Tribe 2. _Myopsida_.--No aperture in the cornea. Left oviduct only
developed in female. Internal shell without a distinct phragmacone,
calcified or simply chitinous.
Fam. 1. _Sepiidae_. Body wide and flat; fins narrow, extending the
whole length of the body; shell calcareous and laminated.
_Belosepia_, a rudiment of rostrum and phragmacone present in shell,
Eocene. _Sepia_, shell with a rostrum, British. _Sepiella_, shell
without a rostrum.
Fam. 2. _Sepiolidae_. Body short, rounded at the aboral end; fins
rounded, inserted in middle of body-length; shell chitinous, small
or absent. _Sepiola_, head united to mantle dorsally, British.
_Rossia_, head not united to mantle, British. _Stoloteuthis_ and
_Inioteuthis_, without shell. _Heteroteuthis. Euprymna._
Fam. 3. _Idiosepiidae_. Body elongated, with rudimentary terminal
fins; internal shell almost lost. _Idiosepius_, 1.5 cm. long, Indian
Ocean.
Fam. 4. _Sepiadariidae_. Body short; mantle united to head dorsally;
no shell. _Sepiadarium_, Pacific Ocean. _Sepioloidea_, Australian.
Fam. 5. _Loliginidae_. Body elongated and conical; fins extending
forward beyond the middle of body-length; shell chitinous, well
developed. _Loligo_, fins triangular, aboral, British.
_Sepioteuthis_, fins rounded, extending along whole of body-length.
_Loliolus. Loliguncula._ The following fossil genera, known only by
their gladius and ink-sac, have been placed near
_Loligo_:--_Teuthopsis, Beloteuthis_ and _Geoteuthis_, Lias;
_Phylloteuthis_, Cretaceous; _Plesioteuthis_, Jurassic and
Cretaceous.
SUBORDER 2. OCTOPODA.--Only four pairs of arms, all similar and longer
than the body. Body short and rounded aborally. Suckers sessile. Heart
not contained in coelom. No nidamentary glands.
[Illustration: FIG. 39.--_Palaeoctopus Newboldi_, the oldest Octopod
known. From the Cretaceous rocks of Lebanon. (After H. Woodward.)]
Tribe I. _Leioglossa_.--No radula. Arms united by a complete membrane.
Fins on sides of body.
Fam. _Cirrhoteuthidae_. Tentacular filaments on either side of the
suckers. _Cirrhoteuthis_, pallial sac prominent, fins large,
pelagic. _Opisthoteuthis_, body flattened, with small fins,
deep-sea. _Vampyroteuthis_, four fins. _Palaeoctopus_, fossil,
Cretaceous.
Tribe 2. _Trachyglossa._--Radula present. No fins.
Fam. 1. _Amphitretidae_. Arms united by membrane; funnel attached to
mantle, dividing the pallial aperture into two. _Amphitretus_,
pelagic.
Fam. 2. _Alloposidae_. All arms united by membrane; mantle joined
to head by dorsal band and two lateral commissures. _Alloposus_,
pelagic.
Fam. 3. _Octopodidae_. Arms long and equal, without membrane;
hectocotylus not autotomous. No cephalic aquiferous pores.
_Octopus_, two rows of suckers on each arm, British. _Eledone_,
single row of suckers on each arm. _Scaeurgus. Pinnoctopus.
Cistopus. Japetella._
Fam. 4. _Philonexidae_. Hectocotylus autotomous; arms unequal in
size; aquiferous pores on head and funnel. _Tremoctopus_, two dorsal
pairs of arms united by membrane. _Ocythoë_, without interbrachial
membrane.
Fam. 5. _Argonautidae_. Hectocotylus autotomous; no interbrachial
membrane; extremities of dorsal arms in female expanded and
secreting a shell; males very small, without shell. _Argonauta_.
LITERATURE.--Use has been freely made above of the article by E. Ray
Lankester, on _Mollusca_, in the 9th edition of this Encyclopedia. For
the chief modern works, see Bashford Dean, "Notes on Living Nautilus,"
_Amer. Nat._ xxxv., 1901; Arthur Willey, "Contribution to the Natural
History of the Pearly Nautilus," A. Willey's _Zoological Results_, pt.
vi. (1902); Foord, _Cat. Fossil Cephalopoda in British Museum_;
Alpheus Hyatt, "Fossil Cephalopods of the Museum of Comp. Zoology,"
_Bull. Mus. Comp. Zool._ (Cambridge, U.S., 1868); Jalta, "I Cefalopodi
viventi nel golfo di Napoli," _Fauna und Flora des Golfes von Neapel_,
xxiii. (1896); Joubin, "Céphalopodes de l'atlantique nord," "Céph. de
la Princesse Alice," _Camp. sci. Albert I^er de Monaco_, ix. (1895),
xxii. (1900); Paul Pelseneer, "Mollusca," in the _Treatise on
Zoology_, edited by E. Ray Lankester. (J. T. C.)
CEPHEUS, in Greek mythology, the father of Andromeda (q.v.); in
astronomy, a constellation of the northern hemisphere, mentioned by
Eudoxus (4th century B.C.) and Aratus (3rd century B.C.). Ptolemy
catalogued 13 stars in this constellation, Tycho n, and Hevelius 51. The
most interesting star in it is [delta] _Cephei_, a remarkable double
star, the brighter component of which is a short period variable (5.37
days), with a range in magnitude of 3.7 to 4.9; it is also a
spectroscopic binary.
CEPHISODOTUS, the name of the father and of the son of Praxiteles, both
sculptors like himself. The former must have flourished about 400 B.C. A
noted work of his was Peace bearing the infant Wealth, of which a copy
exists at Munich. Peace is a Madonna-like figure of a somewhat
conservative type; the child Wealth is less successful. Cephisodotus
also made, like his son, a figure of Hermes carrying the child Dionysus,
unless indeed ancient critics have made two works of one. He made
certain statues for the city of Megalopolis, founded in 370 B.C. Of the
work of the younger Cephisodotus, his grandson, we have no remains; he
was a prolific sculptor of the latter part of the 4th century B.C.,
especially noted for portraits, of Menander, of the orator Lycurgus, and
others (see J. Overbeck, _Antike Schriftquellen_, p. 255).
CERAM (_Sirang_), an island of the Dutch East Indies, in the Molucca
group, lying about 3° S., and between 127° 45' and 131° E. Its length is
a little over 200 m., its greatest breadth about 50 m., and its area,
including neighbouring islets, 6621 sq. m. It consists of two parts,
Great Ceram and Little Ceram or Huvamohel, united by the isthmus of
Taruno; and, for administrative purposes, is assigned to the residency
of Amboyna, being divided into Kairatu or West Ceram, Wahai and Amahai,
the northern and the southern parts of Middle Ceram, and Waru or Eastern
Ceram. No central chain of mountains stretches west and east through the
island, but near the north coast hills, rising 2300 to 2600 ft., slope
steeply to the shore. Near the south coast, west of the Bay of
Elpaputeh, a complex mass of mountains forms a colossal pyramid, with
peaks rising to nearly 5000 ft. The isthmus connecting the two parts of
the island is very narrow, and has a height of only 460 to 490 ft. The
chief rivers flow north and south into bays, but are navigable only for
a few miles during the rainy season. The rainfall is very heavy,
amounting to 121 in. (mean annual) on the south coast. On the north
coast the bays of Savai and Waru are accessible for small vessels. The
geological structure, consisting chiefly of eruptive rocks and
crystalline limestone, is similar to that of northern Amboyna. In the
eastern section the prevailing rock is crystalline chalk, similar to
that of Buru. Several hot springs occur, and earthquakes are not
infrequent. About 4000 persons perished in the earthquake of 1899. A
large part of the interior is covered with dense forests, and except
along the coast the population is scanty. For the naturalist Ceram is
without much interest, lacking characteristic species or abundance of
specimens. The Bandanese pay occasional visits to shoot bears and deer;
there are numbers of wild goats and cattle; and among birds are
mentioned cassowaries, cockatoos, birds of paradise, and the swallows
that furnish edible nests. A large number of fish are to be found in the
various rivers; and as early as 1860 no fewer than 213 species were
described. The most valuable timber tree is the iron-wood. Rice, maize,
cocoa-nuts, sugar-cane and a variety of fruits are grown; and some
tobacco is exported to Europe; but by far the most important production
is the sago palm, which grows abundantly in the swampy districts,
especially of Eastern Ceram, and furnishes a vast supply of food, not
only to Ceram itself, but to other islands to the east. The Dutch have
established cocoa and coffee plantations at various points. The
coast-villages are inhabited by a mixed Malay population, Buginese,
Macassars, Balinese and other races of the archipelago. The interior is
occupied by the aborigines, a people of Papuan stock. They are savages
and head-hunters. The introduction of Christianity was hampered by the
baneful influence of a secret society called the Kakian Union, to which
pagans, Mahommedans and Christians indiscriminately attached themselves;
and it has several times cost the Dutch authorities considerable efforts
to frustrate their machinations (see _Tijdschrift van Ned. Ind._, fifth
year). The total population is estimated at 100,000, including 12,000
Christians and 16,000 Mahommedans. The chief settlements are Savai at
the north and Elpaputeh at the south end of the isthmus of Taruno. There
was a Dutch fort at Kambello, on the west side of Little Ceram, as early
as 1646.
CERAMICS, or KERAMICS ([Greek: keramos], earthenware), a general term
for the study of the art of pottery. It is adopted for this purpose both
in French (_céramique_) and in German (_Keramik_), and thus has its
convenience in English as representing an international form of
description for a study which owes much to the art experts of all
nations, though "ceramic" and "ceramics" do not appear in English as
technical terms till the middle of the 19th century.
The word "pottery" (Fr. _poterie_) in its widest sense includes all
objects fashioned from clay and then hardened by fire, though there is a
growing tendency to restrict the word to the commoner articles of this
great class and to apply the word "porcelain" to all the finer
varieties. This tendency is to be deprecated, as it is founded on a
misconception; the word "porcelain" should only be applied to certain
well-marked varieties of pottery. The very existence of pottery is
dependent on two important natural properties of that great and
widespread group of rocky or earthy substances known as clays, viz. the
property of plasticity (the power of being readily kneaded or moulded
while moist), and the property of being converted when fired into one of
the most indestructible of ordinary things.
The clays form such an important group of mineral substances that the
reader must refer to the article CLAY for an account of their
occurrence, composition and properties. In this article we shall only
deal with the various clays as they have affected the problems of the
potter throughout the ages. The clays found on or close to the earth's
surface are so varied in composition and properties that we may see in
them one of the vital factors that has determined the nature of the
pottery of different countries and different peoples. They vary in
plasticity, and in the hardness, colour and texture of the fired
product, through an astonishingly wide range. To-day the fine, plastic,
white-burning clays of the south of England are carried all over Europe
and America for the fabrication of modern wares, but that is a state of
affairs which has only been attained in recent times. Even down to the
18th century, the potters of every country could only use on an
extensive scale the clays of their own immediate district, and the
influence of this controlling factor on the pottery of bygone centuries
has never yet received the attention it deserves.[1]
_General Evolution of Pottery._--The primitive races of mankind, whether
of remote ages or of to-day, took perforce such clay as they found on
the surface of the ground, or by some river-bed, and with the
rudimentary preparation of spreading it out on a stone slab if necessary
and picking out any rocky fragments of appreciable size, then beating it
with the hands, with stones or boards, or treading it with the feet to
render it fairly uniform in consistency, proceeded to fashion it into
such shapes as need or fancy dictated. Fired in an open fire, or in the
most rudimentary form of potter's kiln, such pottery may be buff, drab,
brown or red--and these from imperfect firing become smoked, grey or
black. How many generations of men, of any race, handed on their
painfully acquired bits of knowledge before this earliest stage was
passed, we can never know; but here and there, where the circumstances
were favourable or the race was quick of observation, we can trace in
the work of prehistoric man in many countries a gradually advancing
skill based on increased technical knowledge. For ages tools and methods
remained of the simplest--the fingers for shaping or building up
vessels, a piece of mat or basket-work for giving initial support to a
more ambitious vase,--until some original genius of the tribe finds that
by starting to build up his pot on the flattened side of a boulder he
can turn his support so as to bring every part in succession under his
hand, and lo! the potter's wheel is invented--not brought down from
heaven by one of the gods to a favoured race, as the myths of all the
older civilizations or barbarisms, Egyptian, Chaldean, Greek, Scythian,
and Chinese have fabled, but born from the brain and hand of man
struggling to fulfil his allotted task.
Formerly every writer on the history of pottery seemed to imagine that
the very rudest pottery must have been the invention of Egyptian,
Chinese or some other distinct race from which the knowledge radiated to
all the other races of the prehistoric world. No conception could be
more erroneous. Since the middle of the 19th century research has
established beyond doubt that wherever clay was found men became potters
of a sort, just as they became hunters, carpenters, smiths, &c., by
sheer force of need and slowly-gathered tradition. The not yet exploded
view that Egypt or Assyria was the special cradle of this art, and that
the pottery of the Greeks and Romans directly descended from such a
parent stock, cannot survive in view of the incontestable evidence that
pottery was made by the prehistoric peoples of what we now call Greece,
Italy, Spain and other countries, long before they were aware that any
other peoples lived on the earth than themselves.
For centuries this simple hand-made pottery was hardened by drying in
the sun, so that it would serve for the storage of dried grain, &c., but
the increasing use of fire would soon bring out the amazing fact that a
baked clay vessel became as hard as stone. Then, too, came the knowledge
that even in one district all the clays did not fire to the same colour,
and colour decoration arose, in a rude daubing or smearing of some clay
or earth (a ruddle or bole perhaps), which was found to give a bright
red or buff colour on vessels shaped in a duller-coloured clay--most
precious of all were little deposits of white clay which kept their
purity unsullied through the fire,--and by these primitive means the
races of the dawn made their wares. On this substructure all the pottery
of the last four thousand years has been built, for behind all Egyptian,
Greek or Chinese pottery we find the same primitive foundations.
We now reach the beginnings of recorded history, and as the great
nations of the past emerge from the shadows they each develop the
potter's art in an individual way. The Egyptians evolve schemes of
glowing colour--brilliant glazes fired on objects, shaped in sand held
together with a little clay, or actually carved from rocks or stones;
the Greeks produce their marvels of plastic form, and then, excited by
their growing skill in metal work, turn the plastic clay into imitations
of metal forms. These nations are overthrown, and the Romans spread some
knowledge--only a tincture, it must be confessed--over all the lands
they hold in fee; and from the Euphrates to the Atlantic, from Egypt to
the Wall of Hadrian, they set alight potters' fires that have never
since been extinguished. The Roman empire falls, and over Europe its
pottery is forgotten along with its greater achievements; yet still
pottery-making goes on in a very simple way, to be slowly revived and
modified once more by the communities of monks, who, in later centuries,
replace the Roman legions as the great civilizing influence in Europe.
Meantime Egypt and the nearer East continued, in a debased form, the
splendours of their glorious past, and glazed and painted pottery was
still made by traditional methods. What part the Byzantine civilization
and the Persians played during this obscure time, we are only just
beginning to realize; but we now know that many interesting kinds of
decorated pottery were made at Old Cairo, at Alexandria, at Damascus, in
Syria, Anatolia and elsewhere (on which the later Moslem potters founded
their glorious works), at a time when all over Europe crocks of simple
red or drab clay, covered only with green and yellow lead-glazes, were
the sole evidence of the potter's skill. What the Arab conquests
destroyed, and what their breath quickened into life, we can only guess;
but the fact is indisputable that with the Mahommedan conquests there
came a time when the potter's art of the Occident reached its highest
expression, and when methods and knowledge hitherto confined to Egypt,
Syria and Persia were spread from Spain and the south of France to
India--even, it may be, into China.
Meantime, in the farther East, the Chinese--the greatest race of potters
the world has ever seen--were quietly gathering strength, until from
their glazed, hard-fired pottery there emerged the marvellous, white
translucent porcelain, one of the wonders of the medieval world.
With the dawn of the 15th century of our era, the state of affairs was
practically this:--In European countries proper we find rudely fashioned
and decorated wares in which we can trace the slow development of a
native craft from the superposition of Roman methods on the primitive
work of the peoples. The vessels were mostly intended for use and not
for show; were clumsily fashioned of any local clay, and if glazed at
all then only with coarse lead-glazes, coloured yellow or green; in no
case above the level of workmanship of the travelling brick- or
tile-maker. The finest expression of this native style is to be found in
the Gothic tile pavements of France, Germany and England, where all the
colours are due to the clays and there is no approach to painting. In
the Moslem countries--including the greater part of Spain and Sicily,
Egypt and the nearer East, probably even to the very centre of
Asia--pottery was being made either of whitish clay and sand, or of a
light reddish clay coated with a white facing of fine clay or of
tin-enamel, on which splendid decorative patterns in vivid pigments or
brilliant iridescent lustres were painted.
As early as the 12th century of our era this superior artistic pottery
of the Moslem nations had already attracted the notice of Europeans as
an article of luxury for the wealthy; and we may well believe the
traditional accounts that Saracen potters were brought into Italy,
France and Burgundy to introduce the practice of their art, while
Italian potters certainly penetrated into the workshops of eastern Spain
and elsewhere, and gathered new ideas. In Italy certainly, and in the
south of France probably, efforts were continuously in progress to
improve the native wares by coating the vessels with a white "slip" and
drawing on them rude, painted patterns in green, yellow and purplish
black. The increasing intercourse with Spain, in war and peace, also
introduced the use of tin-enamel after the fashion of the famous
Hispano-Moresque wares, and by the end of the 14th century a knowledge
of tin-enamel was widespread in Italy and paved the way to the glorious
painted majolica of the 15th and 16th centuries. From Italy and Spain,
France and Holland, Germany, and finally, though much later, England
learnt this art, and the tin-enamelled pottery of middle and northern
Europe, so largely made during the 17th and 18th centuries, was the
direct offshoot of this movement of the Italian Renaissance.[2]
During the 15th and 16th centuries Chinese porcelain also began to find
its way into Europe, and by the whiteness of its substance and its
marvellous translucence excited the attention of the Italian majolists
and alchemists. The first European imitation of this famous oriental
porcelain of which we have indubitable record was made at Florence
(1575-1585) by alchemists or potters working under the patronage, and,
it is said, with the active collaboration of Francesco de' Medici. This
Florentine porcelain was the first of those distinctively European
wares, made in avowed imitation of the Chinese, which form a connecting
link between pottery and glass, for they may be considered either as
pottery rendered translucent or as glass rendered opaque by shaping and
firing a mixture containing a large percentage of glass with a very
little clay. After the cessation of the Florentine experiments we know
of no European porcelain for nearly a century, though the importation of
Chinese porcelain had largely increased owing to the activity of the
various "India" companies. The next European porcelain, made like the
Florentine of glass and clay, was that of Rouen (1673) and St Cloud
(1696); and during the 18th century artificial glassy porcelain was made
in France and England largely, and in other countries experimentally.
German experimenters worked in another direction, and the first
porcelain made in Europe from materials similar to the Chinese was
produced at Meissen by Böttger (1710-1712). During the 18th century not
only was there a very large trade in imported Chinese and Japanese
porcelain, but there was a great development of porcelain manufacture in
Europe; and in every country factories were established, generally under
royal or princely patronage, for the manufacture of artificial porcelain
like the French, or genuine porcelain like the German. The English made
a departure in the introduction of a porcelain distinct from either,
through adding calcined ox-bones to the other ingredients; and this
English bone-porcelain--a well-marked species--is now largely made in
America, France, Germany and Sweden as well as in England.
By the end of the 18th century the risks and losses attendant on the
manufacture of the French glassy porcelain had caused its abandonment,
and a porcelain made from natural materials like the Chinese has since
been generally made on the continent of Europe.
The older tin-enamelled wares--derived from the Hispano-Moresque and the
Italian majolica--so largely made in France, Holland, Germany and
elsewhere during the 17th and 18th centuries, met with a fate analogous
to that of the French porcelain. Tin-enamelled earthenware is always a
brittle substance, soon damaged in regular use; so that, when, in the
middle of the 18th century, the English potter first appeared as a
serious competitor with a fine white earthenware of superior durability
and precision of manufacture, the old painted faience gradually
disappeared between the upper millstone of European porcelain and the
nether millstone of English earthenware.
The 19th century witnessed a great and steady growth in the output of
porcelain and pottery of all kinds in Europe and the United States.
Mechanical methods were largely called in to supplement or replace what
had hitherto remained almost pure handicraft. The English methods of
preparing and mixing the materials of the body and glaze, and the
English device of replacing painted decoration by machine printing, to a
large extent carried the day, with a great gain to the mechanical
aspects of the work and in many cases with an entire extinction of its
artistic spirit. Even the hand-work that still remained was largely
affected by the growing dominance of machinery; and the painting,
gilding and decoration of pottery and porcelain, in the first half of
the 19th century, became everywhere mechanical and hackneyed. During the
latter half of the 19th century another influence was fortunately at
work. Side by side with the increasing mechanical perfection of the
great bulk of modern pottery there grew up a school of innovators and
experimentalists, who revived many of the older decorative methods that
had fallen into oblivion and produced fresh and original work, in
certain directions even beyond, the achievements of the past. The 20th
century opened with a wider outlook among the potters of Europe and
America. In every country men were striving once again to bring back to
their world-old craft something of artistic taste and skill.
_Technical Methods._--All primitive pottery, whether of ancient or of
modern times, has been made by the simplest methods. The clay, dug
from the earth's surface, was or is prepared by beating and kneading
with the hands, feet or simple mallets of stone or wood; stones and
hard particles were picked out; and the mass, well tempered with
water, was used without any addition. From this clay, vessels were
shaped by scooping out or cutting a solid lump or ball, by building up
piece by piece and smoothing down one layer upon another or by
squeezing cakes of clay on to some natural object or prepared mould or
form. The potter's wheel, though very ancient, was a comparatively
late invention, arrived at independently by many races of men. In its
simplest form it was a heavy disk pivoted on a central point to be set
going by the hand, as the workman squatted on the ground; and it may
be seen to-day in India, Ceylon, China or Japan, in all its primitive
simplicity (see fig. 1). This form of potter's wheel was the only one
known until about the Christian era, and then, in Egypt apparently,
the improvement was introduced of lengthening the spindle which
carries the throwing-wheel and mounting on it near the base a much
larger disk which the potter could rotate with his foot, and so have
both hands free for the manipulation of the clay (fig. 2). No further
advance seems to have been made before the 17th century, when the
wheel was spun by means of a cord working over a pulley; and though a
steam-driven wheel was introduced in the middle of the 19th century,
this form remains the best for the production of fine pottery.
[Illustration: FIG. 1.--Potter moulding a vessel on the wheel (from a
painting in a tomb at Thebes about 1800 B.C.). Compare the wheel on
the left in fig. 5.]
[Illustration: FIG. 2.--Potter's wheel of the time of the Ptolemies,
moved by the foot (from a wall-relief at Philae). Compare fig. 5, the
wheel on the right.]
A prevalent misconception with regard to the potter's wheel needs
correction. For anything beyond very simple shapes it is impossible to
carry the work to completion on the wheel at one operation as is
generally imagined. All that the potter can do while the clay is soft
enough to "throw" on the wheel is to get a rough shape of even
thickness. This operation completed, the piece is removed from the
wheel and set aside to dry. When it is about leather-hard, it may be
re-centred carefully on the wheel (the old practice), or placed in a
horizontal lathe (since 16th century) and turned down to the exact
shape and polished to an even, smooth surface. The Greek vase-makers
were already adepts in what is often reckoned a modern, detestable
practice. Many Greek vases have obviously been "thrown" in separate
sections, and when these had contracted and hardened sufficiently they
were luted together with slip, and the final vase-shape was smoothed
and turned down on the wheel, and even polished to as fine a degree of
mechanical finish as the modern potter ever attains. So too with the
Chinese; many of their forms have been made in two or three portions,
subsequently joined together and finished on the outside as one piece.
Indeed it is remarkable how the Greeks and Chinese had discovered for
themselves many devices of this kind which are generally held up to
opprobrium as the debased methods of a mechanical age. Always it
should be borne in mind that the shaping of pottery by "pressing"
cakes of clay into moulds is much older than the potter's wheel, and
has always been the method of making shapes other than those in the
round. The modern method of "casting" pottery by pouring slip, a fluid
mixture of clay and water, into absorbent moulds seems to have
originated in England about the middle of the 18th century; and this
too is a genuine potter's method which does not merit the disapproval
with which it has been generally regarded by writers on the potter's
art.
In all ages the work of the "thrower" or "presser" has been largely
supplemented by the modeller, who alters the shape, and applies to it
handles, spouts or modelled accessories at will.
[Illustration: FIG. 3.--Early Greek pottery-kiln, about 700-600 B.C.
(from a painted votive tablet found at Corinth, now in the Louvre).
The section shows the probable construction of the kiln.]
[Illustration: FIG. 4.--Roman kiln found at Castor. The low arch is
for the insertion of the fuel; the pots rested on the perforated
floor, made of clay slabs; the top of the kiln is missing,--it was
probably a dome.]
_Firing._--The firing of pottery has become in modern times such a
specialized branch of the manufacture that the student can only be
referred here to the technological works mentioned in the bibliography
at the end of this article. It is, however, necessary that we should
briefly describe the earlier forms of potters' kilns used by the
nations whose pottery counts among the treasures of the collector and
the antiquary. Here again we now know that the primitive types of kiln
used by the potters of ancient Egypt or Greece have not vanished from
the earth; it is only in the civilized countries of the modern world
that they have been replaced by improved and perfected devices. The
potters of the North-West Provinces of India use to-day a kiln
practically identical with that depicted in severest silhouette on the
rock-tombs of Thebes; and the skilful Japanese remain content with a
kiln very similar to the one shown in fig. 3. This Greek type of kiln
was improved and enlarged by the Romans, and its use seems to have
been introduced wherever pottery was made under their sway, for
remains of Roman kilns have been found in many countries (see fig. 4).
With the end of Roman dominance we have ample evidence that their
technical methods fell into disuse, and the northern European potter
of the period from the 6th to the 12th century had to build up his
methods afresh, and improved kilns were invented. The general type of
medieval potter's kiln is illustrated for us in the manuscript of an
Italian potter of the 16th century, now in the library of the Victoria
and Albert Museum[3] (fig. 5). Kilns of a different type, horizontal
reverberatory kilns, were used for making the hard-fired pottery of
Europe (Rhenish stoneware, &c.), as well as for Chinese porcelain and
the earliest German porcelains. With the organization of pottery as a
factory industry in the 18th century, improved kilns were introduced,
and the type of kiln now so largely used in civilized countries is
practically a vertical reverberatory furnace of circular section, from
10 to 22 ft. in diameter and of similar height, capable, therefore, of
containing at one firing a quantity of pottery that would have formed
the output of a medieval potter for a year. Every device that can be
thought of for the better utilization of heat and its even
distribution throughout the kiln or oven has been experimented with;
and, though the results have been most successful from the point of
view of the potter, even the most recent coal-fired ovens remain very
wasteful types of apparatus, the amount of available heat being
relatively small to the fuel consumption. Gas-fired kilns and ovens
are now being used or experimented with in every country, and their
perfection, which cannot be far distant, will improve the most vital
of the potter's processes both in certainty and economy.
[Illustration: FIG. 5.--Two forms of Italian potter's wheels, about
1540.]
_Glazes._--We are never likely to known when glaze (i.e. a coating of
fired glass) was first applied to pottery, though the present state of
knowledge would incline us to the opinion that the earliest glazed
objects we possess are those of ancient Egypt,[4] but the practice may
have been originated independently wherever a knowledge of the
elements of glass-making had spread, as all the early glazes were of
the alkaline type, which must first be fused into a glass before they
can be applied to pottery.
Many primitive races seem to have burnished their pottery after it was
fired, in order to get a glossy surface; and in other cases the
surface was rendered shining and waterproof by coating it with waxy or
resinous substances which were often coloured. It is possible that the
black varnish of Greek vases was obtained by such a method, and though
that point is not settled, we have many types of primitive pottery,
both modern and ancient, which are coated in this way. Such a coating
is only a substitute for glaze in the work of peoples who do not know
or have not mastered the technical secrets of true glazes. We can only
consider as glazes those definite superficial layers of molten
material which have been fired on the clay substance. Glazes are as
varied as the various kinds of pottery, and it must never be forgotten
that each kind of pottery is at its best with its appropriate glaze.
The earliest known glazes (Egyptian and Assyrian) were silicates of
soda and lime containing very little alumina and no lead. Such glazes
are very uncertain in use, and can only be applied to pottery
unusually rich in silica (i.e. deficient in clay). Consequently these
alkaline glazes cannot be used on ordinary clay wares, and when they
have been used successfully, the clay has always been coated with a
surface layer of highly siliceous substance (e.g. the so-called
Persian, Rhodian, Syrian and Egyptian pottery of the early middle
ages). The fact that glazes containing lead-oxide would adhere to
ordinary pottery when alkaline glazes would not was discovered at a
very early period; for lead glazes were extensively used in Egypt and
the nearer East in Ptolemaic times, and it is significant that, though
the Romans made singularly little use of glazes of any kind, the
pottery that succeeded theirs, either in western Europe or in the
Byzantine empire, was generally covered with glazes rich in lead.
Throughout Europe, and over the greater part of the world, leaded
glazes have been continuously used and improved for all ordinary
pottery, and it is only with certain special hard-fired types of ware
that they have yet been successfully replaced. Chinese porcelain and
all the European porcelains made by analogous methods are fired at so
high a temperature that a glaze by felspar softened by lime and silica
is found most suitable for them, and the hard-fired stonewares, rich
in silica, are often glazed with a salt glaze, or a melted earth rich
in oxide of iron.
Every kind of potter's clay (the mixture of clay, sand, flint, &c.,
from which the potter shapes his wares) has its own type of glaze, and
from the earliest time down to our own what the potter could produce
in form or glaze or colour has been largely decided for him by the
clay material at his command. With any good plastic clay which cannot
be fired at the highest temperature, lead glazes have always proved
the most practicable. A similar clay, to which large quantities of
sand are added, may be glazed by the vapours of common salt; and
mixtures rich in felspar, like Chinese or European porcelain, can be
glazed by melting felspathic materials upon them. Naturally those
species of pottery which are the hardest fired are the most
durable--the glazes of hard porcelain are more unchangeable than lead
glazes, and these in their turn than alkaline glazes.
The most important types of glaze are (1) alkaline glazes (e.g.
Egyptian, Syrian, Persian, &c.), the oldest and most uncertain; (2)
lead glazes, the most widespread in use and the best for all ordinary
purposes; (3) felspathic glazes, the glazes of hard-fired porcelains,
generally unsuited to any other material; (4) salt glaze, produced by
vapours of common salt, the special glaze of stonewares. Many
intermediate glazes have been devised to meet special needs, but these
remain the only important groups. Fuller details on this important
subject must be sought in the technical works.
_Colours._--The primitive potters of ancient and modern times have all
striven to decorate their wares with colour. The simplest, and
therefore the earliest, colour decoration was carried out in natural
earths and clays. The clays are so varied in composition that they
fire to every shade of colour from white to grey, cream, buff, red,
brown, or even to a bronze which is almost black. One clay daubed or
painted upon another formed the primitive palette of the potter,
especially before the invention of glaze. When glaze was used these
natural clays were changed in tint, and native earths, other than
clays, containing iron, manganese and cobalt, were gradually
discovered and used. It is also surprising to note that some of the
very earliest glazes were coloured glasses containing copper or iron
(the green, turquoise and yellow glazes of the ancient Egyptians and
Assyrians). Marvellous work was wrought in these few materials, but
the era of the finest pottery-colour dawns with the Persian, Syrian
and Egyptian work that preceded the Crusades. By this time the art of
glazing pottery with a clear soda-lime glaze had been thoroughly
learnt. Vases, tiles, &c., shaped in good plastic clay, were covered
with a white, highly siliceous coating fit to receive glazes of this
type, and giving the best possible ground for the painted colours then
known. With this rudimentary technique the potters of the countries
south and east of the Mediterranean produced, between the 9th and 16th
centuries of our era, a type of pottery that remains ideal from the
point of view of colour: for, with nothing more than the greens given
by oxide of copper and iron, the turquoise of pure copper, the deep
yet vivid blue of cobalt, the beautiful uncertain purple of manganese,
and in certain districts the rich red of Armenian bole, they achieved
colour schemes that have never been surpassed in their brilliant yet
harmonious richness.
When the coating of white siliceous clay was replaced by an opaque
tin-enamel as in Spain, Italy, France, Holland, &c., a necessary
change in the colour schemes resulted. At first only the copper-greens
and cobalt-blues could be used on such a ground; the fine manganese
purple turned to brown or black and the rich iron-reds to filthy
shades of yellow. We cannot wonder that the Spanish-Arab potters paid
more attention to their lustre decoration, for that was the natural
thing to do. How strong and fine a palette could be evolved for use on
a tin-enamel ground was shown by the Italian majolists of the 15th and
16th centuries; and when the later developments of tin-enamelled
pottery took place in France, Holland, Germany, &c., their colour
schemes are only echoes of Italian majolica crossed with Chinese
porcelain. Delft, Nevers, Moustiers and Rouen may each charm us with
its individuality; Nuremberg and other south German towns may show us
that they too had mastered the use of tin-enamel; yet our minds always
go back to the colour schemes of Italian majolica and of the Persian
and Syrian pottery that lie behind and beyond them.
The colours already spoken of were either clay colours or what are
known as "under glaze" colours, because they were painted on the
pottery before the glaze was fired.
The earliest glazes of the Egyptians appear not to have been white,
but were coloured throughout their substance, and this use of coloured
glazes as apart from painted colour was developed along with the
painted decoration by the later Egyptian, Syrian and Persian potters.
Green, yellow and brown glazes were almost the only artistic
productions of the medieval European potters' kilns, and their use
everywhere preceded the introduction of painted pottery. The most
extensive application of coloured glazes was, however, that made by
the Chinese, who developed this type of colour decoration before they
used painted patterns in underglaze colour. The earliest Chinese
porcelains, and the hard-fired stonewares out of which their porcelain
arose, were decorated in this way, and the beauty of many of the early
Sung coloured glazes has never been surpassed.
With the exceedingly refractory felspathic glazes of Chinese porcelain
very few underglaze colours could be used; and the prevalence of blue
and white among the early specimens of Chinese porcelains is due to
the fact that cobalt was almost the only substance known to the
potters of the Ming dynasty which would endure the high temperature
needed to melt their glazes. Consequently the Chinese were driven to
invent the method of painting in coloured fusible glasses on the
already fired glaze. They adopted for this purpose the coloured
enamels used on metal; hence the common term "enamel decoration,"
which is so generally applied to painting in those colours which are
attached to the already fired glaze by refiring at a lower
temperature. With the introduction of this many-coloured Chinese
porcelain into Europe the same practice was eagerly followed by our
European potters, and a new palette of colours and fresh styles of
decoration soon arose amongst us. Painting in on-glaze colours, being
executed on the fired glaze, resembles glass painting, and it
generally offers a striking contrast both in technique and
colour-quality to the painting executed in colours under the glaze. In
the former the work can be highly finished and the most mechanical
execution is possible, but the colours are neither so rich nor so
brilliant as under-glaze colours, nor have they the same softness as
is given by the slight spread of the under-glaze colour when the glaze
is melted over it.
It must be pointed out that the colour possibilities in any method of
pottery decoration are largely dependent on the temperature at which
the colour needs to be fired. The clay colours are naturally more
limited in range than the under-glaze colours, and these in their turn
than the on-glaze colours.
When, about the middle of the 18th century, European pottery took on
its modern form, of earthenware made after the English fashion, and
porcelain like the French and German, the lead or felspathic glazes
used brought about another revolution in the potter's palette. The
growing ideal of mechanical perfection discounted the freedom of the
earlier brushwork, and printed patterns, or painting that might almost
have been printed, removed the mind still farther from the richness of
painted faience or majolica. It is useless to look for the glorious
colour of Persian faience, Italian majolica, or Chinese porcelain, in
modern wares produced by manufacturing processes where mechanical
perfection is demanded to a degree undreamt of before the 19th
century. The finest modern pottery colour is only to be sought in the
work of those enthusiasts and experimenters who are striving to
produce work as rich and free as the best of past times.
_Metals_.--The noble metals, such as gold, platinum and silver, have,
since the early years of the 18th century, been largely used as
adjuncts to pottery decoration, especially on the fine white
earthen-wares and porcelains of the last two centuries. At first the
gold was applied with a kind of japanner's size and was not fired to
the glaze, but for the last 150 years or so the metals have generally
been fired to the surface of the glaze like enamel colours, by mixing
the metal with a small proportion of flux or fusible ground glass.
There can scarcely be a doubt that the ancient lustres of Persia,
Syria and Spain were believed to be a form of gilding, though their
decorative effect was much more beautiful than gilding has ever been.
The early Chinese and Japanese gilding appears, like the European, to
have been "sized" or water-gilt, not fired; and it seems probable that
the use of "fired" gold was taught to the Oriental by the European in
the 18th century. To-day "liquid" gold is exported to China and Japan
from Europe for the use of the potter.