Page:Cyclopaedia, Chambers - Volume 2.djvu/430

 PL A

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PL A

Plain Table ; fo that having laid down the Field from A to B, Lines. Such Problems can only hive two Solutions, in re- thence to C and D i you want room, the Line D E running gard a Right Line can only cut a Circle, or,one Circle cut off the Paper: Draw as much of the Line D E as the Paper another in two Points.

will well 'hold, k. DO. And by means of the Divifions on the Edge of the Frame, draw the Line P Q thro' 0, pa- rallel to the Edge of the Table H M •, and thro' the Point of Interfeftion O, draw ON parallel to MZ. This done, take off the Frame, remove the Sheet, and clap a frelh one (Fig. 36.) m its tead i drawing on it a Line R S near the other Edge parallel thereto. Then lay the firft Sheet on the Table, fo as the Line PQlie exactly on the Line R S, to the belt Advantage, as at O. Laftly, draw as much of the Line O D, on the frefh Sheet, as the Table will hold ; and from O continue the Remainder of the Line D, to E. From E proceed with the Work as before to F, G, and A.

Vfe of the Plain Table, as a Theodolite, Semicircle, or Circumferentor.

The great Inconveniency of the "Plain Table is, that its Paper renders it impracticable in moift Weather. Even the Dew of the Morning and Evening is found to fwell the Pa- per confiderably, and of confequence to ilretch and diftort

the Work To avoid this Inconvenience, and render the

Inftrument ufeful in all Weathers; by leaving off the Paper,

Plain Place, in Geometry, Locus planus, or Locus ad planum, a Term which the ancient Geometricians ufed for a Geometrical Locus, when it was a right Line, or a Circle ; in oppolition to a folid Place, which was an Elliplis, Para- bola, or Hyperbola.

Thele plain Loci the Moderns diftinguifh into Loci ad re- ffam, and Loci ad Circulum. See Locus.

Piai N, in Heraldry, is_ fometimes ufed for the Point of the Shield, when couped 1'quare ; a Part remaining under/ the Square, of a different Colour, or Metal, from the Shield. ,

This has been fometimes ufed as a Mark of Baft.irdy, and call'd Champagne: For when the legitimate Defendants of Baftards have taken away the Barr, Fillet, or Traveife bore by their Fathers, they are to cut the Point of the Shield, with a different Colour call'd Plain. See Bastard, Dimi- nution.

Plain, or Plan e, in Perspective, in Mechanics, A- ftronomy, &c. See Plane.

P L A 1 N T, in Law, is the propounding or exhibiting any Action, real or perfonal, in Writing. See Action.

Hence, the Party making this Plaint, is call'd Plaintiff.

and letting up a Pin in the Centre, it becomes a Theodo- See Plaintiff. lite, a Semicircle, or a Circumferentor, and practicable like PLAINTE, in the ancient Cufioms of France, was a

them. Requeft, or Petition, prefehted to the King, againft the

The Plain Table ftripp'd of its Paper, becomes either a Judges of the Provinces, and afterwards againft Bailiffs and

Theodolite, or a Semicircle, or as that lide of the Frame which has the Projection of the Degrees of a Circle, or a Semicircle, is turn'd upwards. If it be to ferve for a Theodolite ; the In- dex, which as a Plain Table turns on any Point as a Center, is constantly to turn about the Brafs Center Hole in the Middle of the Table.

If for a Semicircle, it mult turn on the other Brafs Center Hole •, in both Cafes 'tis done by means of a Pin rais'd in the Holes.

When the Plain Table is to ferve as a Circumferentor ; fcrew the Compafs to the Index, and both of them to the Head of the Staff, with a Brafs Screw-Pin fitted for the Purpofe ; fo as the Staff and Table (landing fix'd, the Index, Sights, &e. may be turn'd about and vice verfa.

To tak an Angle by the Plain Table, confidered as a Theo- dolite. uppofe the Quantity of the Angle E K G (Fig. 20.)

required. Place the Inftrument at K, the Theodolite Side of the Frame upwards, laying the Index on the Diameter. Turn the whole Inftrument about, the Index remaining on the Diameter, 'till thro' the Sights you fpy E. Screw the Inftrument fad there, and turn the Index on its Center, 'till

Senefchals; for denying Juftice, or for rendering Judgment contrary to the Laws of the Realm.

For in thofe Days there was no Appeal from their Deci- sions ; but they all pronounced at the laft hand : So that the Plainte was not directed againft the Party, but aeainft the Judge-, who wasajourn'd to fee his own Sentence declared null.

This was a kind of Supplement to the Way of Appeals, which was then fhut up.— Thefe Plaintcs, in the Capitula- ries of Charlemaign, are call'd BlafphemU.

PLAINTIFF, in Law, he that fues, or complains, m an Affize, or in an Action perfonal ; as, in an Action of Debt, Trefpafs, Deceit, Detinue, and the like. See Action.

PLA1STER, in Building. See Plaster, Mor- t a s,&c.

Plaister, in Medicine. See Emplaster.

PLAIT. See Fold.

P L A N, a Reprefentation of fomething drawn on a Plane. See P L a n e •, fee alfo Map, Chart, &c.

Such are Maps, Charts, Ichnographies, &c. See P l a- n isp her E.

Plan, in Architecture, &c. is particularly uled for a

thro' the Sights you fpy G.

The Degree here cut on the Frame by the Index, is the Draught of a Building, filch as it appears, or is intended to Ouamity of the Angle fought ; which may be laid down on Pa- appear, on the Ground ; (hewing the Extent, Divifion, and perbytheRijlesof common Protraftion. See Protraction. Diftribution of its Area into Apartments, Rooms, Piffges, Thus may you proceed to do every thing with the Plain &c. See Building.

The Plan is the firft Device or Sketch the Architect makes -, it is alfo call'd the Ground-Plot, Plat-Form, and Jchncgrapky of the Building. See Ichnographv, &c.

The Geometrical Plan is that wherein the folid and vacant Parts are reprefented in their natural Proportion.

Rais'd Plan is that where the Elevation, or Upright, is (hewn upon the Geometrical plan, fo as to hide the Di/hi- bution. See Elevation.

Perfpeltive Plan is that conducted and exhibited by Degra- dations, or Diminutions, according to the Rules of Perlpe- ftive. See Perspective.

To render the Plans intelligible, 'tis ufual to diftinguifh the Ma (lives with a black Waih. The Projeftures on tlie Ground are drawn in full Lines, and thofe fuppofed over them in dotted Lines. The Augmentations or Alterations to be made, are diftinguKhed by a Colour different from what is already built ; ;

Table, as with the common Theodolite. See Theodo-

LITE.

To tale an Angle with a Plain Table, confidered as a Semi- circle. Proceed in the fame manner with the Inftrument

confider'd as a Semicircle, as when confidered as a Theodo- lite ; only laying the Semicircular Side upwards, and turn- ing the Index on the other Center Hole in the middle of the Length, and at about % of the Breadth of the Table. See

Semicircle. .".-■■_.„ r ,,

To take an Angle with the Plain Table, confidered as a

Circumferentor. Suppofe the former Angle E KG required.

Place the Instrument at K, the Flower-de-luce towards you. Direct the Sights to E, and obferve the Degree cut by the South End of the Needle which fuppofe 296. Turn the In- ftrument about, the Flower-de-luce (till towards you, and direct the Sight to G, noting the Degree cut by the other End of the Needle, which fuppofe 182. Subtract the lefs from the greater, the Remainder 114 is the Quantity of the Angle fought. If the Remainder chance to be more than 1S0 then it mufi be again subtracted from 360. This fe- cond Remainder will be the Angle required ; which may be protracted, &c. as under the Article Protract ion.

Thus may you proceed to do every thing with the Plain Table as with the common Circumferentor. See Circum- ferentor. _ T, , , , ,

Plain Number, is a Number that may be produced by the Multiplication of two Numbers into one another. Thus 20 is a

and the Feints of each Plan made the Remain'd'er 114 is the Quantity of lighteras the "Stories are rais'd.

In large Buildings 'tis ufual to have fo many feveral Plans for the firft three Stories.

For the Perfpeltive of a Plan. See Perspective.

PLANCERE, in Architecture, the under Part of the Corona, or Drip; making the fuperior Part of the Cornice, between two Cymatiums. See Corona, Cornice, ci-c.

PLANE, or Plan, Plain, Planum, in Geo- metry, a plain Figure ; or a Surface, lying evenly between its bounding Lines. See Plain.

Wolfius defines it a Surface, from every Point of whofe Perimeter a Right Line may be drawn to every other Point

ilain Number, produced by the Multiplication

of 5 into 4. See Number

Plain Problem, in Mathematicks, is filch an one, as in the lame, cannot be folved Geometrically, but by the Interaction ei- As the right Line is the fhorteft Extent from one Point

ther of a Right Line and a Circle ; or of the Circumferences to another ; fo is a Plane the fhorteft_ Extenfion between

of two Circles. See Problem. one Line and another. See Line and Space.

Such is the Problem following Given, the greateit Side, Planes are frequently uled m Astronomy, C-c. for

and the Sum of the other two Sides, of a Right-angled Tri- imaginary Surfaces, fuppoled to cut, and pals thro' folid Bo- angle ; to find the Triangle. Such alfo is this, To defcribe dies -, and on this Foundation it is that the whole Doctrine

a Trapezium that (hall make a given Area of four given of Conic Sections and of the Sphere turn. See Section. r When