"4S5 
P OR 
P O R 
1 by the same process used in making the 
i pe-lun-tse : the stone is first washed and pul- 
ciised ; it is then thrown into water, and 
Jeter it has been purified it throws up a kind 
01 cream. To 100 pounds of this cream is 
added one pound of che-kao, a mineral some- 
Oiiiig like alum, which is put into the fire 
fill it becomes red-hot, and then pounded. 
1 his mineral is a kind of runnet, and gives a 
consistence to the oil, which is however care- 
fully preserved in its state of fluidity. The 
oil thus prepared is never employed alone ; 
another oil must be mixed with it, which is 
extracted from lime and fern-ashes, to 100 
pounds of which is also added a pound of 
che-kao. When these two oils are mixed, 
Utey must be equally thick ; and in order to 
. ascertain this, the workmen dip into each of 
them some cakes of the pe-tun-tse, and, by in- 
specting their surfaces closely after they are 
orawn out, thence judge of the thickness of 
tne liquors. With regard to the quantity ne- 
cessary to be employed, it is usual to' mix 
teii measures of stone-oil with one measure 
°f the oil. made from lime and fern-ashes. 
In forming vessels of porcelain, the first 
fifing is to purify the pe-tun-tse and kao-lin, 
winch, for the first, is done after the manner 
already described in preparing the squares ; 
far the second it is sufficient to plunge it into 
an urn of water, in an open basket, as it 
"ill easily dissolve. T he dregs that remain 
are perfectly useless, and are emptied out of 
tne work-house when a quantity is got to- 
gether. 5 
To make a just mixture of pe-tun-tse and 
kao-lin, regard must be had to the fineness of 
the porcelain to be made ; for the finer 
porcelain they use equal quantities; four 
parts of kao-lin to six of pe-tun-tse for mode- 
rate ones ; and never less than one of kao-lin 
to thr.ee of pe-tun-tse for the coarsest. The 
hardest, part of the work is the kneading 
and tewing the two earths together, which is 
done till the mass is well mixed, and grows 
hard, by the workmen trampling it continu- 
ally with their feet. Then being taken out 
of the basons or pits wherein it is kneaded, 
it is done over a second time, but piecemeal, 
and with the hands, on large slates for that 
purpose : and on this preparation it is, that 
the perfection of the work depends ; the 
least heterogeneous body remaining in the 
matter, or tlie least vacuity that may be 
jound in it, being enough to spoil the whole. 
I he porcelain is fashioned or formed either 
with the wheel like our earthenware, or in 
moulds. See Stone-ware. 
Smooth pieces, as urns,. cups, dishes, &c. 
a> e made with the wheel ; the rest, such as 
are in relievo, as figures of men, animals, &c. 
are formed in moulds, but finished with the 
chisel. The large pieces are made at two 
operations : one piece is raised with the wheel 
by three or four workmen, who hold till it 
lias acquired its proper figure: which done, 
they apply to it the other half, which has 
been formed in the same manner, uniting the 
two with porcelain-earth made liquid by add- 
ing water to it, and polishing the juncture 
with a kind of iron spatula. After the same 
manner it is that they join the several pieces 
ot porcelain formed in moulds, or by the 
hand ; and that they add handles, &c. to the 
cups, and other works formed by the wheel. 
'The moulds are made after the same man- 
ner wich those of our sculptors, viz. of divers 
pieces which severally give their respective 
figure to the several parts of the model to be 
represented, and which are afterwards united 
to form a mould for an entire figure. The 
earth they are made of is yellow, and fat. 
Is is kneaded like potter’s-earth ; and when 
sufficiently mellow, tine, and moderately dry, 
beating it stoutly, they form it into moulds, 
according to the works required, either by 
hand, or on the wheel. 
All the works that are made in moulds are 
finished by the hands, with several instruments 
proper to dig, smooth, polish, and to touch 
up, the strokes that escape the mould, so that 
it is rather a work of sculpture than of pot- 
tery." I here are some works whereon re- 
lievos are added, ready-made, as dragons, 
flowers, &c. others that have an impression 
in creux, which last are engraved with a kind 
of puncheons. In general, all porcelain-works 
are to lie sheltered from the cold ; their na- 
tural humidity making them liable to break 
when they dry unequally. 
PORCH. SeeA R CHITECTURE. 
PORCUPINE. See Histrix. 
PORE, in anatomy, a little interstice or 
space between the parts of the skin, serving 
for perspiration. See Cutis, Perspira- 
tion, Physiology, See. 
PORELL A, in botany, a genus of mosses, 
the anthera of which is multi locular and fo- 
raminose. 
POROSd EM A, a genus of the polya- 
delphia polyandria class and order. The j 
calyx is six-parted ; no corolla ; filaments i 
nine, with four anthers on eacli ; capsules ; 
covered, six-celled. There is one species, 
a tree of Guiana. 
PORPHYRY, a genus of stones belong- 
ing to the order of saxa. It is found of se- 
veral different colours, as green, deep red, 
purple, black, dark brown, and grey. Under 
the name of porphyry, Mr. Kirwan and M. 
de Saussure include those stones which con- 
tain either feltspar, schoerl, quartz, or mica, 
with, other species of crystallized stone on a 
siliceous or calcareous ground. There are. a 
great many different kinds. M. Ferber de- 
scribes twenty varieties under four species ; 
but in general it is considered with relation 
lo its ground, which is met with of the co- 
lours already mentioned. When the ground 
is of jasper, the porphyry is commonly very 
hard ; the red generally contains feltspar in 
small white dots or specks, and frequently, 
together with these, black spots of schoerl. 
I he green is often magnetic, and is either a 
jasper or schoerl, with spots of quartz. Some- 
times a porphyry of one colour contains a 
fragment of another of a different colour. 
I hose that have chert for their ground are 
fusible per sc. The calcareous porphyry 
consists of quartz, feltspar, and mica, in sepa- 
rate grains, united by a calcareous cement ; 
and, lastly, the micaceous porphyry consists 
of a greenish grey micaceous ground, in 
which red feltspar and greenish soap-rock 
are inserted. 
The porphyry of the antients is a most 
elegant mass of an extremely firm and com- 
pact structure, remarkably heavy, and of a 
fine strong purple, variegated more or less 
with pale red and white its purple is of all 
degrees, from the claret-colour to that of the 
violet ; and its variegations are rarely dis- 
posed in veins, but spots, sometimes very 
3 
P O R 
small, and at others running into large 
blotches. It is less fine than many of the 
ordinary marbles ; but it excels them all in 
hardness, and is capable of a most elegant 
polish. It is still found in immense strata in 
Egypt. 1 he hard red lead coloured por- 
: phyry, variegated with black, white, and 
green, is a most beautiful and valuable sub- 
stance. It has the hardness and ail the other 
characters of the Oriental porphyry ; and even 
greatly excels it in brightness and in thebeauty 
and variegation of its colours. It is found in 
great plenty in the island of Minorca ; and is 
well worth importing, being greatly superior 
to all the Italian marbles. The hard, pale- 
red porphyry, variegated witli black, white, 
and green, is of a pale flesh-colour, often 
approaching to white. It is variegated in 
blotches from half an inch to an inch broad. 
It takes a high polish, and emulates all the 
qualities of the Oriental porphyry, it is found 
in immense strata in Arabia Petrsea, and in 
the Upper Egypt ; and in separate nodules 
in Germany, England, and Ireland. 
Ficoroni takes notice of two exquisitely 
fine columns of black porphyry in a church 
at Rome. In Egypt there are three cele- 
brated obelisks or pillars of porphyry ; one 
near Cairo, and two at Alexandria. The 
French call them aguglias, and in England 
they are called Cleopatra’s needles. 
The art of cutting porphyry, practised by 
the antients, appears now lo be lost. Indeed 
it is difficult to conceive what tools they used 
for fashioning those huge columns and other 
porphyry-works, in some of the antient build- 
ings in Rome. 
Da Costa, however, supposes, that the 
method used by the antients in cutting and 
, engraving porphyry was extremely simple, 
I ai 'd that it was performed without the aid of 
I any scientific means that are now lost. He 
I imagines, that, by unwearied diligence, and 
witli numbers of common tools at great ex^ 
pence, they rudely hewed or broke the stone 
into the intended figures, and by continued 
application reduced them into more regular 
designs; and that they completed the work 
by polishing it with great labour, by the aid 
ot particular hard sands found in Egypt. And 
he thinks, that in the porphyry-quarries there 
were layers of grit or loose disunited par- 
ticles, analogous to the porphyry, which they 
carefully sought for, and used lor this work. 
PORI', a harbour or place of shelter, 
where ships arrive with their freight, and 
customs from goods are taken. 
Port-holes, in a ship, are the holes in 
the side or the vessel, through which are put 
the muzzles of the great guns. These are 
shut up in storms, to prevent the water from 
driving through them. The English, Dutch, 
and I rench ships, have the valves or case- 
ments fastened at the top of the port-holes, 
and the Spanish vessels aside of them. 
Port-royal, the name of two monas- 
teries of cistercian nuns, in the diocese of 
Paris; the one near Chevreuse, at the dis- 
tance of five leagues from Paris, called Port 
royal of the fields, and the other in Paris, in 
the suburbs of St. James’s. 
1 he nuns of the former of these monaste- 
ries, proving refractory, were dispersed; when 
many ecclesiastics, and others, who were of 
the same sentiments as these religious, retir- 
ed to Port Royal, took apartments there. 
