Page:Cyclopaedia, Chambers - Volume 2.djvu/484

 PRE

(8*1)

PRE

of Cohefion is alfo weaken 'd, fo as to become unable any longer to fuflain the Bodies; fo Hydrometers, which are eafily fuftainM in Water, upon pouring in a good deal of any burning Spirits fink to the bottom of the Glafs.

And this agrees not only with the Laws of Mechanics, but with Experiments : Thus Spirit of Sal Armoniac does very plentifully precipitate the Filings of Metals, diflblved in acid Menitruums 3 tho* it be abundantly lighter than any of them.

' The fame thing is done quicker by Spiric of Wine, whofe Gravity is known to be almoft the leafi of any Liquor.

By this Spirit alfo, all Salts, which are fufpended in W-ater, are precipitated, and fo unite into Cryitals. So if you drop in diililied Vinegar, the Drols of Antimony dif- fufed in Water, it falls to the bottom, and affords the Gol- den Sulphur.

After the fame manner, Water, Vinegar, $£>c. make a Precipitation from Acids, tho' more fparingly : Nay, A- cids themfclves being pour'd upon others which are hea- vier, will precipitate whatever is iwimming in them. Thus Spirit of Salt precipitates ei'ther Lead, Copper, or Tin, diffolv'd in Oil of Vitriol : fo little need is there of Alka- lies in this Bufinefs, tho' the Chymifts have unanimoufly contended for them as abfolutcly neceffary.

In the id Cafe, Treciptation will fucceed by the Addi- tion of a heavier Liquor to the Menttruum. For the Parti- cles of this Liquor, what with their Weight, and what with the Impetus they acquire in their Defcenr, carry down and fink all the folid Corpufcles they meet with in their way ; fo that the Corpufcles being thus forced down, and kept there by this adventitious Liquor, cannot mount up into their former Situation.

To try the Truth of this Reafoning by Experiments 5 not only acid Spirits, but even mere Water, will be found to precipitate Tinctures of Vegetables extracted by Spi- rit of Wine : And the very fame Tinctures, extracted with Water, or Wine, are precipitated rery copioufly by acid Spirits, which are heavier.

Metals, when diffolved in Spirit of Sal Armoniac, are precipitated with Oil of Vitriol, or Spiric of Nitre. When fufpended in Aqua Fortis, they are precipitated with Oil of "Vitriol, or Bezoartic Spirit of Nitre.

- As to Bodies fufpended by means of their Union with 0- ther lighter ones : This is properly the Cafe of diffolved Metals; and to this may the lait Cafe of 'Precipitation be reduced. Here, the Particles of a Metal being feparated by a Diffolvent, and rendred imperceptible by their ex- treme Littlenefs, only float, becaufe united to very light Particles of the acid Spirit, which keeps them fufpended : Tho* the great Surface they have, both on account of their Smallnefs, and of their Union with the Acids, frequently contribute to the Effect.

Now, as they are in a forced Equilibrium with the Fluid wherein they fwim ; and as the Caufes that fuflain them, ore only accidental ; they mull of courfe be precipitated to the bottom, when the Acid or Menllruum abandons them ; from whatever Caufe it be : It is even fometimes fuffi- cient, that the Quantity of the Fluid, wherein they are fuf- tain'd, be diminiflYd. For then, feveral of the Metallic Particles, tho dill join M to their Acid, coming to meet, and unite, affurnea fmallcr Surface, with regard to their Mafs 5 thus, being no longer held up by the Largenefs of their Surfaces, they fubfide to the bottom.

When the Menftruum abandons a diffolved Body; if that Body be lighter than the Menftruum, the contrary to a "Precipitation willenfue, i.e. the Body will rife.- Thus Camphor being mixed in Oil of Olives, and the whole dif- folved, the Camphor rifes firtt, £5?c.

If it happen that the Particles, when abandoned by the Diffolvent, are equally heavy with the fuftaining Fluid ; they will neither rife nor fall; only feveral of them now re-uniting, form little Mafles, fufheient to fpoil rheLimpid- nefs and'Tranfparency of the Fluid ; as is the Cafe in Re- fins diflblved in Spirit of Wine, and Water pour'd over them : where the Water uniting clofely with the Spirit of Wine, makes it let go the greateft part of the rcfinous Par- ticles.

Thus is effected what we call an Imperfect Precipita- tion; which, in reality, is no more than a Difpofition to precipitate. , . ,

If in this Cafe, the Aqueous Particles of the Fluid be hid, and as it were, abforb'd among the grofs Molecule of the diffolved Matter; it forms what they call a Coagulum. See Coagulation.

Sometimes, when the Liquors are pour'd on one ano- ther, the Salts with which they abound, being put into Motion, by their attractive Force, they run mutually to em- brace one another ; and becaufe they don't recoil far back after the Congrefs, they are at length fo united, as to be- come like a Solid, there beins very little Phlegm remain- ing, as is very obfervabie in Tartarian Vitrioktmn.

In thefe Experiments there happens fuch a Conflict and EfFervefccnce, as evaporates almott all the Moifture, with which the Salts are diluted. And upon this depends the Rationale of Chymical Coagulation, a thing of very great confequence in the Bufinefs of Precipitation. Nor can we account for Oil of Tartar's precipitating Bodies diffolv'd in Acids, any otherwife than from its making a kind of Co- agilllira with thefe Corpufcles, and thereby becoming too heavy for, and exceeding the Tenacity of, the Menftruum. Such are the general Principles of Precipitation PRECEPTORY, Prjeceptoria, or Commandry, a kind of Benefice held by the more Eminent among the antient Knights-Templars; who were erearedby theGrand- Mafter, with the Title of Pr<gccptores Te?Kpli t i.e. Maflcrs of the Temple. See Te mpl a r.

Stephens de Jurifd. lib. 4. fays, the Prgceptories were only a kind of Cells, all fubordinate to their principal Man- fion, the 'Temple in London. See Temple.

Of thefe Pneceptories, 2)ugdalc fay?, he finds fixteen recorded, as antiently belonging to the Templars in Eng- land ; viz. Creffwg Temple, Saljhal, Shangey, Ne-ivland t Teveland, Witham, Temple-Sruere, Will'mgton, Rotbeley, Ovenington, Temple Comb, Trebigh, Ribftane, Mount St. John, Temple-Ne-ztftim, and Temple Hurft. But there were more. See Commandr.it.

PRECIPUT, in Jurifprudence, an Advantage belonging to any one, in a thing to be divided ; or a Portion taken off, and fet by, in his favour, e'er the Divifion be made.

In noble Partition, the Eldeft has always the principal Fief, or Mannor, for his Preciput.

The Preciput coincides with the Right of Primogeni- ture. See Pri mogeniture.

The Word is furm'd from the Latin Prtfcipims, Chief, Principal.

PRECISION, Prjecisio, in the Schools, the fame with AbflraQion. See Abstraction.

PRECONISATION, aPropofition or Declaration, which the Cardinal Patron makes in the Confiltory at Rome., of a Perfon nominated by fome Prince to a Prelature ; by vir- tue of Letters, whereof he is the Bearer: which the Pope complying with, gives his Collation.

The Date of the Bulls is difpatchM on the fame Day with the Freconifation.

PRECONTRACT, a Contract made before, or prior to another; chiefly ufed in relation to Marriages. See Contract.

PRECURSOR, Precursor, Fore-runner, in Theolo- gy, a Perfon who goes before any one to notify his com- ing.

The Term is peculiarly apply'd to St. John Saptift, who is ftiled the Precurfor of Jefus Chrift, from what is faid of him by St. Luke, Thou, Child, Jbalt go before -the face of the Lord, to prepare his -zvay.

PREDECESSOR, a Perfon who has preceded another in the fame Office, or Employ.

FREDESTINARIAN, a Perfon who adheres to the Doctrine of abfolute Predeftination. See Predestina- tion.

Si. Auguflin is look'd on as the Founder of the Seel of Predrfiinarians ; he being the firft of the Fathers that feems to have after ted the Doctrine in fuch exprefs Terms $ tho' the JanfeniLls and Jefuits are ftill greatly divided abouc the real Doctrine of St.Auguflin, in this Article ; each in- terpreting him confidently with their own Scheme. Sec Jansenist, &c.

Father Sirmond contends for an antient Sect otPredeJli- narians, cotemporary with St. Augufin himfelf, and who had their Rife in Africa, in the Monaftery of Afdrumet j from a Mifunderftanding of St. Auguftine\ Doctrine. 'Tis added, that the Opinion fpread thence throughout the Gauls, where one of them, a Prieft named Lucidus, was condemn'd by Faufais Bifhop of Rhegio $ and his Sentence confirm 'd by two Councils.

The Doctrine was again broach'd in the ninth Century by Godsfcha'.chus a SeneditJine; who, as Hincmar in a Letter to Pope Nicholas, fays, maintained with the antient Predeflinarians who had been already anathematized, that God predeftinated fome to eternal Life, and others to eternal Death ; that God did not will all People to be faved ; that Jefus Chrift did not die for all, but only the Elect or thofe that are faved, ££c. See Grace, &g.

This Doctrine was again condemn'd in a Synod held at Mentz: But the Janfemfts, particularly the Friends of Meff. de Port -Royal, and among the reft, the Prefident Manquin, have refuted F. Sirmond-? and fliewn, that the Ht-refy of the Predefliuarians is a mere Chimera ; adding, that S. Fulgent ius, S. Vrofper, and the other Difciples of S.Augufin, only look'd on it as an imaginary Herefy, in- vented by the Enemies of S. A f/gi' fine's Doctrine, to tra- duce it. In effect, the chief Evidence Father Sirmond produces to the contrary, is the Priefls of Marjl'illes, who 10 K are