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PRO

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PUG

pyramids of solid masonry, covered on the faces withhieroglyphics.

The term is also particularly applied to the entrance of theacropolis of Athens, which was erected by Pericles , and wasof unusual magnificence.

PROPYLON, an entrance or vestibule.

PROSCENIUM, (Greek) in the ancient theatre, an emi-nence on which the actors performed their parts. The pro-scenium answered to our stage. It consisted of two partsamong the Greeks; one, particularly so called, where theactors performed ; the other was the logeion appropriated tothe singers and the mimics. Among the Romans, the pro-scenium and pulpitum were the same. In modern theatres,the proscenium is the stage opening; and its entablatureusually bears the royal arms, and ornamental devices.

PROSTYLE, a range of columns in the front of a temple.

PROSTYPA (from irpoamra) images carved in such amanner as to be only half raised above the ground, or plain,on which they are formed. They seem to adhere to it, andhave only one side exposed to view. To prostypa is oppo-sed ectypa.

PROTHYRIS, (Greek) in ancient architecture, a wordsometimes used for a cross-beam, or over-thwart rafter ; as,likewise, for a quoin or corner of a wall ; otherwise calledanco. See Console.

PROTHYRUM, (from Trpo&vpor) a porch at the outerdoor of a house, or portal.

PROTRACTOR, (from the Latin protractus, to draw out)an instrument used in surveying, by which the angles takenin the field with a theodolite, circumferentor, or the like, areplotted, or laid down, on paper.

This protractor consists of a semicircular limb, of brass,silver, horn, or the like, divided into 180°, and subtended bya diameter, in the middle of which is a little notch, or lip,called the centre of the protractor.

For fhe convenience of reckoning both ways, the degreesare numbered from the left hand towards the right, andfrom the right hand towards the left.

But this instrument is made much more commodious bytransferring the divisions on the same circumference to theedge of a ruler, whose side is parallel to the diameter, whichis easily done by laying a ruler on the centre, and the severaldivisions on the semi-circumference, and marking the inter-sections of that ruler on the line : so that a ruler with thesedivisions marked on three of its sides, and numbered bothways, as in the protractor (the fourth, or blank side repre-senting the diameter of the circle) is of the same use as aprotractor, and much better adapted to a case.

On the limb of the protractor are sometimes alsoplaced numbers, denoting the angles at the centres ofregular polygons : thus, against the number 5, denotingthe sides of a pentagon, is found 72, the angle at the centreof a pentagon, &c.

The uses of this instrument are, 1. To lay down anangle of any given quantity , or number of degrees , at anypoint , and with any given line.

Example .—Lay the centre of the protractor on thegiven point, and the diameter of the protractor on thegiven line : make a mark against the given degree (say 50)on the limb of the protractor; through which, from the givenpoint, draw a line, and it will give the angle required.

2. To find the quantity of a given angle. —Lay the centreof the protractor on the point of the angle, and the diameteron one of the lines forming it. The degree of the limb cutby the other line (viz. 50) is the number of degrees of theangle required.

3. To inscribe any given regular polygon (a pentagon for

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example) in a circle .—Lay the centre and diameter g 0circle, and make a dot against the number of de c , tb®the angle at the centre, viz. 72. Through this dot a ^ ce ofcentre of the circle draw a line, cutting the circumte jjer®the circle. To the point of intersection, from the P°! u . th‘ 3the diameter cuts the circumference, draw a right “ g[1 in

the c,, ;\ vi ii

two other right lines drawn from the centre, so

u® el

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from the cent^e^' ^ WMJl lines dnwn t0 the ass '

with this nrnfr an Y number of degrees and

drawn on the , act ° r ’ move ‘he index, so that one of the

may fall U Don ’ ^' 0I ? one of t,le lore-mentioned P .a *^ny o?Zt e u .T mb 7 0f Agrees given ; and pr^ e ,

as therp -n-o „• ? Utl ,P arts on the proper edge ot 0 t j,ecentre to th ,nu . tes ® iven : thus, by drawing a line Lr ^the dian?ef th p”? 1 S ° P Hcked off, an angle is obtained j

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all round m “ 8 ln W ’ and a si ”S ie roW ° f gd

t ® W01 'd signi6es false or imperfect diptere i flIld' was sun"

to distinguish this from the diptere :with a double row.

PSEUDO - PERIPTERAL, (Greelc

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false peripteral \ A

columns at the sides I erJD a PP ked to temples in »-

detached f rom 1 * are engaged in the wall, instead ot b

"’alls of the cella’ he- tfie true peripteral building -. ln g carried forward to the inter’ c

On ol

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niations of the portico.

PTE ROMA* the space between the w® 1 *® - ^

4_1„ _1 ef tllP. Del'lSty 1

of ‘ h ?,

cell 3 '

lied

a temple, and the columns of the P eU

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ambulatio. ,,

PUDDLING, the method of backing »rammed into a compact mass, by means of a e y e jPUG-PILING, the same with dove -

tb

line will be a side of the pentagon, which, beingthe compasses, and set off as often as it will go inference, will give points, which, being connected by *—form the pentagon required. °n a

4. To describe any regular polygon (e. gr. an oc ? a f^ f°'given line. —Subtract the angle at the centre, wine i j 35,tractor gives (say 45°) from 180 ; and the remain ^’ a g 0 n,will be the angle included between two sides ol M?.® e ter 0one-half of which is 67£. Applying then the dia oyel . oH ethe protractor over the given line, with the centi ‘fhe cen‘f’extreme ; make a dot against 67jr, to which, from 0 p th®draw a line : apply the protractor to the other en ^ 0 vline, with the centre over the extreme, and ‘* ier , w0 lin e9another angle of 67-^°. From the point where the tb ethus drawn intersect, as a centre, describe a circ e olie s^ 13interval of the given line. The given line will e j„ th®of the octagon ; and this set off as often as ’*■."? pgjng cClircircumference thus drawn, will give points, which,nected, will form the octagon required. ... t jje f° r "

Protractor, Improved, an instrument much h ^ t |, a tmer, but furnished with a little more appara‘ us > f^ble °°angle may be set off to a minute ; which is imp rathe other.

The chief addition is an index fitted on the centre, JjroPjable on it, so as to play freely and steadily °'' er i„ e g, i®‘Beyond the limb, the index is divided, on both te i b;sixty equal parts of the portions of circles, m ® eaC |,

or

the

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planking, ., up0 n

PUGGING, a coarse kind of mortar lai^ [ oUD d &boarding between joists, in order to P revfrom one apartment to another.