Page:Cyclopaedia, Chambers - Volume 2.djvu/474

 POS

POSTIQUE, or Postic, in Architecture, &c. An Or- nament of Sculpture is faid to be 'Poftique, when it is added after the Work itfelf is done.

A Table of Marble, or other Matter, is alfo faid to be IPojlique, when it is incruftated in a Decoration of Archi- tecture, tile.

The Word is form'd from the Italian, 1>opccio, added.

POSTLIMINIUM, Postliminy, among the R imam, the Return of one who had gone to fojourn elfewhere, had been banifh'd, or been taken by the Enemy ; to his own Country, and State. Thus call'd, according to Alt. Gellius, from TgJI and limen, q. d. a Return to the fame Limen, i. e. the fame Bounds or Threfhold.

Some, from Amm. Marcell. will have it thus call'd, becaufePerfons were reftored to the Houfe thro' a Hole in the Wall, fop limen, not by going over the Threfhold, which was elteemed ominous.

^Pofliminiwn was alfo a Law whereby one recovered an Inheritance or other Matter that had been lofl.

POSTULATE, in Mathematics, a clear, evident Pro- pofition ; wherein it is affirm'd or deny'd, that fomething may or may not be done. See Proposition.

A thing immediately deduced from the Confideratior: of one (ingle Definition, if it exprefs fomething to agree, or difagree to another, is call'd an Axiom : If it affirm that fomething may or may not be done, it is call'd a Tofiulate.

Thus, e.gr. from the Genefis of a Circle, 'tis evident that all right Lines drawn from the Centre to the Circum- ference, are equal j fince they only reprefent one and the fame Line, in a different Situation : This Proportion, therefore, is eflcem'd an Axiom. See Axiom.

Kut, fince it is evident from the fame Definition, that a Circle may be defcribed with any Interval, and from any Point ; this is accounted a 'Pop/late.

Axioms, and Vofittttttes, therefore, feem to have nearly the fame relation to each other, that Theorems and Pro- blems have. See Theorem,^-

POSTULATION, in the Canon-Law, the Nomination of a Perfon to a Dignity in the Church ; to which, by the Canons, he cannot be ekaed ; as, for want of Age, of Birth, becaufe already poffefs'd of a Benefice incompatible therewith, or the like Impediment.

Thus the formal Eleflion of fuch a Perfon being faulty, they are obliged to proceed by way of Tofiulation ; that is, the Chapter befeeches the Petfon to whom the Confir- mation of the Election belongs, to approve of it, tho' it be not Canonical.

The Perfon to whom the Supplication is made by the Froteftants in Germany, is the Empetor ; by the Papifls, " the Pope.

t! tcqtiefort obferves, that when a part of the Chapter ekas, and another 'Populates, the Number of Toflulants muft be twice as great as that of the Electors, to bring the Matter to a 'population. .

POSTURE, in Painting, Sculpture,^- the Situation of a Figure, with regard to the Eye ; and of the feveral prin- cipal Members thereof, with regard to one another 5 whereby its Aaion is exprefs'd. See Attitude.

A good part of the Painter's Art confills in adjufling the •PofimXS i in giving the moil agreeable 'Pofiurcs to his Fi- gures; in accommodating them to the Characfers of tile refpeaive Figures, and the part each has in the Aaion ; and in conducting them and purfuing them through-

Toftures are either Natural, or Artificial. The former ate luch as Nature feems to have had a View to in the Mcchanifm of the Body ; or rather fuch as the ordinary Aaions and Occafions of Life lead us to exhibit, while young, and the Joints, Mufcles, Ligaments, kic. flexible

Artificial are thofe which fome extraordinary Views, or Occafions lead us to exhibit : Such, e.gr- are thofe of our 'Poflure-Mtlflen.

A Painter would be ftrangely puzzled with the Figure cfClark, (the late famous •Pofture-Mafter of 'Pall-Mall) in a Hifloty-piece. This Man, as we find in the Fbilof. 'trar.CaS. had fuch an abfolme Command of his Mufcles, i£c. that he could disjoint almoft his whole Body ; fo that he impos'd on that great Surgeon, Mullens; who look'd on him in fuch a tniferable Condition, he would not un- dertake his Cure. Tho' a well-made Man, he would ap- pear with all the Deformities imaginable: Hunch-back'd, Pot-belly'd, Sharp-breafted, S?c- He disjointed his Arms, Shoulders, Legs, and Thighs ; and render'dhimfelf fuch an Object of Pity, that he has frequently extorted Money, in quality of a Cripple, from the fame Company he had the Minute before been in, in quality of a Comrade. He would make his Hips Hand a confiderable way out from his Loins ; and fo high as to invade the place of his Back. Yet his Face was the molt changeable part about him j and fhew'cl more 'Poflures than all the reft of him-

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POT

felfi he could exhibit all the uri;outh odd- Faces of a Quaker's Meeting.

VQT- Jjhes, are properly the AJhes of certain Vegetables ufed in the making of Glafs and Soap. See Ashes.

Such are the A/hes of the Herb Kali t call'd alfo Salt- Wort Glafs- Weed, Wc from its great uf'e in Glafs- making. See Glass.

Pot-Apes are alfo call'd Cineres davellati, and make the Bafis of Salt of Tartar, and moft of the lixivial Salts as our Chymifts of late manage 'em for Cheapnrfs See' Kali, &c.

The Bnglljli and Dutch make a confiderable Commerce of Pot-Apes which they bring from about the Slack Sea ; ufing great Quantities thereof in the Preparation of their Cloths, £f?c% thofe Ames being found excellent to fcour withal. See Fulling.

The N&mcPot-Ajkes'is alfo popularly apply'd to all kinds of Ames bought up and down the Counrry, an d mixed together, for the making of green Glafs : But the beft of Englijh Pot-Apes are thofe made of the fmaller common Highway-Thiltle; tho' all Thirties are good. Fern alfo makes excellent Pot-Apes.

POTABLE, fomething that may be taken, orfwallow'd, by wayof Drink. See Drink.

The Chymifls talk much of Rotable Gold, AnrumPo- tabile. See AuRUMatid Gold.

POTENT, orPoTENCE, in Heraldry, a Term for a kind ofaCrofs in the Fi- gure adjoining. See Cross.

He beareth Sable, a Crofs Potent, Or, by the Name of Aleyn.

This Form reprefents the upper end of a Crutch ; for antiently Crutches were call'd Pote?zts.

POTENTIA, Power, or that whereby a thing is capable either of acting, or being acted on. Sec Power.

Hence, Power is of two kinds, Active, and Pajjive.

AEtive Power, call'd alfo by a barbarous, but iigniiicant School-Term, Operativity, is the Efficacy, or Faculty of any Being, in virtue whereof fomething arifes, or is produ- ced by it. Such is the Power of fpeak'mg, in Man.

Pajjive, or Receptive Power, is a Capacity of receiving fome Ac!:; e.gr. rne Capacity of Knowing a Man.

This is alfo call'd Sub'p&iva Potentia, Subjective Power.

1o exifi in Potentia, is ufed among the School-Wri- ters, to denote that Exiilence which a thing has in a Caufe capable of producing ir, but which has not actually pro- duced it : In which it itands oppofed to Exiitence inatitt* See Possibility and Existence.

POTENTIAL, in the Schools, is ufed to denote, and diilinguifh, a kind of Qualities, which are fuppofed to exift in the Body in Potentia only j by which they are capable, in fome manner, of affecting and impreflingon us me Ideas of fuch Qualities, tho' not actually inherent in themf.rlves.

In this fenfe we fay Potential Hear, Potential Cold. &c Brandy and Pepper, tho' cold to the Touch, are Potentially hot.

Potential Cold is a relative Term, by which we mean that fuch a thing is not actually cold to the Touch, but in its Effects and Operations, if taken inwardly. See Cold.

This Quality is fuppofed to arife from the Size, Shape, $0G, of its component Particles, which give fome check or retardation to the Blood's Motion, whereby it is lefs agi- tated, and upon which the fenfible parts of the Body are not fo briskly {-truck by it j the perception of which dimi- nution or change of Motion in the Organs of Feeling, is call'd Cold.

Hence every thing thatleffens the Blood's Motion, with relation to theSenfation before made, is cold ■-, and every thing which increafesit, may be c-AVd Pote?itial Heat. See Heat.

Potential, in Medicine, &c. Cauteries are either Actual, viz. a Button of red-hot Iron ; or 'Potential, as Lime, and other Caullic Drugs. See Cautery.

Potential, in the Schools, is alfo ufed for fomething that has the Quality of a Genus. See Genus.

Grotius ufes the Phrafe Potential Parts of a State, in oppofition to the Subjective Parts.

By Potential, he means thofe Parts which have the So- vereign Power : By Subjective, thofe fubject thereto ; which are that, with regard to the Sovereign Power, that feveral Species are with regard to the Genus, whereof they are thefubjective Parts.

For in the Schools, a Potential Whole is that which has its Parts under it, as a Genus has its Species : to diftingui/h it from an Actual Whole, which has its Parts in itfelf 3 as a Body compofed of Matter and Form.

Grotius maintains, that tho' the Sovereign Power be one and indivifible, yet it may have feveral Potential Parts -. For, as in the Roman Empire, there have been two Po- tential Heads, the one ruling in the Eaft, the other in the Weft; yet the Imperial Authority all the while iingle and