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receiving the Impreflion of the greater Quantity of Spirit bf Nitre alone, is dijfolved thereby. But the Experiment cannot be inverted, i. e. Aqua Regia cannot begin with dijjblving Silver lightly firtt, and afterwards difjblve Gold- by reafon Spirit of Nitre does not hinder Spirit of Salt from acting on Gold; as Spirit of Salt does Spirit of Nitre from acting on Silver. See Gold, and Silver.

2)ijjblvents are ufually call'd by the Chymifts Men- ftrtlftms. See Menstruum.

Univerfal Dissolvent. See AlcAhest.

DISSOLUTION, in Phy licks, a Difcontinuation, orAna- lyfis of the Structure of a mixt Body ; whereby, what was one, and contiguous, is divided into little Parts, either homo- oeneous, or heterogeneous.

Z)iJfoIution, then, is a general Name for all Reductions of concrete Bodies into, their fmalleft Parts, without any re- gard either to Solidity, or Pluidity : Tho* in the ufual Ac- ceptation of the Word among Authors, it is reft rained to the Reduction of folid Bodies into a State of Fluidity; which is more properly expreffed by Solution^ as a Branch oftDif- folut'ion. See Solution.

According to the Opinion of Fr. 1*ertius de Zanis, now confirmed by that of the Learned Soerfoaave, in his Chy- miftry, the Power, or Faculty of Z)iJfolviug t is lodged in Fire alone. See Fire.

Other Fluids, commonly fuppofed Qiffolvents, only pro- duce their Effect by means of the fiery Sjicidi they abound withal. Even Air, which is judg'd a powerful Menfttuum, owes all its Force to the Rays of Light diffufed therein. See Air, and Menstruum.

Sir Ifaac Newton accounts for all Diffolutions, and the feveral Phenomena thereof, from the great Principle of At- traction ; And, in Effect, the Phenomena of IHfjohition furni/h a great Part of the Arguments, and Considerations, whereby he proves the Reality of that Principle. See At- traction.

A. Specimen of that great Author's Way of Philofophizing on the Subject of tDijjfolution take as follows :

When Salt of Tartar diffolves by lying in a morft Place, is not this done by an Attraction between the Particles of the Salt of Tartar, and thofe of the Water, which float in the Air in Form of Vapours ? And why does not common Salt, or Salt-petre, or Vitriol do the like ; but for Want offuch an Attraction. And when Aqua forth, or Spirit of Vitriol, pour'd on Srccl-filings, dijfolves the Filings, with a great IJeat, and Ebullition; is not this Heat and Ebullition effected by a violent Motion of the Parts ? And does not that Motion argue, that the acid Parts of the Liquor ruih towards the Parts of the Metal with Violence, and run forcibly into its Pores ; till getting between the out- moft Particles, and the main Mais of Metal, they loofen Water ? When a Solution of Iron in Aqua forth diffolves Lapis Caltlminaris, and lets go the Iron ; Or a Solution of Copper diffolves Iron immerfed in, and lets go the Copper ; Or a Solution of Mercury in Aquafortis pour'd on Iron, Copper, Tin, or Lead, diffolves the Metal, and lets go the Mercury ; dees not this argue, that the acid Particles "of the Aquafortis are attracted mere ifrongly by the Lapis Cala- ptinai'is, than by Iron ; by Iron than by Copper ; by Copper than by Silver; and by Iron, Copper, Tin, and Lead, than by Mercury ? And is it not for the fame reafon, that Iron re- quires more Aqua fortis to diffolve it, than Copper; and Copper more than the other Metals ; And that of all Me- tals Iron is dijfolved moll- eafily, and is molt apt to ruft ; and next after Iron, Copper ? When Aquafortis diflblves Silver, and not Gold; and Aqua Regia diffolves Gold, and not Silver ; may it not be {aid, that Aqua fortis is fubtile enough to penetrate the Pores of Gold as well as of Silver, but wants the attractive Force to give it Entrance ; and the fame of Aqua Regia, and Silver? And when Metals arc dijfolved in acid Menfirttums, and the Acids in Con- junction with the Metal, act after a different Manner ; So as that the Tafte of the Compound is milder than that of the Simples, and fometimes a fwect one ; is it not becaufe the Acids adhere to the Metallic Particles, and thereby lofe much of their Activity? And if the Acid be in too imall a Pro- portion to make the Compound diffoluble in Water ; will it not, by adhering fkongly to the Metal, become unaaive, and lofe its Taffc ; and the Compound become a taff clefs Earth ? For fuch Things as are not diffoluble by the Moiffure of the Tongue, are infipid. Newt. Opt. in Calce.
 * em therefrom, and fet 'em at Liberty to float off into the

Monfr. Geoffrey furni/hes fome curious Experiments on Cold 2)ijfoltttions, in the Memoires de P Academic Royale des Sciences ; which have been translated in the 'Phiiofo- phicalTranf Rations : 'Tis nothing furprizing, that a fimplc iDijjolution fhould be cold ; that common Water, for In- ftance, wherein Sea-Salt, or Sal Ammoniac, or Vitriol, has been caff, mould become the colder, by the Mixture offuch Salts; It being obvious, that the Salts, being of themfelves deflkute of Motion, and coming to ihare that which the

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Fluidity gives the Water muft diminifh it, when they be- come intimately mad therewith by D,ff olmim Anrl it is generally agreed among Philofophers, that Heat is a Mo- tion andColdaCeffation or at leaft a Diminution of Motion. W > no ;, w » h ^" dul g thls general Principle ; ' tis n0 great Wonder all Diffolutiom are not Cold, as thofe are of all vo- latile Alcalies in common Water ; But that fome are Hot as thofe of all fix'd Alcalies. The Difference may be ac- counted for hence, that all fix'd Alcalies having been cal- cined by a vehement Fire, they have imprifon'd, and re- tain' d in their Pores fome of the Particles thereof.

But it is furprizing, that Xliffblutions accompanied with Fermentation, i. e. where the Matters boil, and fwell, and that with a great Noife, fhould he cold, and make the Ther- mometer fall, when immerged therein.

3 his Coldnefs, with fo considerable an Augmentation of Motion, is fomewhat extraordinary. But this is not all : For, ot thefe cold Fermentations, there are fome that emit hot\apours. Thus it is, with a Mixture of Oil of Vitriol, and Sal Ammoniac ; for a Thermometer being plunged in the Mixture, and another a little higher, to receive only the Fumes thereof ■ the firft Thermometer is feen to fall very Jiaftily, through the Coldnefs of the Fermentation, and the latter to rife through the Heat of the Vapours. Monfr. Geoffrey adds an Experiment, Ihcwing that cold Water is render d ftill colder for a few Moments, by throwing a large Quantity ot live Coals therein.

Dissolution, in Chymiftry, Pharmacy, &c. the Re- duction of a compact, hard, or folid Body into a fluid State by the Action of fome fluid Menftrimm, or 2)iffolvent. See Menstruum, and Dissolvent.

Dr. Quincy gives us a Mechanical Account of Diffblvtioi? in the Inflance of Salt dijfolved in Water, which is the moft fimple Operation that tails under this Head. This Mo- tion he afcribes to that attraflive Force, which is fo very extenfive in Natural Philofophy, that there is no Kind of Matter, but what is under its Influence. It may be obfer- ved, that the Corpufcles of Salts, which are the moft Am- ple of any, are withal very minute, and for their Bulk very folid, and, therefore, exert a very ftrong attractive Force, which, ceteris 'Paribus, is proportional to the Quan- tity of Matter. Hence it comes to pafs, that the Particles of Water are more ftrongly attracted by the faline Particles than they are by one another: The Particles of Water' therefore, cohering but loofely, and being eafily moveable* approach the Corpufcles of Salts, and run, as it were, into their Embraces ; and the Motion of them is quicker, or flower, according to their lefs, or greater Diftances ; the at- traflive Force in all Bodies being ftrongeft, at the Point of Contact. Therefore, if Salt be thrown into the middle of a Difli full of Water, we ihall find the aqueous Particles which are in the middle of the Dilh, fliarp, and pungent to the Tafte ; but the Water upon the Sides of the Veflci almoft infipid ; fo that, when fuch a Motion once arifes the aqueous Particles are carried with the fame Force to- wards the Salts ; and the Moment of them is to be efti- mafed from the Ratio of their Weight, and Celerity, con- junctly. By the Force of this Impulfe, they open to them- felves a Paffage into the Pores of the Salts, which are very numerous ; and at length break, and divide their Tex- ture, that all Cohefion of their Parts is deftroved : Here- upon, being feparatcd, and removed to a convenient Diflance from one another, they are difperfed, and float here and there about the Water. See Fusion, Salt, Solution £SV

Dissolution of Metals, £?c. by Fire, is particularly call'd Fvfion. See Fusion. '

Dissolution of the Blood, is an Affection of that Humor dire&ly oppofite to Coagulation. See Coaoulation.

The'fDtJfoltuion is fuch a Comminution of the fibrous Parts of the Blood, as indifpofes it for that Separation of the Craf- famentum from the ferous Part, which always enflres in healthy Blood on its cooling out of the Body. See Blood.

This Diffolution is frequently the Confequence of malig- nant, and peftilential Fevers, and fliews it felf in 'Petechia or PurpleSpots; alfo of certain Poifons, particularly the Bites of venomous Beads, iSc. See Fever, Poison, (5c.

Dissolution of Parliament. See Parliament, and Prorogation.

DISSONANCE, or DISCORD, in Mufic,. a falfe Ccn- fonance, or Concord. See Concord, and Consonance.

A TSiJJhiance is properly the Re'ult of a Mixture, or Meeting of two Sounds, which are difagreeable to the Ear: Such are Xlitones, Tritones, Falfe Fifth, 'Redundant Fourth, Seventh, &c.

Z)iJ]bnances are ufed in Mufic, and have a good Effect therein; tho' it be only by Accident. See Discord.

DISSUASION, in Rheroric. See Persuasion.

DISSYLLABLE, a Word of two Syllables ; as Fortune, Lament, &c. See Foot.

The Spondee, Trochee, Jambus, and Py.r'lichius, are dif~ fyllabic Feet. See Si'Ondee.

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