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pofing the fame Denfity to remain in the Body, and the Diftance of the Corpufcle to continue the lame.
For fince the attractive Powers of Particles are diflus'd only through the fmalleft Spaces; 'tis manifeft that the remoter Parts at CD and £ contribute nothing towards attracting the Cor- pufcle^: And therefore the Corpufcle will be attracted with the fame Force towards B, whether thefe Parts remain or be take taken away; or, laftly, whether others be added to them.
Hence, Particles will have different attractive Forces, accord- ding to their different Structure and Compolitionj thus a Par- ticle perforated will not attract fo ftrongly as if entire. So, a- gain, the different Figures into which a Particle is form'd, will occafion a diverhty of Power; Thus a Sphere will attraCt more than a Cone, Cylinder, &c.
X. Suppofe a Body of fuch a Texture as that the Particles of the laft Compofition, by an external Force, fuch as a Weight comprefling them, or an Impulfe given by another Body, may be a little removed from their original Contact, but fb as not to acquire new ones ; the Particles by their attractive Force rend- in* to one anotherj will foon return to their original Contacts. — But when the fame Contacts and Pofitions of the Particles which compofe any Body, return ; the fame Figure of the Body will alfo be reftor'd : And therefore Bodies which have loft cheir ori- ginal Figures, may recover them by Attraction
Hence appears the Caufe of Elaficity. — For, where the contigu- ous Particles of a Body have by any external Violence been fore'd from their former Points of Contact, to extremely fmall Di- fiances; as foon as that Force is taken off, the feparated Parti- cles mufl return to their former Contact : By which means the Body will relume its Figure, &c. See Elasticity.
XI. But if the Texture of a Body be fuch that the Particles by an impreffed Force being remov'd from their Contacts, come immediately into others of the fame Degree, that Body cannot reftore it felf to its original Figure.
Hence we understand what Texture that is •wherein the Softnejs of Bodies conjifis. See Softness.
XII- The Bulk of a Body heavier than Water, may be fo far diminifh'd, that it mall remain fufpended in Water, without de- scending by its own Gravity. See Specific Gravity.
Hence it appears why faline, metallick, and other fuch-like Particles, when redue'd to fmall Dimenlions, are fufpended in their Menftruums. See Menstruum.
XIII. Greater Bodies approach one another with a lefs Velo- city than fmaller.— For the Force with which two Bodies A and
B approach, refides only in the nearefl Particles ;
OA. the more remote having nothing to do therein. No greater Force, therefore, will be apply 'd to move the Bodies A and B, than to move the Par- ticles c and d; but the Velocities of Bodies mov'd Qby the fame Force are in a reciprocal Ratio of the Bodies: Wherefore the Velocity with which the Body A tends towards £, is to the Velocity with which the Particle i detach'd from the Body would Ji tend towards the fame B, as the Particle c is to the Body B ; confequently the Velocity of the Body A is much Itfs than wou'd be the Velocity of the Particle c detach'd from the Body.
Hence it is that the Motion of large Bodies is naturally fo flow and languid, that an ambient Fluid and other circumjacent Bo- dies generally retard them ; whilft the lefler go on more briskly, and produce a greater number of Effects: So much greater is the attractive Energy fa fmaller Bodies than in the larger. — Hence again appears the Reafon of that chymical Axiom ; Saks don't aCt till they are dijfo'v'd.
XIV. If a Corpufcle placed in a Fluid be equally attracted e- very way by the circumambient Particles, no Motion of the Corpufcle will enfue. — But if it be attracted by fome Particles more than others, it will tend to that part where the Attraction is the greateft; and the Motion produe'd will correfpond to the Inequality of the Attraction-) viz. the greater the Inequality, the greater the Motion, and vice verfa.
XV. Corpufcles floating in a Fluid, and attracting each other more than the Particles of the Fluid that lie between them, will force away the Particles of the Fluid, and rufh to one ano- ther with a Force equal to that by which their mutual Attracti- on exceeds that of the Particles of the Fluid.
XVI. If a Body be irnmcrged in a Fluid whofe Parts more ftrongly attract the Particles of the Body than they do one ano- ther ; and if there be a number of Pores or Interfaces in the Body pervious to the Particles of the Fluid ; the Fluid will im- mediately diffufe itfelf through thofe Pores. And if the Con- nexion of the Parts of the Body be not fo ftrong, but that it may be overcome by the Force of the Particles rufhing within it; there will be a Diffolution of the Body. See Disso- lution.
Hence, for a Menitruum to be able to difTolveany given Bo- dy, there are three things requir'd.— 1°. That the Parts of the Body attract the Particles of the Menitruum more ftrongly j than thefe attract each other- z\ 7^ the £ody have, Ports or In-
terftices open and pervious to the Particles of the Menftruum.' 3°. That the Cohefion of the Particles which conftitute the Bo- dy, be not itrong enough to refift the Irruption of the Particles of the Menftruum. See Menstruum.
XVII. Salts are Bodies endued with a great attractive Force. though among them are interfperfed many Interfaces, which lie open to the Particles of Water; thefe are therefore ftrongly at- tracted by thofe faline Particles, fo that they forcibly ruiti into them, feparate their Contacts, and dilTolve the Contexture of the Salts. See Salt.
XVIII- If the Corpufcles be more attracted by the Particles of the Fluid than by each other; they will recede from each ci- ther, and be dirFiis'd through the whole Fluid.
Thus, if a little Salt be diflolved in a deal of Water, the Par- ticles of the Salt, though fpecifically heavier than Water, will e- venly diffufe themfelves through the whole Water , fo as to make it as Saline at Top as Bottom- — Does not this imply that the Parts of the Salt have a centrifugal, or repulflve Force, by which they fiy from one another^ or rather, that they attract the Water more ftrongly thin they do one another ? For as all things afcend in Water which are lefs attracted than Water by the Gravity of the Earth, fo all the Particles of Salt floating in Wa- ter, which are lefs attracted by any Particle of Salt, than Wa- ter is, muft recede from the Particle, and give way to the mora attracted Water- Newt. Opt. p, 363.
XIX. Corpufcles, or little Bodies fwimming in a Fluid, and tending towards each other j if they be fuppos'd ehftick, will fly back again after their Congrefs, till ftriking on other Corpufcles, they be again reflected towards the firitj whence will arife innumerable ether Conflicts with other Corpufcles, and a conti- nued Series of Percuflions and Reboundings.— But, by the at- tractive Power, the Velocity of fuch Corpufcles will be continu- ally increafed; fo that the inteftine Motion of the Parts will at length become evident to Strife. See Intestine Motion.
Add, that in proportion, as the Corpufcles attraCt each other with a greater or lefs Force, and as their Eiafticity is in a greater or lefs Degree, their Motions v\ ill be different, and become fen- tible at various Times, and in various Degrees.
XX- If Corpufcles that attrad each other happen mutually to touch, there will not arife any Motion, becaufe they cannot come nearer. If they be placed at a very little Diftance from each other, a Motion will arife; but if further remov'd, the Force wherewith they attraCt each other, will not exceed that where- with they attraCt the Particles of the intermediate Fluid, and therefore no Motion will be produced.
On thefe Principles depend all the Phenomena of Fermentation and Ebullition. See Fermentation and Ebullition.
Hence appears the Reafon why Oil of Vitriol, when a little Water is poured on it, works and grows hot : For, the faline Corpufcles are a little disjoin'd from their mutual Contact, by the infus'd Water ; whence, as they attract each other more ftrongly than they do the Parades of Water, and as they are not equally attracted on every fide, there muft of neceflity arife a Motion. See Vitriol.
Hence alfo appears the Reafon of that uncommon Ebullition occaiion'd by adding Steel-filings to the fcrefaid Mixture. For the Particles of Steel are extremely elaftick ; whence there muft arife a very ftrong Reflection.
Hence alfo -we fee the Reafon why fetne Menftruums aCt mere flrongly, anddijfoh-e Bodies fomer, when diluted with Water.
XXI. If Corpufcles mutually attracting each other have no elaftick Power, they will not be reflected back from each other, but will form Congeries, or little Maflesj whence a Coagulum will arife. See Coagulation.
If the Gravity of the Particles thus amafs'd, exceed the Gra- vity of the Fluid, a Precipitation wilt fucceed. — Precipitation may alio arife from an Inereafe or Diminution of the Gravity of the Menftruum wherein the Corpufcles are immerg'd. See Preci- pitation.
XXII. If Corpufcles fwimming in a Fluid, and mutually at- trailing each other, have fuch a Figure, as that in feme given Parts they have a greater attractive Power than in others, and their Contact greater in thofe Parrs than in others ; thofe Cor- pufcles will unite into Bodies with given Figures; and thence will arife Cryftaltization. See Crystallization.
Particles irnmcrged in a Fluid moved with a fwift or a flow progreflive Motion, will attract each other in the fame Manner as if the Fluid were at reft ; but if all the Parts of the Fluid do not move equally, the Attractions will be difturbed.
Hence it is that Salts will not cryftallize till the Water where- in they are diflolved is cold.
XXIV. If between two Particles of a Fluid there happen to be a Corpufcle whofe two oppoflte Sides have a ftrong attractive Power, that intermediate Corpufcle will agglutinate or faften the Particles of the Fluid to it felf.— And fevcral fuch Corpufcles diftus'd through the Fluid, will fix all its Particles into a firm Bo- dy i and the Fluid will be froze or redue'd into Ice. See Free- zing.
XXV- If a Body emit a great Quantity of Effluvia whofe at~ tractive Powers are very ftrong; as thofe Effluvia approach any other very light Body, their attractive Powers will overcome the Gravity of that Eody 3 and the Effluvia will draw it towards them- felves :
