Page:Cyclopaedia, Chambers - Volume 2.djvu/475

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indivifible : So is it poffible the Subjective Parts com- bining to give away their Sovereignty, may not give it m- tire, but refervea part of it for certain Emergencies. In which Cafe the Subjective part becomes Potential. And thus there are two Potential parts, yet the Sovereignty

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Potential, in Grammar, gives the Denomination to one of the Moods. See Mood.

The Potential Mood is the fame in Form, with the Sub- junctive ; but differs from it in this, that it hath always implied in it, either foffum, volo, oxdebeo; asRoget, that is Rogare fotejl, a Man may ask. See Subjunctive. .

It is fometimes called the permiffive Mood, becaufe it often implies a Permifiion, or Conceffion to do a thing ; as, Hal/eat, iialeat, vivat, ctim ilia Terent.

POTION, a liquid Medicine, in form of a Draught, to be taken at one time.

There are purging Potions, Emetic Potions, Diaphoretic, Pefloral, Cephalic, Cardiac, Stomachic, Hyfteric, Vul- nerary, Carminative, ££c. Potions.

POTTERY, the Art of making Earthen-Pots, and Veffels ; or, the Manufactory of Earthen-Ware. See

ThcJVheeUnA Zathe are the Chief, almoft the only In- ftruments, ufed in Pottery ; the firft for large Works, the fecond for fmall : The, in reality, they are much the fame as to the manner of uiing them.

The Potter's Wheel confitls principally in its Nut, which is a Beam or Axis, whofe Foot or Pivot plays perpendicu- larly on a Free-ftonc Sole or Bottom. From the four Corners a-top of this Beam, which does not exceed two foot in height, arife four Iron Bars, call'd the Spokes of the Wheel; which forming diagonal Lines with the Beam, defcend, and are faften'd at bottom to the Edges of a ftrong wooden Circle, four foot in Diameter, perfectly like the Felloes of a Coach-Wheel, except that it has neither Axis nor Radii ; and is only join'd to the Beam, which ferves it as an Axis, by the Iron Bars. The Top of the Nut is flat, of a circular Figure, and a foot in diameter. On this is laid a piece of glaz'd Earth, to be turn'd and falbion'd.

The Wheel thus difpofed, is encompaiied with four Sides of four different pieces of Wood, fuftain'd on a wooden Frame : The hind-piece, which is that whereon the Workman fits, is made a little inclining towards the Wheel : On the fore-piece are placed the pieces of pre- pared Earth. Laflly, the fide-pieces ferve the Workman to reft his Feet againft ; and are made inclining to giye him more orlefs room, according to the Size of the Veflel to be turn'd. By his fide is a Trough of Water, where- with from time to time he wets his Hands, to prevent the Earth's flicking to 'em.

To life the Wheel. The Potter having prepared his Earth, and laid a piece of it fuitable to the Work he intends, on the Top of the Beam ; fits down ; his Thighs and Legs much expanded, and his Feet relied on the fide-pieces, as is moil convenient.

In this Situation he turns the Wheel round, till it has got the proper Velocity i when, wetting his Hands in the Water, he bores the Cavity of the Veflel, continuing to widen it from the middle ; and thus turns it into Form : turning the Wheel a-frelh, and wetting his Hands, from time to time. ,.

When the Veffel is too thick, they ufe a flat piece of Iron with a Hole in the middle, and fomewhat /harp on one Edge, to pare off what is redundant. Laflly, when the Veffel is fini/h'd, they take it off from the circular Head by a Wire pafs'd underneath the Veffel.

The 'Potter's Lathe, is alfo a kind of Wheel, but fimpler and (lighter than the former. Its threechief Members are an Iron-Beam or Axis, three foot and an half high, and two Inches in Diameter ; a little wooden Wheel all of a piece, an Inch thick, and feven or eight in Diameter, pla- ced horizontally atop of the Beam, and ferving to form the Veflel on ; and another larger wooden Wheel, all of a piece, three Inches thick, and two or three Foot broad, faften'd to the fame Beam at bottom, parallel to the Ho- rizon. The Beam or Axis turns by a Pivot at bottom, in an Iron Stand.

The Workman gives the Motion to the Lathe with his Feet," by pufhing'the great Wheel alternately with each Foot'; flill giving it a greater or lefs degree of Motion, as his Work requires.

They work with the Lathe, with the fame Inftruments, and after the fame manner, as the Wheel.

But neither the one nor the other ferve for any more than the forming of the Body of the Veffel, ($c. The Feet, Handles, and Ornaments, if there be any, befide the Mouldings, being to be made andfet on by Hand ; If there be any Sculpture in the Work, 'tis ufually done in Earthen or Wooden Moulds, prepared by a Sculptor, un-

lefs the Potter have Skill enough to do it himfelf, which i very rare.

As to the Glazing, or Varnifhing of the Work ; tis ufually done with mineral Lead, i. e. Lead pulveriz'd by throwing Charcoal-Duff into the melted Lead, and the Alhes of Lead ; which, in effect, are only its Scum and Scoria. See Lead.

For the Chinefe Pottery, fee Porcelain.

POTTLE, an Englijh Meafure, containing two Quarts. See Measure.

Two of thefe Pottles, in the Liquids, make a Gallon • but in dry Meafure rhree go to a Gallon. See Gallon.

POUDER, or Powder, in Pharmacy, a dry Medicine pulveriz'd, or prepared by being broken and reduced into almoft imperceptible Atoms, either in a Mortar, or by Chymical Operations, ££c. See Pulverization.

Fouder of Viper, Viperine Pouder, has of late days come much in requefl. See Viperine.

Styptic Pouder, Sympathetic Ponder, Sic. SeeSTYPnc, Sympathetic, &c.

Pouder for the Hair, is Flower of Wheat, or Beans, well lifted and prepared, to give it an agreeable Odour.

That wherein Starch Grounds is mixed, is the word. See Starch.

Jefuits Pouder, Pulvis Patrum. See Cortex Pertt- vianus.

G//«-Pouder, fee Gvw-Powdcr.

Pouder Chefs, in the Sea-Language, are Boards join'd in form of a Triangle, and fill'd with Gun-powder, Pebbles, &c. which they fet fire to when the Ship is boarded by an Enemy, and foon make all clear before 'em.

POUDERINGS, in Building, a Term fometimes ufed for Devices ferving to fill up vacant Spaces, in carv'd Works : As alfo, in Efcutcheons, Writings, l£c.

Pouderings, in Heraldry, fee Fur.

POULTICE, orPouLTis, a Form of Medicine call'd alfo Cataflafm. See Cataplasm.

POULTRY, fee Fowl.

POUNCE, among Artificers, a little Heap of Charcoal- Dull, inclofed in fome open Stuff"; to be pals'd over Holes prick'd in a Work, in order to mark the Lines or Defigns thereof on a Paper placed underneath; to be afterwards finifh'dwith a Pencil, a Needle, or the like.

'Pounce is much ufed by Embroiderers, to transfer their Patterns upon their Stuffs ; by Lace-Makers, and fome- times alfo by Engravers, and Writing- Mailers.

The Word is form'd trom the French, Pounce, Pumice- flone ; in regard they antiently ufed Pumice-Hone powder'd for this purpofc.

Pounces, in Falconry, the Talons, or Claws of a Bird of Prey.

POUND, a Weight, of a certain Proportion, much ufed as a Standard for determining the Gravities and Quantities of Bodies. See Weight.

The Word is derived from the Saxon, Pund, Pondus, Weight.

We have two different Pounds in England; the Pound Troy, and the Pound Auerdupis.

The Pound Troy confifts of i: Ounces, each Ounce* of 20 Penny-weights, and each Penny-weight of 24 Grains ; fo that 4S0 Grains make an Ounce, and 57^0 Grains a Pound. See Ounce, &c.

ThisPound isuled in the weighing of Silver, Gold, pre- cious Stones, all kinds of Grains, ££c

It is alfo ufed by the Apothecaries, tho' differently di- vided : Among them 2+ Grains make a Scruple, 5 Scruples a Drachm, 8 Drachms an Ounce, and 12 Ounces a Pound. See Scruple, &c.

The Pound Avoirdupois confifts of 10" Ounces; but then the Avoirdupois Ounce is lefs by 42 Grains than the Troy Ounce, which amounts to nearly a 12th part of the whole; fo that the Ounce Avoirdupois only contains 438 Grains, and the Troy Ounce 480.

The difference whereof is nearly as that of 73 to So ; l. e. 73 Ounces Troy make 80 Ounces Avoirdupois. 112 Avoirdupois Pounds make the Hundred Weight, or Quintal. See Quintal.

By this Pound are weigh'd all large and coarfe Com- modities, Flefh, Butter, Cheefe, Iron, Hemp, Lead, Sreel, £?c.

An Avoirdupois Pound is equal to 14 Ounces i of a Paris Pound. So that 100 of the formzrPcllnds make pi of the latter.

The French Pound contains 16 Ounces ; but one French Pound is equal to one Pound one O^nce | of an Avoirdupois Pound ; fo that ico Paris Foitnds make 109 Englijh Avoir- dupois Pounds.

The Paris Pound is divided in two manners; the firft divifion is into two Marcs, the Marc into eight Ounces, the Ounce into eight Grofs, the Grofs into three Deniers, the Denier into twenty lour Grains, each weighing a Grain of Wheat.

The