PUN

346

P U Z

Iii the former cases, the force of the power is augmented inan arithmetical proportion of the number of ropes or pulleys;but in this, in a geometrical proportion.

3. If a power move a weight by means of several pulleys,the space passed over by the power will be to the space passedover by the weight, as the weight to the power.

Hence, the smaller the force that sustains a weight bymeans of pulleys is, the slower is the weight raised ; so thatwhat is saved in force, is spent in time.

Pulley Mortise, a longitudinal mortise of considerablelength, parallel and near to the under side of the bondingjoists, in order to insert the ceiling joists.

PULPIT, an elevated stage or desk, from which orationsare pronounced, applied more especially to those employedin churches. They are for the most part of wood, but some-times of stone, of which an early and beautiful example existsat Beaulieu, Hants . The greater number of examples areof Perpendicular work, and these principally of wood, andpolygonal in plan ; sometimes with a canopy above. Pulpitsare sometimes found outside of buildings, as at MagdalenCollege, Oxford, and in many instances abroad, where alsoare pulpits of great size and magnificence, capable of con-taining more than one person.

PULPITUM, (Latin ) among the Romans, a part of thetheatre, called also proscenium, or what we now call thestage, on which the actors trod. Though some say it wasproperly an eminence on the stage for the music ; or a sug-gestum, whence declamations, &c.,were spoken.

The French use the word pulpit , pupitre, for a reading-desk in a church, library, or the like : those large ones inchurches they properly called lutrins.

PULVINARlA, (Latin, ) cushions upon which the statuesof the gods were laid in the temples, at the time when thankswere given for some signal victory.

PULVINATED, (from the Latin , pulvinatus ,) in ancientarchitecture, a term applied to a frieze, which swells, orbulges out, in manner of a pillow, pulvinus: whence thename.

PUNCHION, or Puncheon, (from the French , poingon,)a little block or piece of steel, on one end of which is somefigure, letter, or mark, engraven either in creux, or in relievo;impressions of which are taken in metal, or some other mat-ter, by striking it with a hammer. There are various kindsof these puncheons used in the mechanical arts. Such,for instance, are those of the goldsmiths, cutlers, pew-terers, &c.

Punchion, is also a common name for all the iron instru-ments used by the stone-cutters, sculptors, locksmiths, &c., forthe cutting, inciding, or piercing their several matters.

Those of sculptors and statuaries serve for the repairing ofstatues, when they are taken out of moulds.

The locksmiths use the greatest variety of punchions; somefor piercing hot, others for piercing cold; some flat, somesquare, some round, others oval; each to pierce holes of itsrespective figure in several parts of locks.

Punchion, or Punciiin, in carpentry, a piece of timberplaced upright between two posts, whose bearing is toogreat, serving, together with them, to sustain some heavyweight.

The punchion is usually lower and slighter than eitherprick-posts or principal posts, and is joined by a brace, orthe like, of iron. See Post. Those on each side of a door arecalled door-punchions .

Punchion, is also a piece of timber raised upright underthe ridge of a building, in which the little forces, &c., arejointed. Vitruvius calls the punchion columen.

Punchion, is also used for the arbor or principal part

that

ing stage; used by shipwrights for breaming,repairing a ship’s bottom. It is also used in some

head and stern, whose floor resembles the platform " or

caulKiM?

PURBECK STONE, (the saxum arenariuw■ a lbid°Purbecense of Da Costa, and psadurium friabi roU gb>fuscum of Hill,) an alkaline sand-stone, harsh an te lyof a disagreeable ash-colour, very heavy, and mo 1 noroa 3 ’hard ; of a texture not very compact, but somewha P a nand composed Of an angular grit, cemented togeth ^thearthy spar: it cuts freely, and with a tolerably even oi {0 »surface. It will not strike fire with steel, and ^ ul . g j a ndwhite colour. The quarries of this stone are in the 1 j flI1 inPurbeck, in Dorsetshire , whence it is brought to ^ pa ve-great quantities, and there used in buildin S’. an io a')0‘ h fments. Its specific gravity is 2.68. I here is a |?n. v C° 9

kind of Purbeck stone, the saxum fusco-albidum ot P sc xiltt otand the sympexium durissimum splendidum a/6i«07 vn isl'

Hill, which is alkaline, of a dull disagreeable P a e "j t j 3 of 9white colour, and cuts to a very smooth surface ■ j ]tn es 9 >fine, close, compact texture, not quite destitute ot Oj ^jtUbut full of sparks of pure spar, and intimatelyvast quantities of small pectunculi, which are ofte j j ia r(hand filled with the same substance; is very heavy fir®and water does not pervade its texture; it does not col° ur '

with steel, and when burnt acquires a clear as fbuil'HtThis stone is brought from Purbeck, and used f oU nci 1,1pavements, &c. Hill informs us, that it is likewi^ ^, e Jai'g®many other parts of the kingdom, and that theistrata of it in Yorkshire . m bro>d _

PURFLED, (from the French , pourfiler, to r ept eornamental work, whether in stone or other matei^senting drapery, embroidery, or lace-work.

PURLINS, pieces of timber lying across 0 f

the inside, to keep them from sinking in the mi

len S th ‘ . , T he s tr ° n fof

Purlins are supported by the principals. practi ce

method is to make bridges over, as in the presethe construction of roofs. \ a ®ong a

PUTEAL, (from the Latin , puteolus, a we ^h e * eRomans, a small kind of edifice raised in the p ‘

the raft f t beir

abo]

.ufc

thunder-bolt had fallen.

PUTLOGS, or Putlocks, short pieces

seven feet long, used in building scaffolds. ,

angles to the wall, with one of their ends bearing O’ jfcland the other upon the ledges or poles which stand p

t0 orT™l° f the wal1 of the building. „ oste , cor"'

^ Vom the French , potee,) a kind of P as * 9 t>ipounded of whiting, with or without a little white- < (oll g!i

linseed oil, beaten together to the consistence o . gsS ifldough; used by glaziers for fastening the squares ot S jce ssash-windows, &c., and by painters, to stop up ‘ ae t (to#and clefts in timber and wainscot, to prevent tngetting in and ruining the work.

PUZZOLANA, or Pozzolana, a

_.-/-ssS

of volcanic ashes, more or less compacted e P ute ;,,cted>

ri<

from

ej® 6

U 9

ate near mount P n ^ uis Putedlanus,an d in the viein , from which these ashes mo-.,

colours, white re/ 0l h 7 h T h H abou " da - Jt ° £/<

grayish-black. tW Vx? ek ' reddish ’ or reddish-brown-grfa• • ■ ' U)at of Naples is generally gray; that of °‘, rhe

”• 1 — ,-etldish-hrowa

pe> te

Vecchia is more generally reddish, or re < ^ gn j th e ^jcl 1red variety is the proper puzzolana; the a ,^,j je a sh® 9 nt®sorts are called, in Italy , lapillo, or ra P" °' nse bedoverwhelmed Pompeii now form an imm

of 9

of a machine, on which it turns vertically; ascrane, &c. , , s qu ar0

PUNT, a sort of oblong flat-bottomed boat, with „ oA t-

of tinlbe a t rig!fThey h e , inon it,