimes in the form of a fluid ponderous running Mercury a fluid metal, sometimes in the form of a hard brittle metal, sometimes in the form of a corrosive pellucid salt called sublimate, sometimes in the form of a tastless pellucid volatile white earth called Mercurius dulcis, or in that of a red opake volatile earth called Cinnaber, or in that of a red or white precipitate, or in that of a fluid salt, & In destillation it turns into vapour. & Being agitated in vacuo it shines like fire. And being dropt into a red hot earthen Retort it destills in the form of common water pellucid & tastless And after all these & other changes it returns again into Mercury. Eggs grow from insensible magnitudes & change into animals, Tad-poles into Frogs & worms into Flyes. All Birds Beasts & Fishes Insects Trees & other Vegetables with their several parts, grow out of water & watry tinctures & salts, & by putrefaction return again into watry substances. And destilled water standing a few days in the open air yeilds a tincture which (like that of Mault) by standing longer yeilds an sediment & a spirit, but before putrefaction is fit nourishment for animals & vegetables. And among such various & strange transmutations why may not Nature change bodies into light & light into bodies?
Now attraction in bodies of the same kind & vertue attraction is strongest in the smallest bodies in proportion to their bulk. It is found stronger in small magnets for their weight then in great ones. For the parts of small ones being closer together unite their forces more easily. And therefore since the rays of light are the smallest bodies known to us we may expect to find their attractions very strong. And how strong they are may be gathered by this proportion Rule. The attraction of a ray of light in proportion to the body quantity of its matter is to the gravity of a projectile in proportion to its body the quantity of its matter in a compound ratio of the velocity of the ray of light to the velocity of the projectile twice & of the bent or curvity of the ray in the place of refraction to the bent or curvity of the line described by the projectile supposing the inclination of the ray to the ray to the refracting surface & that of the projectile to the horizon to be alike. And by this proportion I reccon the attraction of the rays of light to be above 260 ten hundred thousand thousand millions of times greater then the weight of bodies on the surface of this earth in proportion to the matter in them, supposing that light comes from the sun to us in about seven or eight minutes of times an hour. And in immediate contact of the rays their force may be still much greater. And so great a force in the rays cannot but have a very great effect upon the particles of matter with wchwhich they are compounded for causing the particles to attract one another & for putting them in motion amongst them another themselves: for the better understanding of which I will propose the following Quæstion.
261
Qu. 17. If a stone be thrown into stagnating water, the undulations waves excited thereby continue some time to begin arise in the place where the stone fell into the water, & are propagated from thence in concentric circles upon the surface of the water to great distances. And the vibrations or tremors excited in the Air by percussion continue a little time to move from the place of percussion in concentric shpheres to great distances. And in like manner when a ray of light falls upon the surface of any pellucid body & is there refracted or reflected: may not the vibrations be thereby excited in the refracting or reflecting Medium at the point of incid incidence, & continue to arise there & to be propagated from thence as long as when they are excited in the bottom of the eye by the pressure & motion of the finger, or by the light wchwhich comes from the coale of fire in the experiments above mentioned? And are not these vibrations propagated from the point of incidence to great distances? from And do they not overtake the rays of light, & by overtaking them successively, do they not put them into the fits of easy reflexion & easy transmission described above? For if the rays endeavour to recede from the densest part of the vibration they may be alternately accelerated & retarded by the vibrations overtaking them.
Qu. 18. If in two large & tall cylindrical vessels of glass inverted, two little Thermometers be suspended so as not to touch the vessels; & the air be drawn out of one of these vessels, & these vessels thus prepared be carried out of a cold place into a warm one: the Thermometer in vacuo will grow warm as much & almost as soon as the Thermometer which is not in vacuo. And when the Vessels are carried back into the cold place, the Thermometer in vacuo will grow cold almost as soon as the other Thermometer. Is not the heat of the warm room conveyed through the Vacuum by the vibrations of a much subtiler Medium then Air, which, after the Air iwas drawn out, remained in the Vacuum? And is not this Medium the same with that Medium by wchwhich light is refracted & reflected, & by whose vibrations light communicates heat to bodies & is put into fits of easy reflexion & easy transmission? ☉ ☉ And Do not the vibrations of this Medium in hot bodies, contribute to the duration of their heat? And do not hot bodies communicate their heat to contiguous cold ones by the vibrations of this Medium propagated from them into the cold ones? And is not this Medium exceedingly more rare & subtile then the Air & exceedingly more elastic & active? And doth not this æthereal Medium readily pervade all bodies? And is it not by its elastic force expanded through all the heavens?
Q. 19. Doth not the refraction of light proceed from the different density of this æthereal Medium in different places, the light receding from the denser parts of the Medium? & being totally in passing through glass or crystall & in passing thro falling very obliquely upon the further surface of the glass or crystal being totally reflected by means of the density of this Medium without the glass or crystall? And is not the density thereof greater in free & open spaces void of Air & other grosser bodies, then within the pores of water glass crystal gemms & other compact bodies? For when light passes through glass or crystall & falling very obliquely upon the further surface thereof is totally reflected thereby, the total reflexion ought to proceed rather from the density & vigour of the Medium without & beyond the glass, then from the rarity & weakness thereof.
Qu. 20. Doth not this Æthereal Medium in passing out of water glass crystal & other compact substances & dense bodies into empty spaces & grow denser & denser by degrees, & by that means refract the rays of light not in a point but by bending them gradually in curve lines? And doth not the gradual condensation of this Medium extend to some distance from the bodies, & thereby cause the inflexions of the rays of light which pass by the edges of compact bodies at some distance from the bodies? 262
Qu. 21. Is not this Medium much rarer within the dense bodies of the Sun, Starrs, Planets & Comets, then in the celestial spaces, without between them, & in passing from them to great distances doth it not grow denser & denser perpetually & thereby cause the gravity of those great bodies towards one another, & their parts towards the bodies; every body endeavouring to go from the denser parts of the Medium towards the rarer? For if this Medium be rarer within the Sun's body then at its surface, & rarer there then at the distance of the hundredth part of any inch from its body, & rarer there than at the tenth part of an inch from its body, & rarer there then at the orb of Saturn: I see no reason why the increase of density should stop any where & not rather be continued through all distances from the Sun to Saturn, & beyond. And tho this increase of density may at great distances be exceeding slow yet if the elastick force of this Medium be exceeding great, it may suffice to impell bodies from the denser parts of the Medium towards the rarer with all that power which we call gravity. And that the elastick force of this Medium is exceeding great, may be gathered from the swiftness of its vibrations. Sounds move about 1140 English feet in a second minute of time, & in seven or eight minutes of time they move about one hundred English miles. Light moves from the Sun to us in about seven or eight minutes of time, wchwhich distance is about 70000000 English miles, supposing the horizontal Parallax of the Sun to be about 12″. And the vibrations or pulses of this Medium, that they may cause the alternate fits of easy transmission & easy reflexion, must be swifter then light, & by consequence above 700000 times swifter than sounds. And therefore the elastick force of this Medium must be in proportion to its density must be above 700000 x 700000 times greater then the elastic force of the Air is in proportion to its density. For in elastic Mediums of equal density, the elasticity is must be in a duplicate ratio of the velocity of the pulses. And if the density be increased or diminished & the elasticity must be increased or diminished in the same proportion, that the velocity will remain the same & in those of unequal density the velocity if the elasticicityelasticity & density be encreased or decreased in one & the same proportion the velocity will remain the same.
Qu. 22. May not Planets & Comets & all other gross bodies perform their motions with more freely & with much less resistance than in a fluid den in this Æthereal Medium then in a fluid supposed by some to be denser than quicksilver? wchwhich fills all space adequately without leaving any pores, & by consequence is much denser then quicksilver or gold? And may not its resistance be so small as to be inconsiderable? For instance: If this Æther (for so I will call it) should be supposed 700000 times more elastick then Air & above 700000 times more rare; its resistance would be above 600000000 times less then that of water. And so small a resistance would scarce make any sensible alteration in the motions of the Planets in ten thousand years. If you any one would ask how any Medium can be so rare, let him tell me first how the Air be 16000 times rarer then gold can be in the upper parts of the Atmosphere can be above 1000000 ten hundred thousand times rarer then gold.
Qu. 23. Is not vision performed by the vibrations of this Medium excited in the bottom of the eye by the rays of light & propagated through the solid pellucid & uniform capillamenta of the auditory optic nerves into the place of sensation? And is not hearing performed by the vibrations either of this or some other Medium excited in the auditory nerves by the tremors of the Air & propagated through the solid pellucid & uniform capillamenta of those nerves into the place of sensation? And so of the other senses. I suppose the capillamenta of the nerves taken singly, to be pellucid that they may be uniform. But the ‖‖ But the reflexions of light in the surfaces of the capillamenta cause the nerves themselves to appeare white & opake.
Qu. 24. Is not animal motion performed by the vibrations of this Medium excited in the brain by the power of the will, & propagated from thence through the solid pellucid & uniform capillamenta of the nerves into the muscles for contracting & dilating them? I suppose the single capillamenta of the nerves to be solid & uniform & pellucid that the motion may be propagated uniformly along them uniformly & without interruption. For obstructions in the Nerves create Palsies. And that they may be uniform, I suppose them when viewed singly to be pellucid, tho the reflexions in their surfaces may make the whole nerve appear opake & white (composed of a great number of capillamenta) appear pellucid & opake & while. For if the capillamenta be not continued pellucid the reflexions of light from their inward parts, will argue that those parts are not continued but are distinguished from have reflecting surfaces by wchwhich they are interrupted bounded & distinguished from one another.
Qu. 23.
The force of the resistance arises only from the density of the Medium & is proportionall to yethe □ of yethe velocity of the moving body & & will not put a resting body into motion. the force of gravity is here deduced only from the elasticity of the medium, & from the variation of it density & without any regard to the velocity of the body & may put a resting body into motion. And while these two forces depend upon different causes, the one may be very small while & the other very great.
Resistance & Gravity are here ascribed to different causes; [resisistanceresistance arises from to yethe density of yethe Medium & velocity of the body, gravity to the variation of elasticity] gr the one to the variation of elasticity, the other to the
And if any / And yet yethe elasticity for causing gravity may be exceeding great.
& by consequence exceedingly less able to resist the motions of projectiles & exceedingly more able to press upon the pa gross bodies by endeavouring to expand it self.
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Qu. 17. If a stone be thrown into stagnating water, the waves excited there by continue some time to arise in the place where the stone fell into the water, & are propagated from thence in concentric circles upon the surface of the water to great distances. And the vibrations or tremors excited in the Air by percussion continue a little time to move from the place of percussion in concentric spheres to great distances. And in like manner, when a Ray of light falls upon the surface of any pellucid body & is there refracted or reflected may not waves of vibrations or tremors be thereby excited in the refracting or reflecting Medium at the point of incidence & continue to arise there & to be propagated from thence as long as they continue when they are excited in the bottom of the eye by the pressure or motion of the finger or by the light which comes from the coale of fire in the experiments above mentioned? And are not these vibrations propagated from the point of incidence to great distances? And do they not overtake the rays of light, & by overtaking them successively do they not put them into the fits of easy reflexion & easy transmission described above? For if the rays endeavour to recede from the densest part of the vibration, they may be alternately accelerated & retarded by the vibrations overtaking them.
Qu. 18. If in two large tall cylindricall vessels of glass inverted, two little Thermometers be placed suspended so as not to touch the vessels, & the Aer be drawn out of one of these vessels, & these vessels thus prepared be carried out of a cold place into a warm one: the Thermometer in vacuo will grow warm as much & almost as soon as the Thermometer which is not in vacuo. And when the Vessels are carried back into the cold place, the Thermometer in vacuo will grow cold almost as soon as the other Thermometer. Is not the heat of the warm room conveyed through the Vacuum by the vibrations of a much subtiler Medium then Air, wchwhich after the Air was drawn out remained in the Vacuum? And is not this Medium the same with that Medium by which light is refracted & reflected, & by whose vibrations light communicates heat to bodies, & is put into fits of easy reflexion & easy transmission? And do not not the vibrations of this Medium in hot bodies contribute to the intenseness & duration of their heat? And do not hot bodies communicate their heat to contiguous cold ones by the vibrations of this Medium propagated from them into the cold ones? And is not this Medium exceedingly more rare & subtile then the Air & exceedingly more elastick & active? And doth it not readily pervade all bodies? And is it not (by its elastic force) expanded through all the heavens?
Qu. 19. Doth not the refraction of light proceed from the different density of this æthereal Medium in different places, the light receding always from the denser parts of the Medium? And is not the density thereof greater in free & open spaces void of Air & other grosser bodies then within the pores of water glass crystal gemms & other compact bodies? For when light passes through glass or crystal & falling very obliquely very obliquely upon the further surface thereof is totally reflected, the total reflexion ought to proceed rather from the density & vigour of the Medium without & beyond the glass, than from the rarity & weakness thereof.
Qu. 20. Doth not this æthereal Medium in passing out of water glass crystal & other compact & dense bodies into empty spaces grow denser & denser 264 & denser by degrees, & by that means refract the rays of light not in a point but by bending them gradually in curve lines? And doth not the gradual condensation of this Medium extend to some distance from the bodies & thereby cause the inflexions of the rays of light which pass by the edges of dense bodies at some distance from the bodies?
Qu. 21. Is not this Medium much rarer within the dense bodies of the Sun Stars Planets & Comets then in the empty celestial spaces between them, & in passing from them to great distances doth it not grow denser & denser perpetually & thereby cause the gravity of those great bodies towards one another, & of their parts towards the bodies; every body endeavouring to go from the denser parts of the Medium towards the rarer? For if this Medium be rarer & was e within the Sun's body then at its surface, & rarer there then at the hundredth part of an inch from its body, & rarer there then at the fiftith part of an inch from its body, & rarer there then at the Orb of Saturn: I see no reason why the increase of density should stop anywhere & not rather be continued through all distances from the Sun to Saturn & beyond. And tho this increase of density may at great distances be exceeding slow, yet if the elastick force of this Medium be exceeding great, it may suffice to impell the bodies from the denser parts of the Medium towards the rarer with all that power wchwhich we call gravity. And that the elastick force of this Medium is exceeding great may be gathered from the swiftness of its vibrations. Sounds move about 1140 English feet in a second of a minute of time, & in seven or eight minutes of time they move about one hundred English miles. Light moves from the sun to us in about seven or eight minutes of time, wchwhich distance is about 70000000 English miles, supposing the horizontal Parallax of the Sun to be about 12″. And the vibrations or pulses of this Medium, that they may cause the alternate fits of easy transmission & easy reflexion, must be swifter then light, & by consequence above 700000 times swifter then sounds. And therefore the elastick force of this Medium in proportion to its density must be above 700000 x 700000 times greater then the elastick force of the Air is in proportion to its density. For in elastic Mediums, of equal density the elasticity must be is in a duplicate ratio of the velocity of the pulses. And in those of unequal density, if the elasticity be proportional to the density the velocity will remain the same.
Qu. 23. Is not vision performed by the vibrations of this Medium excited in the bottom of the Eye by the rays of light & propagated through the solid pellucid & uniform capillamenta of the optick nerves into the place of sensation? And is not hearing performed by the vibrations either of this or some other Medium excited in the auditory nerves by the tremors of the Air, & propagated through the solid pellucid & uniform capillamenta of those nerves into the place of sensation? And so of the other senses. ‡ ‡ For the velocities of the pulses of elastic Mediums are in a subduplicate ratio of the elasticities & the rarities of the Mediums taken together.
As attraction is stronger in small magnets then in great ones in proportion to their bulk, & gravity is greater in the surfaces of small planets then in those of great ones in proportion ot their bulk, & small bodies are agitated much more by electric attraction then great ones: so the smallness of the rays of light may contribute very much to the power of the agent by which they are refracted. And so if any one should suppose that Ether (like our air) may contein particles which endeavour to recede from one another (for I do not know what this Æther is) & that its particles are exceedingly smaller then those of air, or even then those of light: the exceeding smallness of its particles may contribute to the greatness of the force by which those particles may recede from one another, & thereby make that Medium more exceedingly more rare & elastic then Air, & by consequence exceedingly less able to resist the motions of projectiles & [exceedingly more able to press upon gross bodies by endeavouring to expand it self.
Qu. 22. May not Planets & Comets & all gross bodies perform their motions more freely & with much less resistance in this æthereal Medium then in any fluid wchwhich fills all space adequately without leaving any pores, & by consequence is much denser then quicksilver or gold? And may not its resistance be so small as to be inconsiderable? For instance. If this Æther (for so I will call it) should be supposed 700000 times more elastic then orour Air & above 700000 times more rare; its resistance would be above 600000000 times less then that of water. And so small a resistance would scarce make any sensible alteration in the motions of the Planets in ten thousand years. If any one would ask how a Medium can be so rare; let him tell me how the Air in the upper parts of the Atmosphere can be above ten an hundred hundredthousand thousand times rarer then Gold.
Qu. 23. Is not vision performed by the vibrations of this Medium excited in the bottom of the eye by the rays of light, & propagated through the solid pellucid & uniform capillamenta of the optick nerves into the place of sensation? And is not hearing performed by the vibrations either of this or some other Medium excited in the auditory nerves by the tremors of the Air, & propagated through the solid pellucid & uniform capillamentamenta of those nerves into the place of sensation? And so of the other senses.
Qu. 24. Is not animal motion performed by the vibrations of this heart Medium excited in the brain by the power of the will, & propagated from thence through the solid pellucid & uniform capillamenta of the nerves into the muscles for contracting & dilating them? I suppose that the motion vibrating motion of the ethereal Medium may be propagated along them from one end to the other uniformly & without interruption For obstructions in the Nerves create palsies. And that they may be sufficiently uniform I suppose them to be pellucid when viewed singly, tho the reflexions in their cylindrical surfaces may make the whole nerve (composed of many capillamenta) appear opake & white. For opacity arises from reflecting surfaces, such as may disturbe & interrupt the motions.
Qu. 25. Are there not other original properties of the rays of light besides those already described? An instance of another original property we have in the refraction of Island Crystal described first by Erasmus Bartholine & afterwards more exactly by Hugenius in his Book De la lumiere. This crystal is a pellucid fissile stone clear as water or crystal of the rock, & without colour; enduring a red heat without loosing it's transparency, & in a very strong heat calcining without fusion. Steeped a day or two in water it looses its natural transparency polish. Being rubbed on cloth it attracts pieces of straws & other light things like Ambar or Glass: & with Aqua fortis it makes an ebullition. It seems to be a sort of Talk & is found in form of an oblique Parallelopiped [with six parallelogram sides & eight solid angles. The obtuse angles of the Parallelogramms are each of them 101 degrees & 52 minutes; the acute ones 78 degrees & 8 minutes. Two of the solid angles opposite to one another, as C & E, are compassed each of them with three of these obtuse angles, & each of the other six with one obtuse & two acute ones. It cleaves easily in planes parallel to any of its sides, & not in any other planes. It cleaves with a glossy polite surface not perfectly plane but with some little uneavenness. It is easily scratcht, & by reason of it's softness it takes a polish very difficultly. It polishes better upon polished looking-glass then upon metal, & perhaps better upon pitch leather or parchment. Afterwards it must be rubbed with a little oyle or white of an egg to fill up its scratches: whereby it will become very transparent & polite. But for several experiments, it is not necessary to polish it. If a piece of this crystalline stone be laid upon a book, every letter of the Book seen through it will appear double by means of a double refraction. And if any beam of light falls either perpendicularly or in any oblique angle upon any surface of this crystal, it becomes divided into two beams by means of the same double refraction. Which beams are of the same colour with the incident beam of light, & seem equal to one another in the quantity of their light, or very nearly equal. One of these refractions is performed by the usual Rule of Opticks, the sine of iIncidence out of Air into this Crystal being to the sine of Refraction, as five to three. The other Refraction, which may be called the unusual Refraction, is performed by the following Rule.
Let ADBC represent the refracting surface of the crystall, C the biggest solid angle at that surface, GGCHF the opposite surface, & CK a perpendicular on that surface. This perpendicular makes with the edge of the crystal CF an angle of 19degr. 3′. Ioyne KF & in it take KL so that the angle CKL KCL be 6degr. 40′, & the angle LCF 12degr. 28′. And if ST represent any beam of light incident at T in any angle upon the refracting surface ADBC, let TV be the refracted beam266 beam determined by the given proportion of the sines 5 to 3 according to the usual rule of Opticks. Draw VX parallel & equal to KL. Draw it the same way from V in which L lieth from K; & joyning TX, this line TX shall be the other refracted beam carried from T to X by the unusual refraction.
If therefore the incident beam ST be perpendicular to the refracting surface, the two beams TV & TX into which it shall become divided, shall be parallel to the lines CK & CL; one of those beams going through the crystall perpendicularly as it ought to do by the usual laws of Opticks, & the other TX by an unusual refraction diverging from the perpendicular & making with it an angle VTX of about 6 degrees, as is found by experience. And hence the plane VTX & such like planes which are parallel to the plane CFK, may be called the planes of perpendicular refraction. And the coast towards which the lines KL & VX are drawn, may be called the coast of unusual refraction.
In like manner Crystal of the rock has a double refraction: but the difference of the two refractions is not so great & manifest as in Island crystall.
When the beam ST incident on Island Crystal, is divided into two beams TV & TX, & these two beams arrive at the further surface of the glass; the beam TV which was refracted at the first surface after the usual manner, shall be again refracted entirely after the usual manner at the second surface; & the beam TX which was refracted after the unusual manner in the first surface shall be again refracted entirely after the unusual manner in the second surface: so that both these beams shall emerge out of the second surface in lines parallel to the first incident beam ST.
And if two pieces of Island Crystall be placed one after another in such manner that all the surfaces of the latter be parallel to all the corresponding surfaces of the former: the rays which are refracted after the usual manner in the first surface of the first crystall shall be refracted after the usual manner in all the following surfaces: & the rays which are refracted after the unusual manner in the first surface shall be refracted after the unusual manner in all the following surfaces. And the same thing happens tho the surfaces of the crystalls be any ways inclined to one another, provided that their planes of perpendicular refraction be parallel to one one another.
And therefore there is an original difference in the rays of light by means of wchwhich some rays are in this Experiment constantly refracted after the usual manner, & others constantly after the unusual manner For if the difference be not original but arises from new modifications imprest on the rays at their first refraction it would be altered by new modifications in the three following refractions: whereas it suffers no alteration but is constant & has the same effect upon the rays in all the refractions. The unusual refraction is therefore performed by an original property of the rays. And it remains to be enquired whether the rays have not more original properties then are yet discovered.
Qu. 26. Have not the rays of light several sides endued with several original properties? For if the planes of perpendicular refraction of the second crystall, be at right angles with the planes of perpendicular refraction of the first crystall: the rays wchwhich are refracted after the usual manner in passing through the first crystall will be all of them refracted after the unusual manner in passing through the second crystall; & the rays wchwhich are refracted after the unusual manner in passing through the first crystall will be all of them refracted after the usual manner in passing through the second crystall. And therefore there are not two sorts of rays differing in their nature from one another, one of which is constantly & in all positions refracted after the usual manner, & the other constantly & in all positions after the unusual manner.267 manner. The difference between the two sorts of rays in the Experiment mentioned in the 25th Question, was only in the positions of the sides of the rays to the planes of perpendicular refraction. For one & the same ray is here refracted sometimes after the usual & sometimes after the unusual manner according to the position which its sides have to the crystalls. If the sides of the rays are posited the same way to both crystalls, it is refracted after the same manner in them both: but if that side of the ray which looks towards the coast of the unusual refraction of the first crystall be 90 degrees from that side of the same ray which looks towards the coast of the unusual refraction of the second crystall, (which may be effected by varying the position of the second crystall to the first, & by consequence to the rays of light the ray shall be refracted after several manners in the several crystalls. There is nothing more required to determin whether the rays of light which fall upon the second crystall shall be refracted after the usual or after the unusual manner, but to turn about this crystal so that the coast of this crystalls unusuall refraction may be on this or on that side of the ray. And therefore every ray may be considered as having four sides or quarters, two of which opposite to one another incline the ray to be refracted after the unusual manner as often as either of them are turned towards the coast of unusual refraction, & the other two whenever either of them are turned towards the coast of unusual refraction, do not incline it to be otherwise refracted then after the usual manner. The two first may therefore be called the sides of unusual refraction. And since these dispositions were in the rays before their incidence on the second third & fourth surfaces of the two crystalls, & suffered no alteration (so far as appears) by the refraction of the rays in those surfaces their passage through those surfaces, & the rays were refracted by the same laws in all the four surfaces; it appears that those dispositions were in the rays originally, & suffered no alteration by the first refraction, & that by means of those dispositions the rays were refracted at their incidence on the first surface of the first crystal, some of them after the usual & some of them after the unusual manner, accordingly as their sides of usual re unusual refraction were then turned towards the coast of the unusual refraction of that crystal or sideways from it.
Every ray of light has therefore two opposite sides originally endued with a property on which the unusual refraction depends, & other two opposite sides not endued with that property. And it remains to be enquired whether there are not more properties of light by wchwhich the sides of the rays differ & are distinguished from one another.
In explaining the difference of the sides of the rays above mentioned, I have supposed that the rays fall perpendicularly on the first crystall. But if they fall obliquely on it, the success is the same. Those rays which are refracted after the usual manner in the first crystall will be refracted after the unusual manner in the second crystall; supposing the planes of perpendicular refraction to be at right angles with one another as above: & on the contrary.
If the planes of the perpendicular refraction of the two crystalls be neither parallel nor perpendicular to one another but contein an acute angle: the two beams of light which emerge out of the first crystall, will be each of them divided into two more at their incidence on the second crystall. For in this case the rays in each of the two beams will some of them have their sides of unusual refraction & some of them their other sides turned towards the coast of the unusual refraction of the second crystall.
Qu. 27. Are not all Hypotheses erroneous which have hitherto been invented for explaining the phenomena of light by new modifications268fications of the rays? For those phenomena depend not upon new modifications as has been supposed, but upon the original & unchangeable properties of the rays.
Qu. 28. Are not all Hypotheses erroneous in which light is supposed to consist in pression or motion propagated through a fluid Medium? For in all these Hypotheses the phænomena of light have been hitherto explained by supposing that they arise from new modifications of the rays: which is an erroneous supposition.
If light consisted only in pression propagated without actual motion it would not be able to agitate & heat the bodies wchwhich refract & reflect it. If it consisted in motion propagated to all distances in an instant it would require an infinite force every moment in every [shining particle to generate that motion. And if it consisted in pression or motion propagated either in an instant or in time it would bend into the shadow. For pression or motion cannot be propagated in a fluid in right lines beyond an obstacle which stops part of the motion, but will bend & spread every way into the quiescent Medium wchwhich lyes beyond the obstacle. Gravity tends downwards, but the pressure of water arising from Gravity tends every way with equal force & is propagated as readily & with as much force sideways as downwards & through crooked passages as through streight ones. The waves on the surface of stagnating water, passing by the sides of a broad obstacle which stops part of them, bend afterwards & dilate themselves gradually into the quiet water behind the obstacle. The waves, pulses or vibrations of the Aer wherein sounds consist, bend manifestly tho not so much as the waves of water. For a Bell or a Canon may be heard beyond a hill which intercepts the sight of the sounding body, & sounds are propagated as readily through crooked pipes as through streight ones. But light is never known to follow crooked passages nor to bend into the shadow. For the fixt stars by the interposition of any of the Planets cease to be seen. And so do the parts of the Sun by the interposition of the Moon, Mercury or Venus. The rays which pass very neare to the edges of any body are bent a little by the action of the body, as we shewed above, but this bending is not towards but from the shadow, & is performed only in the passage of the ray by the body & at a very small distance from it. So soon as the ray is past the body, it goes right on.
To explain the unusual refraction of Island Crystal by pression or motion propagated has not hitherto been attempted (to my knowledge) except by Huygens who for that end supposed two several vibrating Mediums within that Crystall. But when he tryed the refractions in two successive pieces of that crystall, & found them such as is mentioned above: he confessed himself at a loss for explaining them. For pressions or motions propagated from a shining body through an uniform Medium must be on all sides alike: whereas by those experimetsexperiments it appears that the rays of light have different properties in their different sides. He suspected that the pulses of Æther in passing through the first crystall might receive certain new modifications which might determin them to be propagated in this or that Medium within the second crystal according to the position of that crystall. Mais pour dire comment cela se fait, je n'ay rien trove jusqu' ici qui me sati fasse. C.H. de la lumiere. c. 5. p 91. But what modifications those might be he could not say, nor think of any thing satisfactory in that point. And if he had known that the unusual refraction depends not on new modifications but on the original & unchangeable dispositions of the rays, he would have found it as difficult to explain how those dispositions which he supposed to be imprest on the rays by the first crystall, could be in them before their incidence on that crystall; & in general, how all rays emitted by shining bodies, can have those dispositions in them from the beginning. To me at least this seems inexplicable if light be nothing else then pression or motion propagated through Æther. And269
And it is as difficult to explain by these Hypotheses how rays can be alternately in fits of easy reflexion & easy transmission; unless perhaps one might suppose that there are in all space two ethereal vibrating Mediums, & that the vibrations of one of them constitute light, & the vibrations of the other are swifter, & as often as they overtake the vibrations of the first, put them into those fits. But how two æthers can be diffused through all space, one of which acts upon the other & by consequence is reacted upon, without retarding shattering dispersing & confounding one anothers motions is inconceivable. And against filling the heavens with fluid Mediums unless they be exceeding rare, a great objection arises from the regular & very lasting motions of the Planets & Comets in all manner of courses through the heavens. For thence it is manifest that the heavens are voyd of all sensible resistance & by consequence of all sensible matter.
For the resisting power of fluid Mediums arises partly from the attrition of the parts of the Medium & partly from the vis inertiæ of the matter. That part of the resistance of a spherical body which arises from the attrition of the parts of the Medium is very nearely as the diameter, or, at the most, as the factum of the diameter & the velocity of the spherical body together. And that part of the resistance wchwhich arises from the vis inertiæ of the matter is as the square of that factum. & the density of the Me And by this difference the two sorts of resistance may be distinguished from one another in any Medium; & these being distinguished, it will be found that almost all the resistance of bodies of a competent magnitude moving in Aer, Water, Quicksilver, & such like fluids with a competent velocity, arises from the Vis Inertiæ of the parts of the fluid
Now that part of the resistaincge power of any Medium which arises from the tenacity friction or attrition of the parts of the Medium may be diminished by dividing the matter into smaller parts & making the parts more smooth & slipery: but that part of the resistance which arises from the vis inertiæ, is proportional to the density of the matter & cannot be diminished by dividing the matter into smaller parts nor by any other means then by decreasing the density of the Medium. And for these reasons the density of fluid Mediums is very nearely proportional to their resistance. Liquors which differ not much in density as water, spirit of wine, spirit of Turpentine, hot oyle, differ not much in resistance. Water is thirteen or fourteen times lighter then Quicksilver, & by consequence thirteen or fourteen times rarer, & its resistance is less then that of quicksilver in the same proportion or thereabouts, as I have found by experiments made with Pendulums. The open Air in which we breath is eight or nine hundred times lighter then water & by consequence eight or nine hundred times rarer, & accordingly its resistance is less then that of water in the same proportion or thereabouts; as I have also found by experiments made with Pendulums. And in thinner Air the resistance is sitll less, & at length, by rarefying the Air, becomes insensible. For small feathers falling in the open Air meet with great resistance, but in a tall glass well emptied of Air they fall as fast as lead or gold, as I have seen tried several times. Whence the resistance seems still to decrease in proportion to the density of the fluid. For I do not find by any experiments that bodies moving in Quicksilver, Water or Air, meet with any other sensible resistance then what arises from the density & tenacity of those sensible fluids, as they would do if the pores of those fluids & all other spaces were filled with a dense & subtile fluid. Now if the resistance in a vessel well emptied of Air, was but an hundred times less then in the open Air, it would be about a million of times less then in quicksilver. But it seems to be much less in such a vessel, & still much less in the heavens at the height of three or four hundred miles from the earth or above. For Mr Boyle has shewed that Air may be rarefied above ten thousand times in vessels of glass: & the heavens are much emptier270 emptier of Air then any vacuum we can make below. For since the Air is comprest by the weight of the incumbent atmosphere, & the density of Air is proportional to the force compressing it, it follows by computation that at the height of about seven English miles from the Earth the aer is four times rarer then at the surface of the Earth, & at the height of 14 miles it is sixteen times rarer then at the surface of the earth, & at the height of 21, 28, or 35 miles it is respectively 64, 256 or 1024 times rarer or thereabouts; & at the height of 70, 140 or 210 miles it is about 1000000, 1000000000000 or 1000000000000000000 times rarer; & so on.
Heat promotes fluidity very much by diminishing the tenacity of bodies. It makes many bodies fluid which are not fluid in cold, & increases the fluidity of tenacious liquids as of oOyle Balsam & Honey, & thereby decreases their resistance. But it decreases not the resistance of water considerably as it would do if any considerable part of the resistance of water arose from the attrition or tenacity of its parts. And therefore the resistance of water arises principally & almost entirely from the Vis inertiæ of its matter; & by consequence, if the heavens were as dense as quicksilver they would water they would not have much less resistance then water; if as dense as quicksilver they would not have much less resistance then quicksilver; if absolutely dense or full of matter without any vacuum, let the matter be never so subtile & fluid, they would have a greater resistance then quicksilver. A solid globe in such a Medium would lose above half its motion in moving three times the length of its diameter, & a globe not solid (such as are the Planets) would be retarded sooner. And therefore to make any way for the regular & lasting motions of the Planets & Comets, its necessary to empty the heavens of all matter, except perhaps some very thin vapors steams or effluvia arising from the Atmospheres of the Earth, Planets & Comets, & such an exceedingly rare æthereal Medium as we described above. A dense fluid can be of no use for explaining the Phænomena of nature, the motions of the Planets & Comets being better explained without it. It serves only to disturb & retard the motions of those great bodies & make the frame of nature languish: & in the pores of bodies, it serves only stop the vibrating motions of their parts wherein their heat & activity consists. And as it is of no use & hinders the operations of nature & makes her languish, so there is no evidence for its existence, & therefore it ought to be rejected. And if it be rejected, the Hypotheses that light consists in pression or motion propagated through such a Medium, are rejected with it.
And for rejecting such a Medium we have the authority of those the oldest & most celebrated Philosophers of Greece & Phenicia who made a Vacuum & Atoms & the gravity of Atoms the first Principles of their Philosophy; tacitely attributing gravity to some other cause then dense matter. Later Philosophers banish the consideration of such a cause out of Natural Philosophy, feigning Hypotheses for explaining all things mechanically & referring other causes to Metaphysicks: whereas the main business of natural Philosophy is to argue from Phænomena without feigning Hypotheses, & to deduce causes from effects till we come to the very first cause, wchwhich certainly is not mechanical; & not only to unfold the mechanism of the world but chiefly to resolve these & such like questions. What is there in places almost empty of matter, & whence is it that the Sun & Planets gravitate towards one another without dense matter between them? Whence is it that Nature doth nothing in vain, & whence arises all that order & beauty wchwhich we see in the world? To what end are Comets, & whence is it that Planets move all one & the same way in Orbs concentric, while Comets move all manner of ways in Orbs very excentric, & what hinders the fixt stars from falling upon one another? How came the bodies of animals to be contrived with so much art, & for what ends were there several parts? Was the eye contrived without skill in Opticks, & the ear without knowledge of sounds? How do the motions of the body follow from the will, & whence271 whence is the instinct in animals? Is not the sensory of animals that place to wchwhich the things sensitive substance is present, & into which the sensible species of things are carried through the nerves & brain that there they may be perceived by their immediate presence to that substance? And these things being rightly dispatcht, does it not appear from phænomena that there is a Being incorporeal, living, intelligent, omnipresent, who in infinite space, as it were in his sensory, sees the things themselves intimately, & throughly perceives them & comprehends them wholy by their immediate presence to himself: of which things the images only carried through the organs of sense into our little sensoriums, are there seen & beheld by that wchwhich in us perceives & thinks. And tho every true step made in this Philosophy brings us not immediately to the knowledge of the first cause, yet it brings us nearer to it, & on that account is to be highly valued.
Qu. 29. Are not the rays of light very small bodies emitted from shining substances? For such bodies will pass through uniform mediums in right lines without bending into the shadow, wchwhich is the nature of the rays of light. They will also be capable of several properties & be able to conserve their properties unchanged in passing through several Mediums, which is another condition of the rays of light. Pellucid substances act upon the rays of light at a distance in refracting reflecting & inflecting them, & the rays mutually agitate the parts of those substance for heating them at a distance for heating them; & this action & reaction at a distance very much resembles an attractive force between bodies. if refraction be performed by attraction of the rays, the sines of incidence must be to the sines of refraction in a given proportion, as we shewed in our Principles of Philosophy; & this Rule is true by experience. The rays of light in going out of glass into a Vacuum, are bent towards the glass, & if they fall too obliquely on the vacuum they are bent backwards into the glass & totaly reflected; & this reflexion cannot be ascribed to the resistance of an absolute Vacuum, but must be caused by the power of the glass attracting the rays at their going out of it into the Vacuum & bringing them back. For if ther further surface of the glass be moistened with water or clear oyle or liquid & clear honey: the rays which would otherwise be go into the reflected will go into the water olyle or honey, & therefore are not reflected before they arrive at the further surface of the glass & begin to go out of it. If they go out of it into the water oyle or honey, they go on, because the attraction of the glass is almost ballanced & rendred ineffectual by the contrary attraction of the liquor. But if they go out of it into a Vacuum which has no attraction to ballance that of the glass, the attraction of the glass either either bends & refracts them, or brings them back & reflects them. And this is still more evident by laying together two Prisms of glass, or two Object-glasses of very long Telescopes, the one plane the other a little convex, & so compressing them that they do not fully touch nor are too far asunder. For the light which falls upon the further surface of the first glass where the interval between the glasses is not above the ten [hundred thousandth part of an inch, will go through that surface, & through the air or vacuum between the glasses, & enter into the second glass, as was explained in the first fourth & eighth Observations of the first Part of the second Book. But if the second glass be taken away, the light which goes out of the second surface of the first glass into the Air or Vacuum, will not go on forwards but turns back into the first glass & is reflected; & therefore it is drawn back by the power of the first glass, there being nothing else to turn it back. Nothing more is requisite for the producing all the variety of colours & degrees of refrangibility then that the rays of light be bodies of different sizes, the least of which may make violet the weakest & darkest of the colours, & be more272 more easily diverted by refracting surfaces from the right course; & the rest as they are bigger & bigger, may make the stronger & more lucid colours, blue, green, yellow, & red, & be more & more difficultly diverted. Nothing more is requisite for putting the rays of light into fits of easy reflexion & easy transmission, then that they be small bodies which by their attractive powers or some other force, stir up vibrations in what they act upon, which vibrations being swifter then the rays, overtake them successively, & agitate them so as by turns to increase & decrease their velocities & thereby put them into those fits. And lastly the unusual refraction of Island Crystal looks very much as if it were performed by some kind of attractive vertue lodged in certain sides both of the rays & of the particles of the crystal. For were it not for some kind of disposition or vertue lodged in some sides of the particles of the crystall & not in their other sides, & wchwhich inclines & bends the rays towards the coast of unusual refraction; the rays which fall perpendicularly on the crystall, would not be refracted towards that coast rather then towards any other coast, both at their incidence & at their emergence, so as to emerge perpendicularly by a contrary situation of the coast of unusual refraction at the second surface; the crystall acting upon the rays after they have past through it & are emerging into the Aeir, or, if you please, into a Vacuum. And since the crystall by this disposition or vertue does not act upon the rays unless when one of their sides of unusual refraction looks towards that coast, this argues a vertue or disposition in those sides of the rays, which answers to & sympathizes with that vertue or disposition of the crystall as the poles of two magnets answer to one another. And as magnetism may be intended & remitted, & is found only in the Magnet & in iron: so this vertue of refracting the perpendicular rays is greater in Island Crystall, less in Crystall of the rock, & is not yet found in other bodies. I do not say that this vertue is magnetical. It seems to be of another kind. I only say that what ever it bee, it's difficult to conceive how the rays of light unless they be bodies, can have a permanent vertue in two of their sides wchwhich is not in their other sides, & this without any regard to their position to the space or Medium through which they pass.
What I mean in this Question by a Vacuum & by the attractions of the rays of light towards glass or crystall may be understood by what was said in the 18th 19th & 20th Questions.
Qu. 30. Are not gross bodies & light convertible into one another, & may not bodies receive much of their activity from light the particles of light which enter their composition? For all fixt bodies being heated emit light so long as they continue sufficiently hot, & light mutually stops in bodies as often as its rays strike upon their parts, as we shewed above. I know no body less apt to shine then water; & yet water by frequent destillations changes into fixed earth, as Mr Boyle has tried, & then this earth being enabled to endure a sufficient heat, shines by heat like other bodies.
The changing of bodies into light & light into bodies is very conformable to the course of nature, which seems delighted with transmutations. Water wchwhich is a very fluid volatile tastless salt, she changes by heat into vapour wchwhich is a sort of air, & by cold into ice wchwhich is a hard pellucid brittle fusible stone: & this stone returns into water by heat & vapour returns into earth by water by cold. Earth by heat becomes fire & by cold returns into earth. Dense bodies by fermentation rarefy into several sorts of air, & this air by fermentation & sometimes without it; returns into dense [bodies. Mercury appears sometimes in the form of a fluid metall, sometimes in the form of a hard brittle metall; sometimes in the form of a corrosive pellucid salt called sublimate, sometimes in the form of a tastless pellucid volatile white earth called Mercurius273 Mercurius dulcis, or in that of a red opake volatile earth called Cinnaber, or in that of a red or white Precipitate, or in that of a fluid salt; & in destillation it turns into vapour, & beign agitated in Vacuo it shines like fire. And after all these changes it returns again into its first form of Mercury. Eggs grow from insensible magnitudes & change into animals, Tadpoles into Froggs, & Worms into flyes. All Birds Beasts & Fishes, Insects Trees & other Vegetables with their several parts, grow out of water & watry substances tinctures & salts, & by putrefaction return again into watry substances. And water standing a few days in the open air, yeilds a tincture, which (like that of Mault) by standing longer yeilds a sediment & a spirit, but before putrefaction is fit nourishment for animals & vegetables. And among such various & strange transmutations, why may not nature change bodies into light & light into bodies?
Qu. 31. Have not the small particles of bodies certain powers virtues or forces by which they act at a distance, not only upon the rays of light for reflecting refracting & inflecting them, but also upon one another for producing a great part of the phænomena of nature? For its well known that bodies act one upon another by the attractions of gravity one among another magnetism & electricity, & these instances shew the tenour & course of nature, & make it not improbable that but that there may be more attractive powers then these. For Nature is very consonant & conformable to her self. How these attractions may be performed I do not here consider. What I call attraction may be performed by impulse or by some other means unknown to me. I use that word here to signify only in general any force by which bodies tend towards one another whatsoever be the cause. For we must learn from the phænomena of nature what bodies attract one another, & what are the laws & properties of the attraction, before we enquire the cause by which the attraction is performed. The attractions of gravity magnetism & electricity reach to very sensible distances, & so have been observed by vulgar eyes, & there may be others which reach to so small distances as hitherto escape observation, & perhaps electrical attraction may reach to such small distances even without being excited by friction.
For when salt of Tartar runs per deliquium, is not this done by an attraction between the particles of the salt of Tartar & the particles of the water which float in the Aer in the form of vapors? And why does not common salt or saltpeter or vitriol run per deliquium but for want of such an attraction? Or why does not salt of Tartar draw more water out of the Air then in a certain proportion to its quantity, but for want of an attractive force after it is satisfiedtiated with water? And whence is it but from this attractive power that water wchwhich alone distills with a gentle heat lukewarm heat will not destill from salt of Tartar but from without a great heat? And is it not from the like attractive power between the particles of oyle of Vitriol & the particles of water, that Oyle of Vitriol draws to it a good quantity of water out of the Air, & after it is satiated draws no more, & in destillations lets go the water very difficultly? And when water & oyle of Vitriol poured sucessively into the same vessel grow very hot in the mixing, does not this heat argue a great motion in the parts of the liquors? And does not this motion argue that the parts of the liquo two liquors in mixing coaless with violence & by consequence rush towards one another with an accelerated motion? And when Aqua fortis or spirit of Vitriol poured upon filings of iron dissolves the filings with a great heat & ebullition, is not this heat & ebullition effected by a violent motion of the274 the parts, & does not that motion argue that the acid parts of the liquor rush towards the parts of the metall with violence, & run forcibly into its pores till they get between its outmost particles & the main mass of the metall, & surrounding those particles loosen them from the main mass & set them at liberty to flote off into the water? And when the acid particles which alone would destill with an easy heat will not separate from the particles of the metall without a very vio[lent heat, does not this confirm the attraction between them?
When spirit of Vitriol poured upon common salt or saltpeter makes an ebullition with the salt & unites with it, & in destillation the spirit of the common salt or saltpeter comes over much esiereasier then it would do before, & the acid part of the spirit of Vitriol stays behind; does not this argue that the fixed Alcaly of the salt attracts the acid spirit of the Vitriol more strongly then its own spirit, & not being able to hold them both, lets go its own? And when oyle of Vitriol is drawn off from its weight of Nitre, & from both the ingredients a compound spirit of Nitre is destilled, two parts of wchwhich being poured on one part of cloves oyle of cloves or Carvy seeds, or of any ponderous vegetable oyle, or oyle of animal substances, or oyle of Turpentine thickened with a little Balsam of sulphur, grows so very hot in mixing as presently to send up a burning flame: does not this very great & sudden heat argue that the two liquors mix with violence, & that their parts in mixing run towards one another with an accelerated motion, & clash with the greatest force? And is it not for the same reason that well rectified spirit of wine poured on the same compound spirit flashes, & that the pulvis fulminans composed of sulphur Nitre & salt of Tartar, goes off with a more sudden & violent explosion then Gun-powder, the acid spirits of the sulphur & nitre rushing towards one another & towards the Tartar salt of Tartar with so great a violence, as by the shock to turn the whole at once into vapour & flame? Where the dissolution is slow it makes a slow ebullition & a gentle heat, & where it is quicker it makes a greater ebullition with more heat, & where it is done at once the ebullition is contracted into a sudden blast or violent explosion with a heat equal to that of fire & flame. So when a drachm of the above-mentioned compound spirit of Nitre was poured upon half a drachm of oyle of Carvi sees in vacuo, the mixture immediately made a flash like gunpowder & burst the exhausted Receiver, which was a glass six inches wide and eight inches deep. And even the gross body of sulphur poudered, & with an equal weight of iron filings & a little water made into past, acts upon the iron, & in five or six hours grows too hot to be touched, & emits a flame. And by these experiments compared with the great quantity of Sulphur with which the Earth abounds, & the warmth of the interior parts of the earth & hot springs & burning mountains & with damps, mineral corruscations, earthquakes, hot suffocating exhalations, hurricanes & spouts: we may learn that sulphureous steams abound in the bowells of the earth & ferment with mineralls, & sometimes take fire with a sudden corruscation & explosion, & if pent up in subterraneous caverns, burst the caverns with a great shaking of the earth as in springing of a Mine. And then the vapour generated by the explosion, expiring through the pores of the earth, feels hot & suffocates & makes tempests & hurricanes, & sometimes causes the land to slide, or the sea to boyle, & carries up the water thereof in drops which by their weight fall down again in spouts. Also some sulphureous steams, at all times when the earth is dry, ascending into the Air, ferment there with nitrous acids, & sometimes taking fire cause lightning & thunder & fiery meteors. For the Air abounds with acid vapours fit to275 to promote fermentations, as appears by the rusting of iron and copper in it, the kindling of fire by blowing, & the beating of the heart by means of respiration. Now the above mentioned motions are so great & violent as to shew that in fermentations, the particles of bodies which almost rest are put into new motions by a very potent principle which acts upon them only when they approach one another, & causes them to meet & clash with great violence, & grow hot with the motion, & dash one another into pieces, & vanish into air & vapour & flame.
When salt of Tartar per deliquium, being poured into the solution of any metal, precipitates the metall, & makes it fall down to the bottom of the liquor in the form of mud: does not this argue that the acid particles are attracted more strongly by the salt of Tartar then by the metall, & by the stronger attraction go from the metal to the salt of Tartar? And so when a solution of iron in Aqua fortis dissolves the Lapis Calaminaris & lets go the iron, or a solution of Copper dissolves iron immersed in it & lets go the copper, or a solution of silver dissolves copper & lets go the silver, or a solution of Mercury in Aqua fortis being poured upon Iron Copper Tin or Lead, dissolves the metall & lets go the Mercury, does not this argue that the acid particles of the Aqua fortis are attracted more strongly by the Lapis Calaminaris then by Iron, & more strongly by iron then by copper, & more strongly by Copper then by silver, & more strongly by Iron Copper Tin & Lead then by Mercury? And is it not for the same reason that iron requires more Aqua fortis to dissolve it then Copper, & Copper more then the other metalls; & that of all metalls, Iron is dissolved most easily, & is most apt to rust; & next after Iron, Copper?
When Oyle of Vitriol is mixed with a little water, or is run per deliquium, & in destillation the water ascends difficultly, & brings over with it some part of the oyle of Vitriol in the form of spirit of Vitriol, & this spirit upon being poured upon iron copper or salt of Tartar unites with the body & lets go the spirit water, doth not this shew that the acid spirit is attracted by the water, & more attracted by the fixt body then by the water, & therefore lets go the water to close with the fixt body? And is it not for the same reason that the water & acid spirits which are mixed together in Vinegar, Aqua fortis, & spirit of salt, cohere & rise together in destillation; but if the Menstruum be poured on salt of Tartar, or on Lead or Iron or any fixt body which it can dissolve, the acid by a stronger attraction adheres to the body & lets go the water? And is it not also from a mutual attraction that the spirits of soot & sea-salt unite & compose the particles of Salarmoniac, wchwhich are less volatile then before because grosser & freer from water; & that the particles of Salarmoniac in sublimation carry up the particles of Antimony wchwhich will not sublime alone; & that the particles of Mercury uniting with the acid particles of spirit of salt compose Mercury sublimate, & with the particles of Sulphur compose cinnaber; & that the particles of spirit of wine & spirit of urin well rectified unite, & letting go the water which dissolved them compose a consistent body; & that in subliming cinnaber from salt of Tartar or from quick lime, the sulphur by a stronger attraction of the salt or lime lets go the Mercury & stays with the fixt body; & that when Mercury sublimate is sublimed from Antimony or from Regulus of Antimony, the spirit of salt lets go the Mercury, & unites with the Antimonial metall which attracts it more strongly, & stays with it till the heat be great enough to make them both ascend together, & then carries up the metall with it in the form of a very fusible salt called Butter of Antimony, although the spirit of salt alone be almost as volatile as water, & the Antimony alone as fixt as Lead? When276
When Aqua fortis dissolves silver & not gold, & Aqua regia dissolves gold & not silver; may it not be said that Aqua fortis is subtile enough to penetrate gold as well as silver, but wants the attractive force to give it entrance, & that Aqua regia is subtile enough to penetrate silver as well as gold, but wants the attractive force to give it entrance? For Aqua regia is nothing else then Aqua fortis mixed with some spirit of salt or with Salarmoniac; & even common salt dissolved in Aqua fortis enables the Menstruum to dissolve gold tho the salt be a gross body. When therefore spirit of salt precipitates silver out of Aqua fortis, is it not done by attracting & mixing with the Aqua fortis, & not attracting or perhaps repelling silver? And when water precipitates Antimony out of the sublimate of Antimony & Salarmoniac, or out of butter of Antimony, is it not done by its dissolving, mixing with & weakening the Salarmoniac or spirit of salt & its not attracting or perhaps repelling the Antimony? And is it not for want of an attractive vertue between the parts of water & oyle, of Quicksilver & Antimony, of Lead & Iron, that these substances do not mix; and by a weak attraction that Quicksilver & Copper mix difficultly; & from a strong one that Quicksilver & Tin, Antimony & Iron, water & salts mix readily? And in general, is it not from the same principle that heat congregates homogeneal bodies & separates heterogeneal ones?
When Arsnick with soap gives a Regulus & with Mercury sublimate a volatile fusible salt like butter of Antimony; doth not this shew that Arsnick, wchwhich is a substance totally volatile, is compounded of fixt & volatile parts strongly cohereingcohering by a mutual attraction so that the volatile will not ascend without carrying up the fixed? And so, when an equal weight of spirit of wine & oyle of vitriol are digested together, & in destillation yeild two fragrant volatile spirits wchwhich will not mix with one another, & a fixt black earth remains behind; doth not this shew that oyle of Vitriol is composed of volatile & fixed parts strongly united by attraction so as to ascend together in form of a volatile acid fluid salt, untill the spirit of wine attracts & separates the volatile parts from the fixed? And therefore since oyle of sulphur per campanam is of the same nature with oyle of Vitriol; may it not be inferred that Sulphur is also a mixture of volatile & fixed parts so strongly cohering by attraction as to ascend together in sublimation. By dissolving flowers of sulphur in oyle of Turpentine & diestilling the solution, it is found that Sulphur is composed of an inflamable thick oyle or fat bitumen, an acid salt, a very fixed earth & a little sulphur metall. The three first were found not much unequall to one another, the fourth in so small a quantity as scarce to be worth considering. The acid salt dissolved in water is the same with Oyle of Sulphur per Campanam, & abounding much in the bowells of the earth & particularly in Markasites, unites it self to the other ingredients of the Markasite, which are, Bitumen, Iron, Copper & Earth, & with them compounds Alume, Vitriol, & Sulphur. With the earth alone it compounds Alume; with the Metall alone or Metal & Sal earth together it compounds Vitriol; & with the Bitumen & Earth it compounds Sulphur. Whence it comes to pass that Marcasites abound with those three Mineralls. And is it not from the mutual attraction of the ingredients that they stick together for compounding these mineralls, & that the Bitumen carries up the other ingredients of the sulphur, which without it would not sublime? And the same Question may be put concerning all or almost all the gross bodies in nature. For all the parts of animals & vegetables are composed of substances volatile & fixed, fluid & solid, as appears by their Analysis; & so are salts & minerals so far as Chymists have been hitherto able to examin their composition. When277
When Mercury sublimate is resublimed with fresh Mercury & becomes Mercurius dulcis, which is a white tastless earth scarce dissolvable in water, and Mercurius dulcis resublimed with spirit of salt returns into Mercury sublimate; & when Metalls corroded with a little acid turn into rust, which is an earth tastless & indissolvable in water, & this earth imbibed with more acid becomes a metallic salt; & when some stones, as Spar of Lead, dissolved in proper menstruums become salts; do not these things shew that salts are dry earth, & watry acid united by attraction, & that the earth will not become a salt without so much acid as makes it dissolvable in water? Do not the sharp & pungent tasts of acids arise from the strong attraction whereby the acid particles rush upon & get agitate the particles of the tongue? And when metalls are dissolved in acid menstruums, & the acids in conjunction with the metall act after a different manner so that the compound has a different tast much milder then before, & sometimes a sweet one; is it not because the acids adhere to the metallic particles, & thereby, lose much of their activity? And if the acid be in too small a proportion to make the compound dissolvable in water, will it not by adhering strongly to the metall become unactive & lose its tast, & the compound be a tastless earth? For such things as are not dissolvable by the moisture of the tongue, act not upon the tast.
As gravity makes the sea flow round the denser & weightier parts of the globe of the earth; so the attraction may make the watry acid flow round the denser & compacter particles of earth for composing the particles of salt. For otherwise the acid would not do the office of a medium between the earth & common water for making salts dissolvable in the water: nor would salt of Tartar readily draw off the acid from dissolved metalls; nor metalls the acid from Mercury. Now as in the great globe of the earth & sea, the densest bodies by their gravity sink down in water, & always endeavour to go towards the center of the globe; so in particles of salt the densest matter may always endeavour to approach the center of the particle: so that a particle of salt may be compared to a chaos, being dense hard dry & earthy in the centre, & rare, soft, moist, & watry in the circumference. And hence it seems to be that salts are of a lasting nature, being scarce destroyed unless by drawing away their watry parts by violence or by violence or by letting them soak into pthe pores of the central earth by a gentle heat in putrefaction, untill the earth be dissolved by the water, & separated into smaller particles, which by reason of their smallness make the rotten compound appear of a black colour. Hence also it may be that the parts of animals & vegetables preserve their several forms & assimilate their nourishment; the soft & moist nourishment easily changing its texture by a gentle heat & moisture motion, till it becomes like the dense hard dry & durable earth in the centre of each particle. But when the nourishment grows unfit to be assimilated, or the central earth grows too feeble to assimilate it, the motion ends in putrefaction confusion, putrefaction, & death.
If a very small quantity of any salt or Vitriol be dissolved in a great quantity of water, the particles of the salt or vitriol will not sink to the bottom, tho they be heavier in specie then the water, but will eavenly diffuse themselves into all the water, so as to make it as saline at the top as at the bottom. And does not this imply that the parts of the salt or Vitriol recede from one another, & endeavour to expand themselves, & get as far asunder as the quantity of water in which they float, will allow? And278
And does not this endeavour imply that they have a repulsive force by which they fly from one another, or at least that they attract the water more strongly then they do one another? For as all things ascend in water which are less attracted then water by the gravitating power of the earth: so all the particles of salt which float in water & are less attracted then water by any one particle of salt, must recede from that particle & give way to the more attracted water.
When any saline liquor is evaporated to a cuticle & let cool, the salt concretes in regular figures, which argues that the particles of the salt before they concreted, floated in the liquor at equal distances in rank & file, & by consequence that they acted upon one another by some power which at equal distances is equal, at unequal distances unequal. For by such a power they will range themselves uniformly, & without it they will float irregularly & come together as irregularly. And since the particles of Island Crystall act all the same way upon the rays of light for causing the unusual refraction, may it not be supposed that in the formation of this crystall, the particles not only ranged themselves in rank & file for concreting in regular figures, but also by some kind of polar vertue turned their homogeneal sides the same way.
The parts of all homogeneal hard bodies which fully touch one another stick together very strongly. And for explaining how this may be some have invented hooked atoms, which is begging the question; & others tell us that bodies are glued together by rest, that is, by an oOccult Quality, or rather by nothing; & others that they stick together by conspiring motions, that is, by relative rest amongst themselves. I had rather inferr from their cohesion, that their particles attract one another by some force, which in immediate contact is exceeding strong, at small distances performs the chymical operations above mentioned, & reaches not far from the particles with any sensible effect.
All bodies seem to be composed of hard particles: For otherwise fluids would not congeale, as water, oyles, vinegre, & spirit or oyle of Vitriol do by freezing, Mercury by fumes of Lead, spirit of Nitre & Mercury by dissolving the Mercury & evaporating the flegm, spirit of Wine & spirit of Urin by deflegming & mixing them, & spirit of urine & spirit of salt by subliming them together to make Salarmoniac. Even the rays of light seem to be hard bodies: for otherwise they would not retain different properties in their different sides. And therefore hardness may be recconed the property of all uncompounded matter. At least this seems to be as evident as the universal impenetrability of matter. For all bodies so far as experience reaches, are either hard or may be hardned, & we have no other evidence of universal impenetrability besides a large experience without an experimental exception. Now if compound bodies are so very hard as we find some of them to be, & yet are very porous, & consist of parts which are only laid together: the simple particles which are void of pores & were never yet divided, must be much harder. For such hard particles being heaped up together, can scarce touch one another in more then a few points, & therefore must be separable by much less force then is requisite to break a solid particle, whose parts touch in all the space between them without any pores or interstices to weaken their cohesion. And how such very hard particles which are only laid together & touch only in a few points, can stick together, & that so firmly as they do, without the assistance of something which causes them to be attracted or prest towards one another, is very difficult to conceive.
The same thing I inferr also from the cohering of two polished Marbles in Vacuo, & from the standing of Quicksilver in the Barometer at the height of279 of 50, 60 or 70 inches or above, when ever it is well purged of air & carefully poured in, so that its parts be every where contiguous, both to one another & to the glass. The Atmosphere by its weight presses the Quicksilver ‡ ‡ into the glass to the height of 29 or 30 inches. And some other Agent raises it higher, not by pressing it into the glass but by making its parts stick to the glass & to one another. For upon any discontinuation of parts made either by bubbles or by shaking the glass, the whole Mercury falls down to the height of 29 or 30 inches.
And of the same kind with these experiments are those that follow. If two plane polished plates of glass (suppose two pieces of a polished looking-glass) be laid together so that their sides be parallel & at a very small distance from one another, & then their lower edges be dipped into water; the water will rise up between them. And the less the distance of the glasses is, the greater will be the height to which the water will rise. If the distance be about the hundredth part of an inch, the water will rise to the height of about an inch; & if the distance be greater or less in any proportion, the height will be reciprocally proportional to the distance very nearly. For the attractive force of the glasses is the same whether the distance between them be greater or less; & the weight of the water drawn up, is the same, if the height, of it be reciprocally proportional to the height distance of the glasses. And in like manner, water ascends between two Marbles polished plane, when their polished sides are parallel, & at a very little distance from one another. And if slender pipes of glass be dipped at one end into stagnating water, the water will rise up within the pipe, & the height to which it rises will be reciprocally proportional to the diameter of the pipe cavity of the pipe, & will equal the height to which it rises between two planes of glass, if the semidiameter of the cavity of the Pipe be equal to the distance between the planes, or thereabouts. And these Experiments succeed after the same manner in Vacuo as in the open Aer, & therefore are not influenced by the weight or pressure of the Atmosphere.
And if a large Pipe of glass be filled with sifted ashes well pressed together in the glass, & one end of the Pipe be dipped into stagnating water: the water water will rise up slowly in the ashes so as in the space of a week or fortnight to reach up within the glass to the height of 30 or 40 inches above the stagnating water. And the water rises up to this height by the attraction only of those particles of the ashes only which are upon the surface of the elevated water; the particles wchwhich are within the water, attracting it as much downwards as upwards. And therefore the attraction of the particles is very strong. But the particles of the ashes being not so dense & close together as those of glass their attraction is not so strong as that of glass wchwhich keeps Quicksilver suspended to the height of 60 or 70 inches & therefore attracts with a force wchwhich would keep water suspended to the height of above fifty feet.
By the same principle, a Sponge sucks in water, & the Glands in the bodies of animals, according to their several natures & dispositions, suck in various juices from the blood.
If two plane polished plates of glass three or four inches broad & twenty or twenty five long, be laid, one of them parallel to yethe horizon, the other upon the first so as at one of their ends to touch & one another & contein an Angle of about 10 or 15 minutes, & the same be first moistened on their inward sides with a clear cloth dipt into oyle of Oranges or spirit of Turpentine, & a drop or two of the Oyle or Spirit be let fall upon the lower glass at the other end: so soon as the upper glass is laid down upon the lower so as to touch it at one end as above, & to touch the drop at the other end, making with the lower glass an angle of about 10 or 15 minutes; the drop will begin to move towards the concourse of the glasses, & will continue to move with an accelerated280 accelerated motion till it arrives at that concourse of the glasses. For the two glasses attract the drop & make it run that way towards which the attractions incline. And if when the drop is in motion you lift up that end of the glasses where they meet & towards which the drop moves: the drop will ascend between the glasses & therefore is attracted. And as you lift up the glasses more & more the drop will ascend slower & slower & at length rest being then carried downward by its weight as much as upwards by the attraction. And by this means you may know the force by which the drop is attracted at all distances from the concourse of the glasses.
Now by some experiments of this kind it has been found that the attraction is almost reciprocally in a duplicate proportion of the distance of the middle of the drop from the concourse of the glasses; [viz, reciprocally in a [simple proportion by reason of the spreading of the drop & its touching each glass in a larger surface; & again reciprocally in a simple proportion by reason of the spreading of the drop attractions growing stronger within the same quantity of attracting surface. The attraction therefore within the same quantity of attracting surface, is reciprocally as the distance between the glasses. And therefore where the distance is exceeding small, the attraction must be exceeding great. By the Table in the second part of the second Book, wherein the thicknesses of coloured plates of water between two glasses are set down, the thickness of the Plate where it appears very black, is three eighths of the ten hundred thousandth part of an inch. And where the oyle of Oranges between the glasses is of this thickness, the attraction collected by the foregoing Rule, seems to be so strong, as within a circle of an inch in diameter to suffice to hold up a weight equal to that of a cylinder of water of an inch in diameter & two or three furlongs in length. And where it is of a less thickness the attraction may be proportionally greater, & continue to increase untill the thickness do not exceed that of a single particle of the Oyle. There are therefore Agents in nature able to make the particles of bodies stick together by very strong attractions. And it is the buisinessbusiness of experimental Philosophy to find them out.
Now the smallest particles of matter may cohere by the strongest attractions & compose bigger particles of weaker vertue, & many of these may cohere & compose bigger particles whose vertue is still weaker, & so on for divers successions untill the progression end in the biggest particles on which the operations in Chymistry & the colours of natural bodies depend & which by cohering compose bodies of a sensible magnitude. If the body is compact & bends or yeilds inward to pression without any sliding of its parts, it is hard & elastick, returingreturning to its figure with a force arising from the mutual attraction of its parts. If the parts slide upon one another the body is malleable or soft. If they slip easily & are of a fit size to be agitated by heat, & the heat is big enough to keep them in agitation the body is fluid; & if it be apt to stick to things it is humid; & the drops of every fluid affect a round figure by the mutual attraction of their parts, as the globe of the Earth & Sea affects a round figure th by the mutuall attraction of its parts by gravity.
Since metalls dissolved in acids attract but a small quantity of the acid, their attractive force can reach but to a small distance from them. And as in Algebra, where affirmative quantities vanish & cease, there negative ones begin, so in Mechanicks, where attraction ceases there a repulsive vertue ought to succeed. And that there is such a vertue seems to follow from the reflexions & inflexions of the rays of light. For the rays are repelled by bodies in both these cases without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of light, the ray so soon as it is shaken off from a shining body by the vibrating motion of the parts of the body, & gets beyond the reach of attraction, being driven away with exceeding great velocity. For that force281 force which is sufficient to turn it back in reflexion may be sufficient to emit it. It seems also to follow from the production of Air & Vapor. The particles when they are shaken off from bodies by heat or fermentation, so soon as they are beyond the reach of the attraction of the body, receding from it, & also from one another with great strength, & keeping at a distance, so as sometimes to take up above a million of times more space then they did before in the form of a dense body. Which vast contraction & expansion seems unintelligible by feigning the particles of Air to be spongy springy & ramous, or rolled up like hoops, or by any other means then a repulsive power. The particles of fluids which do not cohere too strongly & are of such a smallness as renders them most susceptible of those agitations wchwhich keep liquors in a fluor, are most easily separated & rarefied into vapor, & in the language of the Chymists, they are volatile, rarefying with an easy heat & condensing with cold. But those which are grosser & so less susceptible of agitation or cohere by a stronger attraction, are not separated without a stronger heat, or perhaps, not without fermentation. And these last are the bodies wchwhich Chemists call fixed, & being rarefied by fermentation become true permanent air: those particles receding from one another with the greatest force, & being most difficultly brought together, wchwhich upon contact cohere most strongly. And because the particles of permanent Air are grosser & arise from substances denser substances then those of vapors, thence it is that true Air is more ponderous then vapor, & that a moist atmosphere is lighter then a dry one quantity for quantity. From the same repelling power it seems to be that flyes walk upon the water without wetting their feet; & that the Object-glasses of long Telescopes lye upon one another without touching; & that dry pouders are difficultly made to touch one another so as to stick together, unless by melting them, or wetting them with water which by exhaling may bring them together; & that two polished marbles which by immediate contact stick together, are difficultly brought together so close together as to stick.
And thus Nature will be very conformable to her self & very simple, performing all the great motions of the heavenly bodies by the attraction of gravity wchwhich intercedes those bodies, & almost all the small ones of their particles by some other attractive & repelling powers wchwhich interceede the particles. The Vis inertiæ is a passive principle by wchwhich bodies persist in their motion or rest, receive motion in proportion to the force impressing it, & resist as much as they are resisted. By this Principle alone there never could have been any motion in the world. Some other Principle was necessary for putting bodies into motion; & now they are in motion some other Principle is necessary for conserving the motion. For from the various composition of two motions tis very certain that there is not always the same quantity of motion in the world. For if two globes joyned by a slender rod, revolve about their common center of gravity with an uniform motion while that center moves on uniformly in a right line drawn in the plane of their circular motion; the summ of the motions of the two globes, as often as the globes are in the right line described by their common center of gravity, will be bigger then the summ of their motions when they are in a line perpendicular to that right line. By this instance it appears that motion may be got or lost. But by reason of the tenacity of fluids, & attrition of their parts, & the weakness of elasticity in solids, motion is much more apt to be got t lost then got, & is always upon the decay. For bodies which are either absolutely hard, or so soft as to be void of elasticity, will not rebound from one another. Impenetrability makes them only stop. If two equal bodies meet directly in Vacuo they282 they will by the laws of motion stop where they meet & lose all their motion & remain in rest unless they be elastick & receive new motion from their spring. If they have so much elasticity as suffices to make them rebound with a quarter or half or three quarters of the force with which they come together, they will lose three quarters or half or a quarter of their motion. And this may be tried by letting two equal Pendulums fall against one another from equal heights. If the Pendulums be of lead or soft clay they will lose all or almost all their motions: if of elastick bodies they will lose all but what they recover from their elasticity. If it be said that they can lose no motion but what they communicate to other bodies; the consequence is that in Vacuo they can lose no motion, but when they meet they must go on & penetrate one anothers dimensions. If three equal round Vessels be filled the one with water, the other with oyle, the third with molten pitch, & the liquors be stirred about alike to give them a vortical motion: the pitch by its tenacity will lose its motion quickly, the oyle being less tenacious will keep it longer, & the water being least tenacious will keep it longest, but yet will lose it in a short time. Whence it is easy to understand that if many contiguous Vortices of molten pitch were each of them as large as those which some suppose to revolve about the Sun & fixt starrs, yet these & all their parts would by their tenacity & stifness communicate their motion to one another till they all rested among themselves. Vortices of oyle or water or some fluider matter might continue longer in motion, but unless the matter were void of all tenacity & attrition of parts & communication of motion (wchwhich is not to be supposed,) the motion would constantly decay. Seing therefore the variety of motion which we see find in the world is always decreasing, there is a necessity of conserving & recruiting it by active principles, such as are the cause of gravity by which Planets & Comets keep their motions in their Orbs & bodies acquire great motion in falling; & the cause of fermentation by which the heart & blood of animals are kept in perpetual motion & heat, the inward parts of the earth are constantly warmed & in some places grow very hot, bodies burn & shine, mountains take fire, the caverns of the earth are blown up, & the Sun continues violently hot & lucid & warms all things by his light. For we meet with very little motion in the world besides what is oweing to these active Principles. And if it were not for these Principles the bodies of the Earth, Planets, Comets, Sun, & all things in them would grow cold & freeze & become inactive masses, & all putrefaction generation vegetation & life would cease, & the Planets the Planets & Comets would not remain in their Orbs.
All these things being considered, it seems to me that God in the beginning formed matter in solid massy hard impenetrable moveable particles of such sizes & figures & with such other properties & in such proportion to space as most conduced to yethe end for wchwhich he formed them, & that these primitive particles being solids are incomparably harder then any porous bodies compounded of them; even so very hard as never to wear or break in pieces: no ordinary power being able to divide what God himself made one in the first creation. While the particles continue entire they may compose bodies of one & the same nature & texture in all ages: but should they weare away, or break in pieces, the nature of things depending on them, would be changed. Water & Earth composed of old worn particles & fragments of particles would not be of the same nature & texture now with water & earth composed of entire particles in the beginning. And therefore that nature may be lasting, the changes of corporeal things are to be placed only in the various separations & new associations & motions of these permanent particles; compound bodies being apt to break, not in the midst of solid particles, but where those particles are laid together not & only touch in a few points. It283
It seems to me further that these particles have not only a Vis inertiæ accompanied with such passive laws of motion as naturally result from that force, but also that they are moved by certain active principles such as is that of Gravity & that which causes fermentation & the cohesion of bodies. These Principles I consider not as oOccult Qualities supposed to result from the specific forms of things, but as general laws of nature by which the things [themselves are formed: their truth appearing to us by phænomena though their causes be not yet discovered. For these are manifest qualities, & their causes only are occult. To tell us that every species of things is endowed with an occult specific quality by which it acts & produces manifest effetseffects, is to tell us nothing: but to derive two or three general Principles of motion from Phænomena, & afterwards to tell us how the properties & actions of all corporeal things follow from those manifest Principles, would be a very great step in Philosophy, tho the causes of those Principles were not yet discovered: & therefore I scruple not to propose the Principles of motion above mentioned, they being of very general extent, & leave their causes to be found out.
Now by the help of these Principles all motions material things seem to have been composed of the hard & solid Particles above mentioned variously associated in the first creation by the counsell of an intelligent Agent. For it became him who created them to set them in order. And if he did so, it's unphilosophical to seek for any other origin of the world, or to pretend that it might arise out of a Chaos by the mere laws of nature; tho being once formed it may continue by those laws for many ages. For while Comets move in very excentric Orbs in all manner of positions, blind fate could never make all the Planets move one & the same way in Orbs concentrick, some inconsiderable irregularities excepted which may have risen from the mutual actions of Comets & Planets upon one another, & wchwhich will be apt to increase till this Systeme wants a reformation. Such a wonderfull uniformity in the Planetary Systeme must be allowed the effect of choise. And so must the uniformity in the bodies of aAnimals, they having generally a right & a left side shaped alike & on either side of their bodies two leggs behind & either two arms or two leggs or two wings before upon their sholders & between their sholders a neck running down into a back bone & a head upon it, & in the head two ears, two eyes, a nose, a mouth & a tongue alike situated. Also the first contrivance of those very artificial parts of animals, the eyes, ears, brain, muscles, heart, Lungs, Midriff, Glands, Larynx, Hands, Wings, Swimming-bladders, natural Spectables, & other organs of sense & motion, & the Instinct of Brutes & Insects, can be the effect of nothing else then the wisdome & skill of a powerful ever living agent, who being in all places is more able by his Will to move the bounds of bodies within his boundless unorganized uniform Sensorium & thereby to form & reform the parts of the Universe, then we are by our will to move the parts of orour own bodies. And yet we are not to consider the world as the body of God or the parts several parts thereof as the parts of God. They He is an uniform Being void of Organs, Members, or Parts, & they are his Creatures subordinate to him & subservient to his will, & hie is no more the soul of them then the Soul of a man is the Soul of the Species of things carried through the Organs of Sense into the place of its sensation, where b it perceives them by means of its immediate presence without the intervention of any third thing. The Organs of Sense are not for enabling the soul to perceive the Species of things in its Sensorium, but only for conveying them thither, & God has no need of such Organs, he being every where present to the things themselves. And since space is divisible in infinitum & matter is not necessarily in all places, it masty be also allowed that God is able to create matter particles of matter284 matter of several sizes & figures & in several proportions to space, & perhaps of different densities & forces, & thereby to vary the Laws of Nature, & make worlds of several sorts in several parts of the Universe. At least I see nothing of contradiction in all this.
As in Mathematicks so in Natural Philosophy the investigation of difficult things by the Method of Analysis ought ever to precede the method of composition. This Analysis consists in making Experiments & observations & in drawing general conclusions from them by Induction, & admitting of no objections against the Conclusions but such as are taken from experiments or other certain truths. For Hypotheses are not to be regarded in experimental Philosophy. And altho the arguing from experiments & observations by Induction be no demonstration of general C Conclusions yet it is the best way of arguing which the nature of things admits of, & may be looked upon as so much the stronger by how much the Induction is more general And if no exception occur from Phænomena the conclusion may be pronounced generally. But if at any time afterwards any exception shall occur from experiments, it may then begin to be pronounced with such exceptions as occur. By this way of Analysis we may proceed from compositionundss to ingredients, & from motions to the forces producing them, & in general from effects to their causes, & from particular causes to more general ones, till the Argument end in the most general. This is the Method of Analysis: & the Synthesis consists in assuming the causes discovered & established as Principles, & by them explaining the Phenomena proceeding from them, & proving the explanations.
In the two first books of these Opticks, I proceeded by this Analysis to discover & prove the original differences of they rays of light in respect of refrangibility, reflexibility, & colour, & their alternate fits of easy reflexion & easy transmission, & the properties of bodies both opake & pellucid on which their reflexions & colours depend. And these discoveries being proved may be assumed in the method of Composition for explaining the Phænomena arising from them: an instance of which Method I gave in the end of the first Book. In this third Book I have only begun the Analysis of what remains to be discovered about light & its effects upon the frame of nature, hinting several things about it & leaving the hints to be examined & improved by the farther experiments & observations of such as are inquisitive. And if natural Philosophy in all its parts, by pursuing this method, shall at length be perfected, the bounds of moral Philosophy will be also enlarged. For so far as we can know by Natural Philosophy what is the first Cause, what power he has over us, & what benefits we receive from him, so far our duty towards him as well as that towards one another, will appear to us by the light of Nature. And no doubt, if the worship of fals Gods had not blinded the heathen, their moral Philosophy would have gone further then to the four cCardinal vVertues; & instead of teaching the transmigration of souls & to worship the Sun & Moon & dead Heroes, they would have taught us to worship our true Author & Benefactor. 285
All these things being considered it seems to me that God [Deus O. M.] in yethe beginning createdformed matter in solid massy hard impenetrable moveable particles of such sizes & figures & with such other properties & in such proportion to space as most conduced to the end for wchwhich he created them. And that these primitive particles being solids are incomparably harder then any porous bodies compounded of them; even so very hard as never to weare or break in pieces: no ordinary power being able to divide what God himself made one in the first creation. While these particles continue entire they may compose bodies of the same nature & texture in all ages: but should they weare away or break in pieces, the nature of things depending on them would be changed. Water & Earth composed of old worn particles & fragments of particles would not be of the same nature & texture now &with water & earth composed of entire particles in the beginning. And therefore that nature may be lasting, the changes of corporeal things are to be placed only in yethe various separations & &, new associations & motions of these permanent particles, compound bodies being apt to break not in the midst of solid particles but where those particles are laid together & only touch in a few points.
It seems to me further that these permanent particles have not only a Vis inertiæ accompanied accompanied wthwith such passive laws of motion as naturally result from that force, but also that they are endowed with accompanied moved by certain active principles of motion such as is that of Gravity & that wchwhich causes fermentation & the cohesion of bodies. These Principles I consider not as occult qQualities resulting from which supposed to are supposed to resulting from the specific forms of things but as general Laws of Nature from whence the forms by wchwhich yethe things themselves result. are formed: Their Truth appearing to us by phænomena, though their causes be ntnot ytyet explaind. To tell us that every species of things is endowed wthwith an occult specificly Quality by wchwhich it acts, is to tell us nothing; but to derive two or three general Principles of motion from Phænomena, & afterwards to tell us how the properties & actions of all corporeal things follow from those manifest Principles, would be a very great step in Philosophy, tho the occult causes of those Principles were not yet discovered: & therefore I scruple not to propose the Principles of motion above mentioned, they being of very general extent.
Now by the help of these Principles all material things seem to have been composed of the hard & solid Particles above mentioned variously associated in the first creation, buyt not without the counsel of an intelligent aAgent. For it became him who created them to set them in order. And if he did so, it's unphilosophical to seek for any other origin of the world, or to pretend that it might arise out of a Chaos by the mere laws of Nature; tho being once formed it may continue by those laws for many ages. For while Comets move in very excentrick Orbs in all manner of positions, blind fate could never make all the Planets move one & the same way in orbs concentrick, some inconsiderable irregularities excepted wchwhich may have risen from the mutual actions of Comets & Planets upon one another, & wchwhich will be apt to increase till this Systeme wants a reformation. Such a wonderful286 wonderful uniformity in the Planetary Systeme must be allowed the effect of choise. And so must the uniformity in the bodies of Animals, they having generaly a right side & a left side shaped alike & on either side of their bodies two leggs behind & either two arms or two leggs or two wings before upon their shoulders, & between their shoulders a neck with a head upon it, & in the head two ears, two eyes, a nose, a mouth & a tongue alike situated. Also the first contrivance of those very artificial parts of animals, the Joynts, Muscles, Glands, Eyes, Ears, Brain, Nerves, Muscles, Glands, heart, Lungs, Midriff, Larynx, Hands, Wings, Swimming bladders, natural Spactacles, & other Organs of sense memory & motion, & the instinct of Brutes & Insects, can be the effect of nothing else then the wisdome & skill of a powerfull ever living Agent; who is being indivisibly in all places, after some such manner as that wchwhich thinks in us is in all parts of our sensorium, perceives all things accurately in their true solid dimensions by the immediate presence of the things themselves, while that wchwhich thinks in us perceives only the superficial pictures of the things made in our sensorium by motion conveyed thither from the things; & who is more able by his will to move the bodies wthwithin his boundless uniform unorganized sensorium & thereby to forme & reform the parts of the Universe, then we are by our will to move the parts of our bodies own bodies. ✝ ✝And yet we are not to consider the world as the body of God or the several parts thereof as the parts of God. They are his creatures subordinate to him & subservient to his will. And he is no more the soul of them then the soul of a man is the soul of the species of things carried through the Organs of sensaetion into the place of sensation where the soul by means of its presenc immediate presence perceives them. And since space is divisible in infinitum & matter is not necessarily in all places, it must be also allowed that God is able to create particles of matter of several sizes & figures & in several proportions to space & perhaps of different densities & forces, & thereby to vary the laws of Nature & make worlds of different sizes sorts in several parts of the Universe. At least I see nothing of contradiction in all this.
As in Mathematicks so in Natural Philosophy the investigation of difficult things by the method of Analysis ought ever to precede the method of Composition. This Analysis consists in arguing making experiments & observations & in arguing by them from compositions to ingredients & from motions to the forces producing them & in general from Phænomena & effects to their causes & from particular causes to more general ones, till the Argument end in the most general: The Synthesis consists in assuming the causes discovered & established, as Principles; of Phæno & by them explaining the Phænomena proceeding from them, & proving the explanations. In the two first Books of these Opticks I proceeded by Analysis to discover & prove the original differences of the rays of light in respect of refrangibility reflexibility & colour & their alternate fits of easy reflexion & easy transmission & the properties of bodies both opake & pellucid on which their reflexions & colours depend: & these discoveries being proved may be assumed as Principles in the method of Composition for explaining the phænomena arising from them them: an instance of wchwhich Method I gave in the end of the first Book. In this third Book I have only begun the Analysis of what remains to be discovered about light & its effects upon the frame of Nature, hinting several things about it & leaving the hints to be examined & improved by the further experiments & observations of such as are inquisitive. And if Natural Philosophy in all its parts, by pursuing this Method, shall at length be perfected, the bounds of Moral Philosophy will be also enlarged. For so far as we can know by Natural Philosophy what power is the first Cause, what power he has over us, & what benefits we receive from him, so far orour duty towards him as well as that towards one another will appear to us by the light of Nature. And no doubt, if the worship of false Gods had not blinded the Heathens, their Moral Philosophy would have gone further then to the four Cardinal Vertues. & instead of teaching us the transmigration of Souls, & to worship the Sun & Moon & dead Heroes, they would have tought us to worship orour true Author & Benefactor.
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Qu. 20. Are not the rays of light very small bodies refracted by means of certain attractions which intercede then & the parts of pellucid bodies? For we have s The common opinions are that light is made either by pression or motion propagated through a fluid or by bodies projected. If it consisted only in pression propagated without actual motion, it would not be able to agitate & heate the bodies wchwhich refract & reflect it. If it consisted in motion propagated to all distances in an instant, it would require an infinite force to generate that motion. Light moves in right lines without bending or spreading into the shadow beyond the bounds of those right lines in wchwhich it begins to move. But pression or motion cannot be propagated in a fluid in right lines beyond an obstacle wchwhich stops part of the motion; but bends & spreads every way into the quiescent medium wchwhich lies beyond the obstacle. Gravity tends downwards, but the pressure of water arising from gravity tends every way with equal force & is propagated as readily & with as much force side ways as downwards & through crooked passages as through streight ones. The waves of on the surface of water passing by the sides of a broad obstacle bend & dilate themselves gradually into the quiet water behind the obstacle. The waves pulses or vibrations of the Air wherein sounds consist bend manifestly tho not so much as the waves of water. For a Bell or a Canon may be heard beyond a hill wchwhich intercepts the sight of the sounding body & sounds are propagated as readily through crooked pipes as through streight ones. But light is never known to follow crooked passages nor to bend into the shadow For the fixt stars by the interposition of any of the Planets cease to be seen & so do the parts of the Sun by the interposition of the Moon Mercury or Venus. The rays wchwhich pass very neare to yethe edges of bodies any body are bent a little by the action of the body as we shewed above; but this bending is not towards but from the shadow & is performed only in the passage of the ray by the body. So soon as the ray is past the body it goes right on.
To explain the double unusual refraction of Island-Crystal by pression or motion propagated has not hitherto been attempted (to my knowledge) except by Hugenius who for that end supposed two several vibrating Mediums within that crystal: but when he found tried the refractions in two successive pieces of ytthat crystal & found them such as is mentioned in the two last preceding Questions; he confest himself at a loss for explaining them: For pressions or motions propagated from a shining body through an uniform medium must be on all sides alike: whereas by those experiments it appears that yethe rays of light have different properties in their different sides. He suspected that the pulses of Æther in passing through the first crystal might receive certain new modifications wchwhich might determin them to be propagated in this or that Medium within the second crystal according to the position of that second crystal: but what modifications those might be he could not say nor think of any thing satisfactory in this point.: And its more difficult to think conceive how such modifications can be in the rays originally, if light be nothing else then pression or motion propagated through fluids. For the refractions reflexions inflexions and288 inflexions & colours of light depend on such properties as are in the rays originaly & suffer no change by the passing of the rays through several mediums: & therefore all Hypotheses are to be laid aside in wchwhich those phænomena are derived from new modifications of the rays.
By the regular & very lasting motions of Comets & Planets through the heavens in all manner of positions its manifest that the heavens are void of all sensible resistence [& therefore may let the rays of light go through them in right lines with an uniform motion to very great distances, although those rays should be bodies]. The resistance of fluid Mediums arises partly from the attrition of the parts of the Medium & principally from the Vis inertiæ of the matter. That part of the resistance which arises from the attrition of the parts may be diminished by dividing the matter into smaller parts & making the parts more smooth & slippery: but that part of the resistance wchwhich arises from the Vis inertiæ is proportional to the density of the matter & cannot be diminished by dividing the matter nor by any other means then by decreasing the density. And for these reasons the density of fluid Mediums is very nearly proportional to their resistance Water is 13 or 14 times lighter then water Quicksilver, & by consequence 13 or 14 times rarer, & it's resistance is less then that of Quicksilver in the same proportion or thereabouts as I have found by Pendulums. The op Air in wchwhich we breath. The open Air in wchwhich we breath is eight or nine hundred times lighter then water, & by consequence 8 or 900 eight or nine hundred times rarer, & accordingly its resistance is less then that of water in the same proportion or thereabouts as I have also found by Pendulums.. And the thinner the Air the less its resistance And if the Air be made still thinner & thinner its resistance becomes less & less untill it becomes insensible. And in thinner Air the resistance is still less & by rarefying the air becomes at length insensible. For feathers falling in the open Air meet with great resistance but in a tall glass wall emptied of Air they fall as fast as lead or gold as I have seen tried several times. And the heavens are emptier of Air then any Vacuum we can make below & therefore have less resistance. Liquors wchwhich differ not much in density, as water spirit of wine spirit of Turpentine, hot oyle, differ not much in resistance, & the reason is because their rersistances arise chiefly from their Vis inertiæ. Heat increases fluidity & makes many bodies fluid wchwhich are solid not fluid in cold & accordingly decreases their resistance as may be tried in oyle but decreases not the resistance of water considerably as it would do if any great part of its resistance arose from the attrition or tenacity of its parts, & therefore the vis inertiæ resistence of water arises chiefly from the Vis inertiæ; & by consequence if the heavens were as dense as water they would not have much less resistence then water, if as dense as quicksilver they would not have much less resistence then quicksilver, if absolutely dense or full of matter without any Vacuum, let the matter be never so fluid, they would have a greater resistance then Mercury Quicksilver. A solid globe in such a Medium would lose above half its motion in moving less then three times the length of its diameter & a globe not solid would be retarded sooner. And therefore to make way for the lasting motions of Comets & Planets its necessary to empty the heavens of all matter except perhaps some very thin vapors steams or effluiaeffluvia air or æther arising from the Atmospheres of the Earth Planets & Comets. Such matter is of no use for explaining the Phenomena of nature, the motions of the Planets & Comets being better explained without it by gravity without it, & gravity not being hitherto explained by it. It serves only to disturbe & retard the motions of those great bodies & make the frame of nature languish & in the pores of bodies it serves only to stop the vibrating motions of their parts wherein their heat & activity consists.. And as it is of no use & hinders the operations of nature & makes her languish so there is no evidence for its existence; & therefore it ought to be rejected. And if it be rejected, the Hypotheses that light consists in pression or motion propagated through289 through such a Medium are rejected with it. And for rejecting such a Medium we have also the authority of those the oldest & most celebrated Philosophers of Greece & Phenicia, (Mochas, Phirecides, Thales, Pythagoras who made a Vacuum, Atoms & the gravity of Atoms the first principles of their philosophy
I have therefore proposed the Question whether the rays of light may not be small bodies emitted by shining substances. Certainly the resemblance between them rays & bodies such bodies is very great. For such such bodies will pass through uniform Mediums in right lines without bending into the shadow wchwhich is the property of the rays of light. Pellucid substances act upon the rays of light at a distance in refracting reflecting & inflecting them, & the rays mutually agitate the parts of those substances at a distance for heating them, & this action & reaction very much resembles an attractive force. If refraction be performed by attraction of the rays, the sines of incidence must be to the sines of refraction in a given proportion as we shewed in orour Principles of Philosophy; & this Rule is true by experience. If the rays of light in going out of a glass into a Vacuum fall too obliquely on the Vacuum, they are totaly reflected wchwhich seems to argue an attraction of the glass. Colours & Refractions depend not on new modifications of light but on the original & unchangeable properties of its rays, & such properties are best conserved in bodies projected. Pressions & motions are apt to receive new modifications in passing through several Mediums but the properties of bodies projected will scarce be altered thereby. Nothing more is requisite for producing all the variety of colours & degrees of refrangibility then that the rays be bodies of different sizes the least of wchwhich may make violet the weakest & darkest of colours & be more easily diverted by refracting surfaces from the right course, & the rest, as they are bigger & bigger may make the stronger & more lucid colours, blue green yellow & red
& be more & more difficultly diverted. And lastly the unusual refraction of Island Crystal looks very much as if it were performed by some kind of polar attractive vertue attraction lodged in certain sides both of the rays & iof the particles of the crystall. For were it not for some kind of polar disposition or vertue in some sides of the particles of the crystal wchwhich derives is not in their other sides & wchwhich inclines & bends the rays towards the coasts of unusual refraction the rays wchwhich fall perpendicularly on the crystal would not be refracted towards that coast when they fall perpendicularly on the glass crystal rather then towards any other coast, Both at their incidence & at their emergence, so as to emerge perpendicularly by a contrary situation of yethe coast of unusual refraction at the second surface; the crystal acting upon the rays after they have past through it & are emerging into yethe air or if you please into a vacuum. And since the crystal by this disposition or vertue does not act upon the rays unless when one of their sides of unusual refraction are lookare turned towards that coast this argues a vertue or disposition in those sides of the rays which answers to & sympathizes with that vertue or disposition of the crystal, as the poles of two Magnets answer one to another. And as magnetism is not found in all bodies may be intended & remitted & is found only in the Magnet & in iron, so this vertue of refracting the perpendicular rays is greater in Island Crystal less in Crystal of the rock & is not yet found in other bodies. But what ever this vertue be 'tis290 tis very difficult to conceive how the rays of light, unless they be bodies, can have a permanent vertue in two of their sides opposite one to another wchwhich is not in their other sides, & this without any dependence on the Medium through wchwhich they are propagated; the like sides of several rays not looking all towards the same coast but being turned several ways before their incidence on the first crystal, & looking indifferently towards any coast as yethe rays happen to be emitted from shining substances in several positions, & accordingly as they are turned to this or that coast, being refracted at their incidence on yethe first crystal & again at their emergence out of it some after the usual & some after the unusual manner.
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What is it by means of wchwhich bodies act on one another at a distance. And To what Agent did the Ancients attribut the gravity of their atoms. And is there not something in all space of matter Or And what did they mean by calling God an harmony & comparing him & the material part corporeal part of the Universe to the corporeal world matter to yethe God Pan & his Pipe.
Can any space be wthwithout something in it & what is that something in space void of matter [& what are its properties & operations on matter]
When water Oyle of Vitriol is run per deliquium & in destillation the water ascends difficultly & brings over with it a good pa some part of yethe oyle of Vitriol in the form of spirit of Vitriol & this spirit being poured upon iron copper or salt of tartar unites with the body & lets go the water: does not this shew that the acid spirit is attracted by the water & more attracted by the fixt body then by the water & therefore lets go the water to close with the fixt body. And is it not for the same reason that the water & acid spirits in Vinegar, Aqua fortis or Spirit of salt the water & acid spirits cohere & destill rise dtogether in destillation; but if the menstruum be poured on salt of tartar of on Lead or iron or any fixt body wchwhich it can dissolve the acid by a stronger attraction lets go the adheres to yethe body & lets go the water. And its it not from
of tartar or quick lime the sulphur by a stronger attraction lets go yethe Mercury & to & by a stronger attraction u univtes with yethe fixt dbody & that in the sublimationing Mercury sublimate is sublimed from ♁ or from Regulus of ♁ the spirit of salt lets go yethe ♀ & by a stronger attraction unites wthwith yethe antimonial metall & destills with it till stays with it till the heat be big enough to make them both ascend together & then subl carries up the metal in the form of a very flui fusible salt called butter of Antimony, although the Antimony will alone would will not ascend, alone alone being almost as fixed as lead.
When aqua fortis dissolves silver & not gold & aqua regis dissolves gold & not silver may it not be said that Aqua fortis is subtile enough to penetrate ☉as well as silver but wants the attractive force wchwhich to give it entrance & that Aqua Regis is subtile enough to enter penetrate silver but wants the attractive force to give it entrance. For aqua Regis is compounded of Aqua fortis [wchwhich is subtile enough to enter silver:] &: common salt added to Aqua fortis enables the menstruum to dissolve gold tho the common salt be a gross body. When therefore When therefore And spirit of salt predcipitates silver out of Aqua fortis by is it not by attracting & mixing wthwith yethe aqua fortis & repelling the silver. And when water precipitates Antimony out of sublimate of Antimony & Salarmoniac or out of butter of Antimony, is it not done by attracting & dissolving & weakening the salarmoniac or the spirit of salt & repelling the Antimony. Is it not therefore also for want of an attractive vertue between the parts of water & oyle, of Quicksilver & Antimony, Lead & Iron that these substances do not mix & by several degrees of an a strong attractive vertue that some bodies mix readily as Quicksilver & Tin, Antimony & Iron, Water & salts & by a weaker one that others mix difficultly as Quicksilver & copper? And is it not in general from yethe same principle that heat congregates homogeneal th bodies & seperates heterogeneal ones.
When Arsnick with soap — — — in sublimation.
When Mercury sublimate sublimed wthwith fresh Mercury becomes dulcis — — — — more strongly. by adhering strongly to the metal
When
And Does not the sharp & pungent tasts of acids arise from the strong attraction whereby the pacid particles rush upon the p & agitate the particles of the tongue? For And when metals are dissolved in acids menstruums, do not the acids adhering to the metallic particles must loose loose much of their activity & act in a different manner & so that the compound has a different tast much milder then before. & sometimes a sweet one. And if the acids be in too small a proportion to make the compound dissolvable in water, the compound remains will it not the acid become unactive & lose its will d not acid loose its be tast & the compound be a tastles earth? For such things as are not dissolvable by the moisture of the tongue cannot act not upon the tast
As
And from yethe endeavour of yethe particles of Air to reced from onegros another bodies it comes to pass that Air is rarer in very slender pipes of glass then in free spaces & by reason of its rarify presses less upon the surface of water into wchwhich the lower end of yethe pipe is dipt, then air withou yethe air presses upon it & so gives leave to air yethe water to ascend in the pipes wchwhich is the ground of philtration.
Qu. 21. Do not bodies & light mutualy change into one another. And are are not not bodies composed either wholy or in great measure from composed of the particles of light And do may not bodies in great measure receive their act most active powers from the particles of light of wchwhich they are composed enter their composition? For all fixt bodies emit light so long as are they continue sufficiently hot & light light mutualy stops in bodies as often as its rays strike upon their parts, as we shewed above. I know no body less apt to shine then water & yet water by frequent destillations passes changes into fixed earth & this earth shines as much by heat as any other body. The changing of bodies into light & light into bodies s is very conformable to the course of nature which seems to delight in transmutations. Water wchwhich is a very fluid volatile tastles salt she changes by heat into vapour wchwhich is by in yethe form of air wchwhich is a sort of air & by cold into into ice wchwhich is a hard pellucid fus brittle tast fusible stone, & this stone returns into water by heat & vapour returns into water by cold. Earth by heat becomes fire & by cold returns into earth. Dense bodies by fermentation yeild or turn into air & dry fumes exhalations & return rarefy into several sorts of aer & this aer & theise aereal substance by fermentation & sometimes without it return into dense bodies. [Quicksilver dropt into a red hot earthen retort ascends in yethe form of water vapour wchwhich recondenses into a pellucid liquor like common water in appearance & this liquor being left a few days in the cold air returns in Quicksilver]. All Animals & vegetables Birds Beasts & Fishes, Trees & other Vegetables with their several parts grow out of water & watry tinctures & by putrefaction return again into watry substances. And water standing a few days in the open Air yeilds a tincture wchwhich (like that of Mault) by standing longer lets yeilds a sediment & a spirit, but before putrefaction is fit nourishment for animals & vegetables And the if bodies turn into light & light return into bodies, 'tis a transmutation like the st not agreable to yethe proceeding of Natures works in the rest of her works.
Mercury appears sometimes in the form of a fluid ponderous opake bright tastles Metal, sometimes in the form of a hard metal brittle metal sometimes in the form of a corrosive pellucid salt called sublimate or in ytthat the of a tastles pellucid volatile earth called Mercurius dulcis, or of an a red opake volatile body ca volatile earth called cinnaber or of a red or white precipitate, or in the form of a fluid salt or in that of air or of common water ✝ ✝ for & being dropt into a red hot earthen Retort it destills in the form of common water. & after all these & other changes it returns again into Mercury ‡ ‡ & being agitated in vacuo it shines.
Now since light is the most active of all bodies known to us, & enters the composition of all natural bodies, why may reccon it not be the chief principle of activity in bodies them? Attraction ought to be strongest in the smallest particles in proportion to their bulk. Tis much stronger in small magnets in proportion to their bulk then in great ones. And considering how soft the much the rays of light are bent at their entrance into pellucid bodies, we may reccon that yethe attriactive power of the ray of light in proportion to its bulk the body is as much greater then the gravity of a projectile in proportion to its bulk body as the bent velocity of the ray of light is greater then the velocity of the projectile & the bent of the ray greater then the bent of the line of described by the projectile, together supposing the inclination of the ray to refracting surface & that of yethe projectile to yethe Horizon to be alike. And by this proportion I reccon the attractive force of rays of light above a million of million of time ten hundred thousand thousand millions of times greater then the force force whereby bodies gravitate on yethe surface of this earth in projortionproportion to the matter in them. supposing that light comes from the Sun to us in about 7 minutes of an hour. And so great a force in the rays cannot but have a very great effect upon the particles of matter wthwith which they are compounded, for causing them particles to attract one another. Let us therefore see if they be have not such mutual attractions among between the particles of matter.
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supposing the bodies of equal vertue when equal Now attraction in bodies of the same kind & vertue is strongest in the smallest bodies of the same kind in proportion to their bulk. It is found stronger in small magnets for their weight then in great ones. weight for weight And the For the parts of small ones being close together unite their forces more easily. And therefore the rays of light being the smallest bodies known to us, we may expect to find it their attraction very strong in them. And how strong it is may be gathered something nearely by this Rule. The attraction of a ray of light in proportion to its body is to yethe gravity of a projectile in proportion to its body, as in a compound ratio of the velocity of the ray of light to the velocity of the projectile & of the bent of the ray to the bent of the projetile, supposing the
We have laid down reasons why shewed that the attraction of
The smallest particles of matter may cohere by the strongest attractions & compose bigger particles of weaker vertue & the many of these may cohere & compose a bigger particles whose vertue is still weaker & so on for divers successions untill the progression end in the biggest particles on which the operations in Chymistry & the colours of natural bodies depend, & wchwhich by cohering together compose bodies of a sensible magnitude.
Since metals dissolve in acids are satiated with attract but a smal quantity of the acid, their attractive force can reach but to a small distance & the from them. And as in Algebra where affirmative quantities vanish & cease, there negative ones begin so in Mechanicks where attraction ceases there a repulsive vertue ought to begin. [By this vertue the rays of light are emitted from shining substances & reflected by bodies & by the bodies they fall upon & in their passage by the sides of bodies they are bent from the body. And by the same power the particles of air recede from one another, flys walk upon water without wetting their feet, & all dry things are difficultly made to touch one another, & Object glasses of long Telescopes laid upon another will scarce touch so as to make the black spot appear (as is described in yethe Observation of yethe 1t part of the second book) unless they be pressed together, & when yethe pressure ceases the glasses recede from one another.] And that there is such a verturevertue seems to follow from the reflection & inflexion of light. For in both these cases the rays of light are repelled without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of of light the ray so soon as it is shaken off from a shining body from by the vibrating motion of these parts of the body & gets beyond the reach of attraction being driven away wthwith exceeding great velocity. For that force wchwhich is great enough to turn it back in reflection may be great enought to give it its motion in emission. It seems to follow also from the production of air vapour the particles of such bodies when shaken off from yethe bodies by heat &or fermentation, so soon as they are beyond the reach of attraction flying recedieng from yethe bodies & also from one another with great strength & keepieng at a distance. For The particles of fluids wchwhich by reason & the do not adhere too strongly to one another & are of such a smallness as renders them most susceptible of those agitations wchwhich them keep liquor in a fluor, being most easily rarefied, or to use the language of yethe Chemists, being most volatile. These rarefy into vapor by an easy heat & condense with by cold: but those wchwhich are larger & less susceptible of agitation or cohere by a stronger attraction are not seperated without a stronger heat or perhaps not without fermentation. And these last are the bodies wchwhich Chemists called fixed & wchwhich byeing rarefied become true permanent air; those particles receding from one another with the greatest force wchwhich upon contact cohere most strongly. And because the particles of permentpermanent air are grosser & denser then those of vapors, thence it is that true air is more ponderous thethen vapour & that a moist Atmosphere is lighter then a dry one, so quantity for quantity, as ned by the Barometer.
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The Anticat Philosphers who [held atoms, that & vacuum & attributed to every atom a gravitayting power proportional to yethe matter conteined in it, knew of understanding by atoms the least particles of matter & accounting them indivisible not by reason of their littleness but by reason of their being solids void of all parts,] And for rejecting such a Medium we have yethe authority of those oldest & most celebrated Philosophers who made Atoms, Vacuum & yethe Gravity of Atoms the first principles of their Philosophy, ascribing to understanding by atoms the least particles of matter & accounting them indivisible not by reason of their littleness but byecause of their being solids void of all pores, & attributing to every atom a gravity proportional to yethe quantity of its matter, without assigning the cause of such a gravity.
1 Move in right lines. 4 reflected entire at going out of glass. 5 Original properties immutable no new modifications. 3 double proportion of sines. 2 act at a distance. 6 double refraction.
It deserves therefore to be considered I have therefor proposed the Question whether the rays of light may not be small bodies trayected from the emitted by shinning substances. & that for these reasons. 1 because Certainly the resemblance between them is very great. For such bodies will pass through uniform Mediums in right lines without bending into yethe shadow wchwhich is the property of yethe rays of light. 2 because Bodies Pellucid substances act upon the rays of light at a distance in refracting reflecting & inflecting them, wchwhich & the rays mutually agitate the parts of bodies those substances at a distance for heating them wchwhich & this action & reaction very much resembles an attractives force between the rays & the particles of refracting bodies 3 Because If refraction be performed by attraction of yethe rays, the sines of incidence must be to the sines of refraction in a given proportion as we shewed in orour Principles: & aAnd this Rule is true by experience. 4 Because If The rays of light in going out of glass if they into a vacuum fall too obliquely on yethe glass are air vacuum they are totally reflected, [the attraction of yethe glass seeming to overcome the force of yethe ray to on into Air, oblique rays more directly them] wchwhich seems to be by the attraction of yetheglass. 5 Because The may be by them which seems to an attraction of the glass Colours & refractions of light depend not on new modifications of light but upon the original & unchangeable properties of its rays without any new modifications impressed on them, & such properties are best conserved in bodies projected. Pressions & motions may may are apt to receive new modifications in passing through several mediums but the properties of bodies projected r are not will scarce be altered 6 The thereby. Nothing more is
requisite for yethe production of all colours & diversity of colours & degrees of refrangibility then but that the rays be bodies of different sizes, the least of wchwhich may make violet the darkest of colours violet, & be most easily diverted by refraction from the right course & the rest as they are bigger & bigger may make the rest of yethe more lucid colours blue green yellow & red, & be more & more difficultly diverted by the refracting surface. And lastly the unusual refraction of Island Crystal looks very much as if it was performed by some kind of polar vertue both in the rays & in the particles of the crystal. For were it not for some kind of polar vertue in the rays particles of yethe crystal the r wchwhich draws the rays towards the coast of unusual refraction the rays would not be refracted towards that coast when they fall perpendicularly on yethe glass. And were since the crystal by this vertue does not act upon yethe rays unless when their sides of unusual refraction are towards that coast this argues a virtue in those two sides of yethe rays wchwhich answers to ytthat vertue of yethe particles of yethe crystal as the poles of two Magnets answer one to another And as Magnetism is not found in all bodies & may be intended & remitted so this vertue of refracting the perpendicular rays is not found in all refracting substances & is greater in Isl greater in Island Crystal less in Crystal of the rock. then in Island Crystal But what ever this vertue be tis very difficult to conceive how the rays of light unless they be bodies can have convert a permanent original vertue in two of their sides opposite one to another wchwhich is not in their other two sides; & before their incidence on yethe first glas crystal be turned all manner of ways as they happen to be casually emitted from shining substances & this without any dependance on the nature of the Medium through wchwhich they are propagated; the like sides of several rays looking towards several coasts before their incidence on the first glass crystal, & being turned indifferently to towards any coast as the rays happen to be emitted from shining substance in several positions, & accordingly as they are turned to this or that being refracted by at their incidence on the first crystal some after the unusual & some after the usual manner
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And do not hot bodies communicate their heat to contiguous cold ones by the vibrations of this Medium propagated from them into the cold ones. ☉1 And do not the vibrations of this Medium in hot bodies contribute to the duration of their heat?
Pag. 133. lin. ult. After the word [parts?] add. And do not all bodies which abound with terrestrial parts & especially with suphureous ones, emit light as often as those parts are sufficiently agitated; whether that agitation be made by heat, or by friction or percussion or putrefaction or by any vital motion as in glow worms & the eyes of some animals or by any other cause or any other cause? as for instance, Sea-water in a raging storm, quicksilver agitated in vacuo; the back of a Cat or neck of a horse obliquely struck or rubbed in a dark place; wood flesh & fishes while they putrefy; Vapors arising from putrid waters usually called Ignes fatui; stacks of moist hay or corn in fermentation growing hot by fermentation; glow worms & the eyes of some animals by vital motions; the vulgar Phosphorus agitated by the attrition of any body or by the acid particles of the Air; Ambar & some Diamonds by striking pressing or rubbing them; scrapings of steel struck off with a flint; iron hammered very nimbly till it becomes red hot it becomes so hot as to kindle sulphur thrown upon it; the axe trees of charionts taking fire by the rapid rotation of the wheels; and some liquors mixed with one another whose particles come together with an impetus; as Oyl of Vitriol destilled from its weight of Nitre & then mixed with twice its weight of Oyle of Annisseeds. So also a hollow globe of glass about 8 or 10 inches in diameter, being put into a frame where it may be turned swiftly round its axis, will in turning shine where it rubs against the palm of ones hand applied to it, & if at the same time a piece of white paper or white cloth or the end of ones finger be held at the distance of about a quarter of an inch or half an inch from the glass that part of the glass where it is most in motion, the electric vapour which is excited by the friction of the glass against the hand, will by dashing against the white paper cloth or finger be put into such an agitation as to emit light & make the white paper, cloth or finger appear lucid like a glow worm.
Pag. 134 lin. ult. After the word [flame] add: When Gun-powder takes fire it goes away into flaming smoak. For the charcoal & sulphur easily take fire, & set fire to yethe Nitre, & the spirit of the Nitre being thereby rarefied into vapour, rushes out of the Nitre with explosion much after the manner that the vapour of water rushes out of an olipile; & the sulphur also being volatile is converted into vapor & thereby augments the explosion. Also the acid vapor of yethe sulphur (namely that wchwhich destills under a Bell into Oyle of Sulphur) entring violently into the fixt body of the Nitre, sets loose the spirit of the Nitre, & excites a great fermentation whereby the heat is further augmented & the fixt body of the Nitre is also rarefied into fume, & the explosion thereby made more vehement & quick. For if Salt of Tartar be mixed with Gun pouder & that mixture be warmed till it takes fire; the explosion will be still more violent & quick then that of Gunpowder alone: which cannot be from any other cause then the action of the vapor of the Gunpouder upon the action of the salt of Tartar whereby that salt is rarefied. The explosion of Gunpowder arises therefore from the quick & violent wh action whereby all the mixture being quickly & vehemently heated, is rarefied & converted into fume or vapour: which vapour by the violence of that action is at the same time heated & becoming red hot appears in the form of flame.
Pag. 137 l 135 lin. 16. After the words, [arise from them?] add For if water is made warm in any pellucid vessel, & the Aer is afterwards drawn out of the vessel, that water in the vacuum will bubble & boyle as vehemently as it would in the open aer in a vessel set upon the fire in the open till it conceives a much greater heat. For the weight of the incumbent Atmosphere keeps down the vapours & hinders the water from boyling untill it grow much hotter then is requisite to make it boyle in Vacuo. Also a mixture of Tinn & Lead being put upon a red hot iron in vacuo, emits a fume & also a flame295 flame: but the same mixture in the open air, by reason of the weight of the incumbent Atmosphere does not so much as emit any fume which can be perceived by sight. In like manner the great weight of the Atmosphere which lyes upon the globe of the Sun, may hinder bodies there from rising & going away from the Sun in the form of vapours & fumes unless by means of a far greater heat then that which in the superficies of orour Earth would very easily turn them into vapours & fumes: and the same great weight may again condense those vapors & exhalations as soon as they shall ascend from the Sun, & make them presently fall back again into the globe of the Sun, & by that action increase the heat of the Sun much after the manner that in our earth the Aer increases the heat of a culinary fire. And the same weight may hinder the globe of the Sun from diminishing being diminished unless perhaps by the emission of light, & a very small quantity of vapors & exhalations.
Pag. 134 lin 1 insert Qu. 18B. Do not electric bodies by friction emit a subtile exhalation or spirit by which they perform their attractions? And is not this spirit of a very active nature & capable of emitting light by its agitations? And may not all bodies abound with such a spirit & shine by the agitations of this spirit within them when sufficiently agitated by heated? For if a larglonge & round cylindrical piece of Ambar be rubbed nimbly it will shine in the dark & if when it is well rubbed the finger of a man be held neare it so as almost to touch it, the electric spirit will rush out of the Ambar & with a soft crackling noise like that of green leaves of trees thrown into a fire, & in rushing out it will also push against the hand so finger so as to be felt like the ends of hairs of a fine brush touching the finger. And when the globe of glass above mentioned is exhausted of air & nimbly turned round about its axis, & in turning round is rubbed against the inside of a man's hand so as to shine where it touches the hand. And when And the like happens in glass. If a cyl long hollow tube of flint glass about an inch be rubbed nimbly with a paper held in the hand till the glass begins to grows warm, it will in rubbing emit light & the face or any other tender part of the skin being held neare that part of the glass where it has been most rubbed, the electric spirit which is excited by the friction & rushes out will rush out of the glass with a cracking noise & push against the skin so as to be felt, & in pushing emit light so as to make the skin shine like rotten wood or a glow worm. And if little the glass was held neare pieces of leaf brass were scattered upon a table they would be pieces would b electric spirit wchwhich issued out of the glass would put them pu into various brisk motions at the rea stir them at the distance of 6, 8 or 10 inches or a foot, & put them into various brisk motions, so making them sometimes leap towards the glass & stick to it, sometimes leap from it with great force, & sometimes move towards it & from it several times with reciprocal motion, somtimes move in lines parall to the tube, sometimes remain suspended in the air, & & sometimes move in various curve lines. Whisch motions shew that this spirit is agitated in various manners like a wind. And if a broad plate of glass be placed between the Tube & the pieces of brass, yet the Tube will attract them them, tho not so strongly as when the plate of glass is taken away. Which shews that the electrick spirit is so subtile as readily to pass through glass tho not so readily as through the Air. And whilst it pervades dense bodies so easily, why may it not be latent in them all in some measure or other, & tho those only emitt it by friction in which it abounds most copiously? And since it easily emits light by agitation, why may it not emit light in all dense bodies heated red hot & thereby cause them to shine?
These And do these colours vanish in a second or two of time when the eye & the finger remain quite? But if while the eye is at rest the finger is moved forward & backward alternately, do they not appeare again so long as the And if the eye & the finger remain quiet these colours vanish t in a second or two of time. But if the finger is moved backwards & forwards & backwards alternately these colours appear again while the finger is in motion. Do not — — — stroke? And when a coale of fire moved nimbly in the circumference of a circle makes the whole circumference appear like a coale circle of fire; is it not because the motions excited in the bottom of the eye by the rays of light are of a lasting nature & continue till the ca coale in going round returns to its former place? And are not these lasting motions excited by or by press in the bottom of the eye of a vibrating nature?
Qu. 17. If a stone be thrown into stagnating water the vibrations undulations excited thereby continue for some time in the place where the stone fell into the water, & are propagated thence in concentric circles to great distances. And when When light is refracted or reflec falls upon the surface of any pellucid body & is there refracted or reflected: do not the vibrations thereby excited in the refracting or reflecting Medium at the surface of the pellucid body continue as long as when they are excited in the bottom of the eye by the pressure & motion of the finger or by the light wchwhich comes from the the coale of fire in the experiments above mentioned? And are not these Vibrations propagated from thence to great distances? And do they not overtake the rays of light, & by overtaking them successively do they not put the rays into the fits of easy reflexion & easy transmission described above?
Qu. 18. If 2 two little Thermometers be placed suspended 1 in two larg & tall cylindrical vessels of glass inverted, 3so as not to touch the vessels, & the air be drawn out of one of these vessels: When these vessels are carried into a warm place the Thermometer in vacuo will grow warm almost as soon as the other Thermometer which is not in vacuo. And when the vessels are carried into a cold place, they Thermometers will g in vacuo will grow cold almost as soon as the other Thermometer. Is not the heat of the warm room conveyed through the Vacuum by the vibrations of a much subtiler Medium. then air wchwhich after the Air is drawn out remains in the Vacuum. And is not this Medium the Medium by wchwhich light is refracted & reflected? And doth not light communicate heat to bodies by exciting vibrations in this Medium.
Qu. 19. When light Doth not the refraction of light proceed from the different density of this Medium in different places the light receding from the denser parts of the medium towards the rarer parts thereof? And is not the density being thereof greater in free space & open spaces void of air & other grosser bodies then within the pores of water, glass, crystal & other compact bodies? [And do not the rays of light recede from the denser parts of the Medium towards the rarer & thereby become refracted?]
Qu. 20. Doth not this Medium in its pr passing out of water glass crystal & such lik other compact & dense bodies into empty spaces, grow denser & denser by degrees, & by that means refract the rays of light not in a point but by bending them gradually in curve lines? And doth not the graduall condensation of this Medium extend to some distance from the bodies & thereby cause the inflexions of the rays of light wchwhich pass by the edges of compact bodies at some distance from the bodies.
Qu. 21. Is not this Medium [rarest & within the densest bodies? such as are] And in passing from the Sun Moon Stars & Planets And is it not much rarer within the Sun & Starrs & Planets then &without them & in passing from them to great distances from them, doth it not grow denser & denser perpetually & thereby cause the gravity of those great bodies towards one another & of their parts towards the bodies, every body endeavouring to go from the denser parts of the Medium towards the rarer. For if a Medium grow be rarer at the distance of the tenth part of an inch from the Suns body, then at the distance of ten thousand thousand miles I Saturn from the Sun & still much rarer at the very surface of the Suns body be rarer within the suns body then at the distance of the tenth part of an inch from his body the Sun & if it be rarer at that distance from him then at the distance of Saturn from the Suns surface of the suns body then within him then at his surface & rarer there then at the distance of the tenth part of an inch from his body, & rarer then at the orb of Saturn: I see no reasōon why the increase of density should stop any where, & not rather be continued through all the distances from the Sun to Saturn & beyond. And tho this increase of density beyond the distance of the tenth part be at great distances may be exceeding slow yet if the elasticity force of this Medium be sufficiently great it may suffice
And in Mediums of the same density the for elastic force being in a duplicate ratio of the distance this forc swiftness of the vibrations the elastic force of this Medium must be 490000000000 times greater in proportion to its density then the elastic force of yethe Air is in proportion to its density.
I can see no reason why the increase of density should stop any where & not be continued through all the distances from the Sun to Saturn & beyond. And if the elastick force of this Medium may be very great, it may suffice to impel bodies from the denser parts of the Medium towards the rarer with all that force wchwhich wee call gravity. And that thise elastick force of this Medium is very great may be gathered from the swiftness of its vibrations. Sounds move about 1140 feet English feet in a minute second of time & therefo in eight minutes they move about 103 mile English miles. Light moves from the Sun to us in eight minutes & which distance is about 72000000 English miles supposing the horizontall Parallax of the Sun to be about 12″. And the vibrations of this Medium, that they may cause the alternate fits of easy transmission & easy reflexion must be swifter then & by consequence above 700000 times swifter then sounds. And therefore the elastick force of this Medium in proportion to its density must be above 700000 x 700000 times greater then the elastick force of the Air is in proportion to its density.
Qu
Qu. 22. Is not all sensation Is not vision performed by the vibrations of this spirit excited in the bottom of the eye by the rays of light? And is not hearing performed & propagated through the uniform solid & pellucid capellamenta of the auditory nerves in the place of sensation. And is not the performed by the vibrations either of this or some other Medium, (or of the Electric spirit, perha excited in the bottom of the eye by light on in the auditory nerves by the tremors of the air [& in the of nerve to the other senses by other motions; & propagated through the pellucid capillamenta of the nerves into the place of sensation] & propagated through their pellucid capillamenta into the place of sensation. And so of the other senses.
Qu. 23. Is not animal motion performed by the vibrations of this Medium excited in the brain by the power of the will & propagated from thence through the solid & pellucid capillamenta of the nerves into the muscles for contracting or dilating them? I suppose the capillamenta to be solid uniform & pellucid that the motion may be propagated along them uniformly without interruption.
Qu. 24. Do not electric bodies by friction emit a subtile exhalation or spirit by wchwhich they perform their attractions? And is not this Spirit – – – – – – – – – – – & thereby cause them to shine.
Qu. 25 Are there not other original properties of light – – – – –
Qu. 23. Is not electrical attraction & repulse performed by an exhalation wchwhich is raised out of the electrick body by friction & expanded & variously agita to great distances & variously agitated like a win turbulent wind. & wchwhich carryisng light bodies along with it. [For light bodies are not only attracted by electric bodies but also repelled & otherwise agitated in various manners. And But when the electric spirit begins to be re-condensed & by condensation to return into the electric body, doth it not it it carryess light bodies along with it towards the electric body & causes that attraction wchwhich we call electrick.] & agitates them in various manners according to it own motions, making them go sometimes towards the electric body, sometimes from it & sometimes move with various other motions? And when this spirit looses its turbulent motions & begins to be recondensed & by condensation to return into the electric body doth it not carry light bodies along with it towards the electrick body & cause them to stick to it without further motion till they drop off? And is not this exhalation much more subtile then common Air or Vapour? For electric bodies attract straws & such like light substances through gl a plate of glass interposed, tho not so vigorously. And may there not be other Exhalations & subtile invisible Mediums which may have considerable effects in the Phænomena of nature?
And the same experi things will be have been appear found by rubbing a long & large cylinder of glass or Ambar with a paper held in ones hand especially if the diameter of the cylinder of glass be an inch an inch or above & continuing the friction till the glass groews warm.
Qu. 31. May not the mutual attraction of the small parts of small bodies be sufficiently strong to make them cohere & cause the compose very hard bodies
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Qu. 17. Does not we the passage of light through dense transparent bodies, such as are water, oyle, salts , glass, crystall, spar, talk, & gemms, require that bodies be very much more porous then is usualy beleived? For if a ray of light A Magnet draws a Needle without any diminution of its vertue from the interposition of bodies not magnetical as such as are water glass or crystal, silver lead quicksilver or gold the densest & least porous of all bodies. And the gravitating cause acts without sensible impediment though the bodies of the eEarth & Planets to their very centers so as to make them gravitate towards the Sun & towards one another in proportion to all the matter in them, & by consequence so as to make their centerral parts as heavy towards the Sun & towards one another as their superficial parts are in proportion to their matter. And to explain these things mechanicaly requires that the densest bodies be exceeding porous. so as to let the causes of magnetism or gravity work through them without sensible impediment And whether this poroussity may not be also inferred from the passage of light through pellucid bodies is here inquired. W For whether yethe rays of light be small bodies or only motion or pression propagated from shining substances, they move in right lines, & if any a ray meet with any opposition whereby it is once turned out of the way it can never after return again into yethe right way unless by great accident. How bodies may be sufficiently porous to give free passage every way in right lines to the rays of light is hard to conceive but not impossible. For you have heard above that yethe colours of bodies arise from particles of certain sizes. If these particles be supposed to lye together with interstices or pores between them equal to the particles & to be compounded of other particles much smaller with intestices between them equall to yethe particles & those of others still much smaller with interstices equall to the particles & so on untill you come at solid particles equal to the pores void of all pores; & if there be three degrees of particles the least of wchwhich are solids, the body will have seven times more pores then parts; if four degrees the body will have 31 times more pores then parts least degrees of particles the least of wchwhich are solids the body will have 15 times more pores then parts, if five degrees the body will have 31 times more pores then parts, if six degrees it will have 63 times more pores then parts & so on. And there may be other contrivances unknown to us by wchwhich bodies the posousness of bodies may be still encreased
Qu. 18. Is not light refracted after several manners & by several sorts of powers? An instance of double refractions 17. Are there not other original properties of the rays of light besides those already described? An instance of another two of original property we have in the refractions of Island-crystal described first by Erasmus Bartholin & afterwards more exactly by Hugenius in his book oOf Light De la lumiere.. This crystal is a pellucid fusile stone Talk clear as water or crystal of yethe rock & without colour, enduring the fire a red heat without losing its transparency & in a very strong heat calcining without fusion. Steept a day or two in water it loses its natural polish. Being rubbed on cloth it attracts pieces of straws & other light things like Ambar or glass: & with Aqua fortis its makes an ebullition. It seems to be a sort of Talc & is found in form of an oblique Parallelopidped with six parallelogram sides & eight angles solid angles. The obtuse angles of the Parallelograms are each of them 101 degrees & 52 minutes, the acute ones 78deg. 8min. Two of the solid angles opposite to one another as C & E are compossed each of them with three of these obtuse angles & each of the other six with one obtuse and297 & two acute ones. It cleaves easily in planes parallel to any of its sides & not in any other planes. It cleaves with a glossy polite surface not perfectly plane but with some little uneavenness. It is easily scratcht with a point of & by reason of its softness it takes a polish very difficultly. It polishes better upon polished looking-glass then upon metal & perhaps better upon pitch leather or parchment. Afterwards it must be rubbed with a little oyle or white of an egg to fill up its scratches: whereby it will become very transparent & polite. But for several experiments it is not necessary to polish it. If a piece of this crystalline stone be laid upon a book every letter of the book seen through it will appear double by means of a double refraction. And if any beam of light falls either perpendicularly or in any angle upon any surface of this crystal it becomes divided into two beams by means of the same double refraction. Which beams are of the same colour with the incident beam of light & seem equal to one another in the quantity of their light or very nearly equal. One of these refractions is One of these refractions is performed by the usual rRule of Opticks, the sine of incidence out of Air into this Crystal being to the sine of refraction as five to three. The other refraction, wchwhich may be called the unusuall refraction, is performed by the following Rule.
Let ADBC represent the refracting surface of the Crystal, C the biggest solid angle at that surface, GEHF the opposite surface & CK a perpendicular on that surface. This perpendicular makes wthwith the per edge of the crystal CF an angle of 19deg. 3′. Joyne KF & in it take KL so that the angle KCL be 6deg 40′ & the angle LCF 12deg. 23′. And if ST represent any beam of light incident at T in any angle upon the refracting surface ADBC, let TV be the refracted beam determined by the given proportion of the sines 5 to 3 according to the usual rule of Opticks. Draw VX parallel & equal to KL. Draw it the same way from V in wchwhich L lieth from K, & joyning TX this line TX shall be the other refracted beam carried from T to X by the unusual refraction.
If therefore the incident beam ST be perpendicular to the refracting surface the two beams TV & TX into wchwhich it shall become divided shall be parallel to the lines CK & CL; one of those beams going through the crystall perpendicularly as it ought to do by the usual laws of Opticks, & the other TX by an unusual refraction diverging from the perpendicular & making with it an angle VTX of about 6 degrees, as is found by experience. And hence the plane VTX & such like planes wchwhich are parallel to the plane CFK may be called the planes of perpendicular refraction. And the coast towards wchwhich the the lines KL & VX are drawn may be called the coast of unusual refraction.
In like manner Crystal of the rock has a double refraction: but the difference of the two refractions is not so great & manifest as in Island Crystal.
Now I beleive it will easily be allowed that the usual re unusual refractions of these Crystalls are of a different kind from the usual, & performed by a different sort of power; they being performed by very different laws: and it may be enquired whether there are not still more kinds of refractions & refracting powers.
Qu. 18. Have not the rays of Light several original dispositions whereby they are determined to suffer several sorts of refraction? For in the foregoing experiment wW the incident beam ST incident on Island crystal
When the beam ST incident on Island Crystal is298 is divided into two beams TV & TX & these two beams arrive at the further surface of the glass, the beam TV wchwhich was refracted at the first surface after the usual manner, shall be again refracted entirely after the usual manner at the second surface & the beam TX wchwhich was refracted after the un-usual manner in the first surface shall be again refracted entirely after the unusual manner in the second surface, so that both these beams shall emerge out of the second surface in lines parallel to the first incident beam ST.
And if two pieces of Island Crystal be placed one after another in such manner that all the surfaces of the latter be parallel to all the corresponding surfaces of the former: the rays wchwhich are refactedrefracted after the usual manner in the first surface of the first crystal shall be refracted after the usual manner in all the following surfaces & the rays wchwhich are refracted after the unusual manner in the first surface shall be refracted after the unusual manner in all the following surfaces. And therefore same thing happens tho the surfaces of the Crystalls be any one And tho the surfaces of the glasses are any ways inclined to one another yet if provided their planes of perpendicular refraction be parallel to one another. the rays wchwhich are refracted in th
And therefore there is an original difference in the rays of light by means of wchwhich some sort of rays are in this experiment constantly refracted after the usual manner & the others sort are constantly after the unusual manner. & this difference seems to have been in the rays before their first refraction as well as before the latter refractions because it had has the For if the difference be not original but arises from new modifications tho imprest on the rays of at their first refraction, it would be altered by new modifications in the three following refractions: whereas it suffers no alteration but is constant & has the same effect upon the rays in all the refractions. ons. The unusual refraction is therefore performed by an original property of the rays. And it remains to be enquired whether the rays have not more original properties then are yet discovered.
Qu. 198. Have not the rays of light several properties in their several sides [whereby one & the same ray falling perpendicularly upon Island Crystal in one & the same angle of incidence, is is or is not refracted after the unusual manner, accordingly as this or that side of the ray is or is not turned towards the coast of unusual refraction?] several sides endued wthwith several original dispositions or properties? For if the planes of perpendicular refraction of the second glass crystal be at right angles wthwith the planes of perpendicular refraction of the first glass crystal the rays wchwhich are refracted after the usual manner in passing through the first glass crystal will be all of them refracted after the unusuall manner in passing through the second glass crystal & the rays wchwhich are refracted after the unusuall manner in the first glass passing through the first glass crystal will all of them be refracted after the usual manner in passing through the second glass crystal. And therefore there are not two sorts of rays differing in their nature from one another, one of wchwhich is constantly & in all positions refactedrefracted after the usual manner & the other constantly & in all positions after the unusuall manner. The difference between the two sorts of rays in the foregoing experiment mentioned in the 19th Question was only in the positions of the sides of the rays to the coast of unusual refraction planes of perpendicular refraction by the experimtment mentioned. For one & the same ray is here refracted sometimes after the usual & sometimes after the unusual manner according to the position wchwhich its sides have to the glasses crystalls. If the sides of yethe same ray isare posited the same way to both crystalls it is refracted after yethe same manner in them both: but if that side of yethe ray which looks towards the coast of yethe unusual refraction of yethe first crystal looks towards a coast wchwhich is 90 degrees from the plane of the perpendicular299dicular refraction of the second glass be 90 degrees from that side of the same ray wchwhich looks towards the coast of the unusual refraction of the second crystal (which may be effected by varying the position of the second crystal to the first & by consequence to yethe rays of light) the ray shall be refracted after several manners in the several crystals. There is nothing more required to determin whether the rays wchwhich fall upon the second crystal shall be refracted after the usual or after the unusual manner but to turn about thatis crystall so that the coast of this crystalls unusual refraction may be on this or that side of the ray. And therefore every ray may be considered as having four sides or quarters two of wchwhich opposite to one another incline the ray to be refracted after the unusual manner as often as either of them are turned towards the coast of the co unusual refraction, & the other two whenever either of them are turned towards the coast of unusual refraction do not incline it to be otherwise refracted then after the usual manner. The two first may therefore be called the sides of unusual refraction, & the two last the sides of usual refraction. And th since these dispositions were in the rays before their incidence on the second third & fourth surfaces of the two crystals & suffered no alteration by being refactedrefracted (so far as appears) by the refraction of the rays in their passage through those surfaces, is it not reasonable to beleive & the rays were refracted
accoringaccording by yethe same laws in the all the four surfaces, is it not reasonable to beleive that they were the were those dispositions were originally might be were originaly on the sides of it it I conclud it appears that those dispositions were in the the rays originally & suffered no alteration by the first refraction & that by means of those dispositions the rays were refracted at the same at their incidence on the first surface of the first crystal some of them after the usual & some of them after the unusual manner accordingly as their sides of usual or unusual refraction were then turned towards the coast of the unusual refraction of that crystal.
✝ ✝Every ray of light has therefore two opposite sides originally endued wthwith a property on wchwhich the unusual refraction depends & other two opposite sides not endued with that property. And it remains to be enquired whether there are not more properties of light by which the sides of the rays differ & are distinguished from one another
In explaining the difference of the sides of the rays above mentioned I have supposed that the rays fall perpendicularly on the first crystal. But if they fall obliquely on it the success is the same. Those rays wchwhich are refracted after the usual manner in the first crystal will be refracted after the unusual manner in the second crystal supposing the planes of perpendicular refraction to be at right angles wthwith one another as above, & on the contrary.
If the planes of the perpendicular refraction of the two crystalls be neither parallel nor perpendicular to one another but contein an acute angle: the two beams of light wchwhich emerge out of the first crystal will be each of them divided into two more at their incidence on the second crystal. For in this case the rays in each of the two beams will some of them have their sides of usual refraction some of them their sides of unusual refraction turned towards the coast of the unusual refraction of the second crystal.
Qu. 20. Are not the rays of light very small bodies attracting which at their en refracted by means of certain attractions wchwhich intercede And b them & the parts of pellucid bodies? For we have shewed above that bodies act upon the rays of light at a distance in reflecting refracting & inflecting them; but And by the heat wchwhich light produces it appears that light mutually acts upon bodies & in orour principles of Natural Philosophy, it appears that if the rays of light be little bodies refracted by the attraction of pellucid bodies, the sines of incidence must be to the sines of refraction in a given proportion; & the experience teaches that this is the true law rule of refraction. Also by the heat wchwhich light produces in bodies it appears ytthat the rays of light mutually act upon the parts of pellucid bodies & put them into a vibrating motion, & by the fits of easy reflexion & easy transmission wchwhich without motion cannot do & motion cannot be propagated to all distances in a instant requires an infinite force to generate it. & the vibrations excited by any ray at its entrance into a pellucid medium body seem to ever be propagated through the body to yethe further surface & there to put the ray into a fit of easy reflexion or easy transmission accordingly as they ray arrives at that surface in the middle of a vibration or in the middle between two vibrations. And by And by the unusual refractions of the rays of light in Island cCrystal the rays of light & the parts of the crystal seem to act upon one another by some power which resembles that of magnetism. For as the rays of li Iron is drawn only by magnets & magnetical bodies so the rays of light are refracted after the unusual manner only by some certain bodies namely by the particles of Island crystal & crystal of yethe rock And as a magnet has two poles in wchwhich its attractive vertue is placed so the rays of light have a vertue in in two of their two sides of unusual refraction) (wchwhich I thence call their sides not much unlike a polar vertue & in their other by means of wchwhich they are refracted after the unusual manner when either of those sides are turned towards the coast of unusual refraction, & in their other two sides they have no such vertue. And so the partsicles of Island Crystal have a vertue on one side by wchwhich they draw the rays towards the coast of unusual refraction. For if every particle of yethe crystal had the same vertue on every side they could not cause the perpendicular rays to be refracted. If light consisted only in pression propagatedted (as some suppose) it would not generat be able to generate motion & heat in the bodies wchwhich refract & reflect it. If it consisted in motion propageted pagated to all distances in an instant it would require an infinite force to generate that The rays of motion. Light moves in right lines without divergin bending towards any bending or spreading into dark the shadow beyond the bounds of those right lines in wchwhich it begins to move. But pression or motion propag cannot be propagated in a fluid without bending & spreading every way into the in right lines without bending & spreading every way from those lines into the quiescent part of the shadow in right lines in a fluid but will bend & spread every in a fluid in right lines beyond an obstacle wchwhich stops part of the motion, but will of necessity bends & spreads every way from
those lines into the quiescent medium which lies behind the obstacle The waves of water bend very much, sound bends less yet the sound of a bell may be heard beyond in a valley where a hill is between your ear & the bell sounding Bell. But the light of the sun & stars is not visible when they are behind the Moon in eclipses So Gravity tends downwards but the pressure of fluids arising from gravity tends every way with equal force & is propagated as readily & wthwith as much force through crooked passages as through streight ones. The waves of water passing by the sides of a broad obstacle bend & dilate themselves gradualy into the quiet water behind the obstacle. Sounds The undulations waves or vibrations of yethe Air wherein sounds consist bend less then yethe waves of water, yet bend manifestly. For a Bell or a Canon may be heard tho a hill be between the sounding body & the ear over a hill wchwhich intercepts the sight of yethe sounding body & sounds are propagated as readyily through crooked pipes as through streight ones. But light bends not into yethe shadow for the fixt stars by the interposition of any of yethe Planets cease to be seen & so do the parts of the Sun by the interposition of Venus Mercury or the Moon. The rays wchwhich pass by very neare the edges of any bodiyes are bent a little by some action of the body as we shewed above, but this bending is not towards but from yethe shadow & is performed only in yethe passage by yethe body. So soon as the ray is past the body it goes right on wthwithout. To explain the double refraction of Island Crystal by pression or motion propagated has not hitherto been attempted except by (to my knowledge) except by Hugenius who for ytthat end supposed two several vibrating Mediums: but when he found out the experiments mentioned in the two last preceding Questions, he confest himself at a loss. For Pressions or motions propatedpropagated f from a shining body through an uniform medium must be one must be on all sides alike; but whereas bodies propagated may have different properties in their several sides & so have the rays of light whereas by those experiments it appears that yethe rays of light have different properties in their several sides. He suspected yethe the pulses of æther might receive certain new modifications wchwhich might determin them to be propatedpropagated in this or that Medium according to yethe position of the second crystal; but what modifications those might be he could not imagin say nor think of any thing satisfactory in this point: whereas & its more difficult to imagin how such modifications can be in the rays originally if they light be nothing else then pression or motion propagated through fluids. For the refractions reflexions inflexions & colours of light depend on such properties as are in the rays originally & suffer no change by the passing of the rays through several medium's [whereas yethe Hypotheses that light suffers several changes consists in pression or motion propagated render the rays of light liable to new modifications, such as are the rotation of globuli, & the obliquity & splitting of pulses, & the propagation of motion from one single medium to two others, &And by such new modifications the authors of those Hypotheses place the difference of colours & yethe double refractions of Island Crystall whereas the refractio colours of light depend on original & immutable properties of the rays labour endeavour to explain the phænomena of colours & refractions.] & therefore all Hypotheses are to be laid aside in wchwhich those phænomena are derived from new modifationsmodifications of yethe rays.
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Qu. 19. Are not all Hypotheses erroneous which have hitherto been invented for explaining the phenomena of light by new modifications of the rays. For all those phenomena of light hitherto explained by them hitherto known (viz. the different refrangibility & inflexions reflexibility & inflexibility of its rays & all the diversity of colours & the unusual refraction of Island Crystal) depend not upon new modifications, as has been supposed but upon the original & unchangeable properties of the rays.
Qu. 20. Are not all Hypotheses erroneous in wchwhich light is supposed to consist in pression or motion propagated through a fluid Medium? For in all these Hypothese the phænomena of light have been hitherto explained by supposing that they arise from new modifications of the rays: wchwhich is an erroneous supposition.
If light consisted only in pression propagated without actual motionit would not be able to agitate & heat the bodies wchwhich refract & reflect it. If it consisted in motion propagated to all distances in an instant, it would require an infinite force every moment in every shining particle to generate that motion. And if it consisted in either pression or motion propagated or either in an instant or in time it would bend into the shadow. For pression or motion cannot be propagated in a fluid in right lines beyond an obstacle wchwhich stops part of the motion, but will bends & spreads every way into the quiescent medium wchwhich lyes beyond the obstacle. Gravity tends downwards, but the pressure of water arising from Gravity tends every way with equal force & is propagated as readily & with as much force through crooked passages as through streight ones. The waves on the surface of water passing by the sides of a broad obstacle bend & dilate themselves every way gradualy into the quiet water behind the obstacle. The waves pulses or vibrations of the Air wherein sounds consist bend manifestly, tho not so much as the waves of water. For a bBell or a Canon may be heard beyond a hill wchwhich intercepts the sight of the sounding body, & sounds are propagated as readily through crooked pipes as through streight ones. But light is never known to follow crooked passages nor to bend into the shadow. For the fixt stars by the interposition of any of the Planets cease to be seen, & so do the parts of yethe Sun by the interposition of the Moon Mercury or Venus. The rays wchwhich pass very near to the edges of any body are bent a little by the action of the body as we shewed above, but this bending is not towards but from the shadow & is performed only in the passage of the ray by the body & at a very small distance from it.. So soon as the ray is past the body, it goes right on.
To explain the unusual refraction of Island Crystal by pression or motion propagated has not hitherto been attempted (to my knowledge) except by Hugenius who for that end supposed two several vibrating Mediums within that Crystal. But when he tried the refractions in two several pieces o successive pieces of that crystal & found them such as is mentioned above: he confessed himself at a301 a loss for explaining them. For pressions or motions propagated from a shining body through an uniform Medium must be on all sides alike: whereas by those experiments it appears that the rays of light have different properties in their different sides. He suppos suspected that the pulses of Æther in passing through the first crystal might receive certain new modifications wchwhich might determin them to be propagated in this or that Medium within the second crystal according to the position of that crystal, but what modifications those might be he could not say nor think of any thing satisfactory in that point.Mais pour dire comment cela se fait, je n'ay rien trouvé jusqu'ici qui me satisfasse. C.H. De la lumiere. c. 5. p 91. And if had known that yethe unusual refraction depends not on new modifications but on the original & unchangeable dispositions of the rays, he would have found it as difficult to explain how those dispositions which he supposed to be imprest on the rays by the first Crystal could be in them before their incidence on that Crystal, & in general how all rays emitted by shining bodies can have those dispositions in them from the beginning. To me at least this seems inexplicable if light be nothing else then motion pression or motion propagated through Æther.
And it is as difficult to explain by these Hypotheses how rays can be alternately in fits of easy reflexion & easy transmission; unless perhaps one might suppose that there are in all space two ethereal vibrating Mediums & that the vibrations of one of them constitute light & that the vibrations of the other being swifter, as often as they overtake the vibrations of the first, put them into those fits. But to allow two æthers where we have no evidence for so much as one, to suppose that two æthers may be together in all spaces without mixing with one another so as to become one Medium & to suppose also that they may have distinct vibrations without making two sorts of light, are difficulties wchwhich I cannot get over. And that there are no such fluid Mediums I gather by the following argument regular & very lasting motions of Planets & Comets through the heavens in all manner of positions: For thence it is manifest that the heavens are void of all sensible resistance, & by consequence of all sensible matter.
For the resisting power of fluid Mediums arises partly from the attrition of the parts of the Medium & partly from the Vis inertiæ of the matter. That part of the resistance of a spherical body wchwhich arises from the attrition of the parts of the Medium is as the factum of the diameter or& the velocity of the spherical body very nearly & that part of the resistance wchwhich arises from the Vis inertiæ of the matter is as the square of that factum. And by this means difference the two sorts of resistance may be distinguished from one another in any Medium & being distinguished it will be found that almost all the resistance of bodies of a competent magnitude moveing in Air Water & Quicksilver & such like fluids with a competent velocity arises from the Vis inertiæ of the parts of the fluid. For this I have found true by Experiments made with Pendulums. And hence I conclude that all æther & all subtile Mediums whatever which are as dense as air water or quicksilver, have almost as great a resisting power as the fluids of air water or quicksilver to wchwhich they are equal in density. where supposing that bodies of a competent magnitude move in those fluids with a competent velocity, as in the experiments of the pendulums.
For Now that part of the resistanceing wchwhich arises from power of any Medium wchwhich arises from the tenacity or attrition of the parts of the Medium may be diminished by dividing the
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meet before they come into the brain, but the Optick Nerves of such animals as do not look the same way with both eyes (ias of Fishes & the Chameleon) do not meet if I am rightly informed
Qu. 16. Are not When a man in the dark presses either corner of his eye with his finger & turns his eye away from his finger, he will see a circle of colours like those in the feather of a Peacocks taile?. Do not these colours arise from such motions excited in the bottom of yethe eye by the pressure of the finger, as at other times are excited inthere the bottom of the eye by light for causing vision?
When I made these Observations I designed to repeat most of them with more care & exactness & to make some others new ones for determining the manner how the rays of light are bent in their passages by bodies for making these f fringes of colours wthwith yethe dark lines between them: but but I was then interrupted & cannot now think of taking these things into further consideration. And since I have have not finished this part of my designe &I shall conclude with proposing only some Quæres in ortder to a further search to be made by others in these matters by others. [who may take these things into consideration]
Quære 1. Do not Bodies act upon light at a distance & by their action bend its rays & is not this action strongest at yethe least distance. ☉1 B. Are not &c ☉ 1 B. Are not the rays of light in passing by the edges & sides of bodies bent several times backwards, & forwards with a motion like that of an Eele.
2 Are not the rays more or less flexible accordingly as they are more or less refrangible, Do not the rays wchwhich differ in refrangibility differ also in flexibility & are they not & are they not & by their different inflexions made at equall distances from yethe bodies are they not separated from one another so as after separation to make the colours in the three fringes of colours above described. And after what manner are they inflected to make those fringes.
3 Do not the rays of light wchwhich fall upon bodies & are reflected or refracted begin to bend before they arive at yethe bodies, & are they not reflected refracted & inflected by one & yethe same Principle acting variously in various circumstances.
4 Do not light & bodies act mutually upon one another, that is to say bodies upon light in emitting reflecting refracting & inflecting it, & light mutually478ally upon bodies for heating them & putting their parts into a vibrating motion wherein heat consists. And do not black bodies conceive heat more easily from light then those ‡‡ A) 4. And Do not black bodies conceive heat more easily from light then those of other colours do, by reason that yethe light falling on them is not reflected back but enters yethe bodies & is often reflected & refracted within them before it be stifled & lost. And is not the greatness or vigour the action between light & sulphureous bodies observed above one reason why sulphureous bodies conceived heat & burn take fire more readily & burn more vehemently then other bodies do?
5 Do not all fixt bodies when heated beyond a certain degree emit light by the vibrating motion of their parts.
6 Is not fire a body heated so hot as to emit light copiously. For what else is a red hot iron or a red hot stone then fire & what else is a burning coale then red hot wood [whose heat is preserved by the actions of an acid spirit in the air acting upon by dissolving the wood
7 Is not flame a vapour fume or exhalation heated red hot that is so hot as to shine For bodies do not do not flame wchwhich do not emit a copious fume.
8 Are not the sun & fixt stars great earths vehemently hot whose heat is conserved by the mutuall action & reaction between them & the light wchwhich they emit & whose parts are kept from fuming away by the vast weight of the Atmospheres incumbent upon them.
9 Do not the rays of light in falling upon the Tunica retina bottom of the eye excite vibrations in yethe Tunica retina wchwhich vibrations being propagated along the solid fibres of yethe Optick Nerves into the brain cause the sense of seeing. And are not the vibrations made by several sorts of rays * * For since dense bodies conserve their heat a long time & the densest bodies conserve their heat the longest, the vibrations of their parts are of a lasting nature & therefore may be propagated along solid fibres of uniform dense matter to a great distance for conveying into the brain the impressions made upon all the Organs of sense. For that motion wchwhich can continue long in any one part one & yethe same part of a body can be propagated a long way from one part to another supposing the body homogeneal so that yethe motion may not be reflected refracted & interrupted or disordered by the any uneavenness of the body. 10 And Do not several sorts of rays make vibrations of several bignesses, the wchwhich according to their several bignesses excite sensations of several colours much after the manner that several the vibrations of yethe air according to their several bignesses exiteexcite sensations of several sounds? And particularly do not the most refrangible rays excite the shortest vibrations for making a sensation of deep violet, the least refrangible the largest for making a sensation of deep red & the several intermediate sorts of rays vibrations of several intermediate bignesses to make sensations of the several intermediate colours?
11 May not the harmony & discord of colours arise from the proportions of the vibrations the like and oth propagated through the optic nerves into the brain as the harmony & discord of sounds arises from the proportions of yethe vibrations of yethe air. For some colours are agreable as theose colours of gold & Indigo & others disagree.
112. May Are not the species of objects seen wthwith both eyes united where the Optick nerves meet before they come into the brain: For the fibres on the right side of both Nerves uniting there & after union going thence into yethe brain in the nerve wchwhich is on the right side of the head & the fibres on the left side of both nerves uniting in the same place & after union going into the brain in the nerve wchwhich is on the left side of the head into yethe brain & these two nerves meeting again in the brain in such a manner that their fibres make but one intire species half of wchwhich on yethe right side of yethe sensorium & comes from yethe right side of both eyes & the other half of wchwhich on yethe left side of yethe sensorium comes from yethe left side of both eyes? For the optic nerves of such animals as look the same way with both eyes (as of Men, Doggs, Sheep, Oxen) meet before they go into the brain, but the optic nerves of such animals as do not look the same way wthwith both eyes (as of Fishes & the Chameleon) do not meet if I am rightly informed.
7B. Is not the
7B. Is not the greatness of the action between light & sulphureous bodies observed above, one reason why sulphureous bodies conceive heat & burn more readily & more vehemently then other bodies do.