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PERIRRANTERION, (from the Greek wept, about, andpaivw, to sprinkle,') lustral vases placed at the entrances ofheathen temples, in which the priests washed their hands,' andwith which they sprinkled their worshippers.

PERISTYLE , (from the Greek* wtptwvXog, formed fromwept, about, and wvXog, column,) in ancient architecture, aplace or building, encompassed with a row' of columns qn theinside ; by which it is distinguished from the periptere, wherethe columns are disposed on the outside. Such was thehypsethral temple of Vitruvius , and such are now somebasilicas in Rome, several places in Italy , and most cloistersof religious houses.

Peristtle is also used by modern writers for a range ofcolumns, either within or without a building : thus we say,the Corinthian peristyle of the portal of the Louvre, &c.

PERISTYLION, (from the Greek wept’svXiov,) among theAthenians , a large square place, though - sometimes oblong,in the middle of the gymnasium, designed* for walking, andthe performance of those exercises which were ■ not peculiarto the palsestra.

PERISTYLIUM , a continued row or series of rows ofcolumns all round a court or building, in contradistinction toporticos, in which the pillars do not surround a space, but arearranged in one- or more parallel lines.

PERITHERIDES, the same as Ancones.

PERITROCHUJM, (from wept, about, and rpoKtXog, a'cir-cle,) in mechanics, a wheel, or circle, concentric with thebase of a cylinder, and moveable together with it, about anaxis. The axis; with the-wheel and levers fixed in it, tomove it, constitutes that mechanical power called axis inperitrochio.

PERPENDICULAR, (from the Latin p&rpendicularis,')in geometry, a line falling -directly'on another line, so as tomake equal angles-on each side; called also a normal line.

From the very notion of a perpendicular, it follows:—

1. That the perpendicularity is mutual; ire., if a line, asis, be perpendicular to another, kh; that other is-alsoperpendicular to the first.

2. That only one perpendicular can be* drawn from onepoint in the same plane.

3. That if a perpendicular be continued through the lineto which it was drawn perpendicular, the continuation willalso be perpendicular to it.

4. That if there be two points of a right line, eaeh ofwhich is at an equal perpendicular distance from two pointsof another right line; the two lines are parallel to eachother.

5. That two right* lines perpendicular to one and the sameline, are parallel to each other.

6. That a line, which is perpendicular to another, is alsoperpendicular to all the parallels of the other.

7. That perpendiculars to one* of two parallel lines, ter-minated by those lines, are equal to each other.

8. That a perpendicular line is the - shortest of all thosewhich can be drawn from the same point to the same rightline.

Hence the distance of a point from a line, is a right linedrawn from the point perpendicular to the line or plane-; andhence the altitude of a figure is a perpendicular let fall fromthe vertex to the base.

Perpendiculars are best described in practice by means ofa square; one of whose legs is applied along -that line; to orfrom which the perpendicular is to be let fall or raised. -

A line is said to be perpendicular to a plane, when it isperpendicular to all right lines, that can be drawn in thatplane, from the point on which-it insists.-

A plane is said to be perpendicular, to another plane, when

all right lines drawn in the one, perpendicular to the csection, are perpendicular to the other. line 3 ’

If a right line be perpendicular to two other r *o piintersecting each other at the common section, it W1pendicular to the plane passing by those two lines. 0 -right lines perpendicular to the same p

ef'

Two

parallel to each other.

If, of- two parallel right lines, the one is perpend^ guC iiany plane, the other must also be perpendicularplane. _ pas«'

If a right line be perpendicular to a plane, any P 1 "ing by that line will be perpendicular to the same p a r pefl'Planes, to which one and- the same right line ia P per*dicular, are parallel to each other : hence all right 1 ,j uUpendicular to one of two parallel planes, are also perp eto the other. u i a r l °

If two planes, cutting each other, be both perpen 1 ,j c ula ra third plane, their common section will also be P er Pto the same plane. ,,; n a- t| ,e

Perpendicular to a Curve, is a right line <» 3 it,curve in the point in which any other right lineand is also itself perpendicular to that tangent. throwsPERPENT-STONE, a long stone reaching -ng wa wall; a bond or thorough-stone. -

PERPEYN-WALL , a projecting pier, buttress, osupport employed to sustain a beam or other we’gu^ ^ r0 a

PERRAULT, CLAUDE, an eminent arci

hitect ’Yessi<””

Paris in 1613. He was brought up to the medical P r .^ jgP-and took his degree as doctor of the faculty of U' 11 * 13 ^

He practised little, however, excepting among n 1 - 0 gand the poor;-and having a decided taste for n r ®'^ flr cli>the fine arts, he turned his-attention to the sciencetecture, in which he became greatly distinguish 6 ' tr on a »''the Academy of Sciences was founded, under the P 0 f v 1 ,of Colbert, in the year 1666, Perrault, who was ob^gfirst members; was appointed to select a spot f° r . vV asvatory ; and he also gave a plan of the building w *

be executed. When it-was resolved, under Do t >

to proceed in completing the palace of the L° 0 f t‘ - in <1 es !°.„ 0 oU° te

eminent architects were invited to give

fagade; and that of Perrault was preferred. Tins i jj al° athe masterpiece of French architecture, and it It-" jsuffice to transmit his name with honour to P° ster 'jj e a''° ur ! ;in vain that persons, jealous of his reputation, e j, e V ea j tto make the public believe that the real designer w« j> e rr» athey entirely failed in their proof, and the gl 0I T Ring’s 1

remained untarnished. When Colbert, p.fter at c

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conquests; proposed to constructTgrand triumphhis honour, Perrault’s design had the preference,edifice was commenced. It was, however.

In its masonry, Perrault employed the practice oi jt »-of rubbing the surface of the stones together with &water, so as to make them cohere without wor® 1 - fworks of this architect were, the chapel at Sc ? a

water-alleyat Ver Cb „ rck of Petits Peres —

in the park offh!! e 'V n<1 m °st of the designs of‘h«

undertook a transW* pa a £ e ‘ % the king's comm* . glte din 1673. All a " at,on of Vitruvius , with notes, P u :\ Y e( e<Wn by bi"™ i'fs for the plates of this work.

of the kind H*’ 3n / lave been esteemed as mas <ilthat author fnrTh aherwar * published an abrnthe-study of nmh-f USe stu, lents. He likewise

Ci ”9Eiices 2 cT W(> by a work entitled 0rd ?M*

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