of pottery, but it is also the most critical one. The supreme test of
the potter’s work is to subject it to the fire, for many forms of
accident occur during the process, some of them due to careless handling
of the vessels or of the firing materials, others to defective
workmanship or to hidden flaws in the paste. It is only natural that the
potters should exhibit considerable excitement and nervousness during
the firing. Some women proceed calmly and methodically, and take
occasional accidents as part of the day’s work; others are exceedingly
nervous, and show exasperation when things go wrong. The latter, as a
rule, have more accidents than the former. One potter, in six burnings,
lost two large ollas through breakage, and had innumerable smoke-clouds,
several of them rather severe ones.
The firing falls naturally into four distinct phases: the preparation,
the building of the oven, the burning, and the treatment after burning.
Each of these phases will be considered separately.
PREPARATION
The oven is usually situated behind the potter’s house. All that is
required is a level space free from vegetation; no attention is paid, as
a rule, to the position of the sun or to the direction of the prevailing
wind, and the same spot is used time after time. If on the evening
before the firing there are any signs of rain, or if a heavy dew is
expected, the area on which the oven is to be built in the morning is
covered with a thick layer of dead ashes to protect it from moisture. It
would be a fatal mistake to make the oven on ground which would give off
steam during the burning.
About six o’clock the next morning a fire is started on the area over
which the oven is to be built. While this preliminary fire is thoroughly
drying the ground, the accessories are collected (pl. 24, a). Slabs of
dung are brought out from the storage places; some of them are placed
against the house wall to dry in the sun, others remain in the washtubs
in which they have been carried. The material for the grate, and other
iron bars, are placed nearby. Pokers of wood and iron, shovels, and
sometimes pitchforks, which are to be used later in handling the burning
fuel and hot vessels, are placed within reach. When a collection of
small tin cans, pail-tops, and small stones saved for this purpose has
been added, the workers are ready to begin the burning. Usually a supply
of cedar kindling has been split, but sometimes this is done as the wood
is needed.
BUILDING THE OVEN
When the preliminary fire has died down to a mass of coals, these are
levelled to form an area of hot ashes about three feet in diameter. On
this the oven is built. The surface upon which the vessels are placed
must be raised a few inches
[Illustration: PLATE 24
a. Drying the oven site with a preliminary fire before burning the
pottery. At the lower right-hand corner are an old iron grate which will
later support the vessels, two iron rods to hold up the roof of the
oven, and a wooden poker. Cakes of dung for the oven walls are drying in
the sun against the house.
b. The vessels on the grate, and the oven wall of dung cakes begun.
Small tin cans support the cakes and keep them from touching the
vessels. The grate rests on stones, and split cedar kindling is placed
below it on the embers of the preliminary fire.]
above the ground to permit the introduction of fuel below the pottery.
Such a surface is usually formed of iron rods of one kind or another.
One potter built up a grate of a varied assortment of iron junk
supported on tin cans and odd-shaped iron fragments. Another potter used
a worn-out stove-grate supported on four half-bricks.
The vessels are then placed upon the grate in an inverted position. No
attempt is made to keep them from touching one another. In fact, they
are crowded together in order that the greatest possible number may be
burned at once (pl. 24, b). In firing red ware and polychrome ware only
one layer of vessels is placed upon the grate. When polished black ware
is to be burned, two layers may be made. The vessels in the second layer
are always placed carefully between those of the bottom layer, in order
that there may be free circulation of air on both the interior and
exterior of all the vessels (pl. 25, a). As a rule the larger bowls are
placed in the lower layer.
The number of polychrome vessels burned at one time varies from
half-a-dozen to twenty, according to the area of the grate and the size
of the vessels. At one burning there were eleven pieces, eight
medium-sized and three small; in another there were twenty, eight of
which were medium-sized, and the other twelve very small. It is possible
to burn as many as thirty-five polished black bowls at once. Some
potters burn both polychrome and red pottery in the same oven; others
insist that this should not be done, because red ware requires far less
time and heat than does polychrome.
After the pots have been placed on the grate, pieces of split cedar six
to fifteen inches long are inserted underneath it. Piñon is never used,
but the potters could not explain this, saying they had never tried it.
A wall-like ring of dung-cakes, placed on edge but not set as snugly
together as they might be, is then built around the grate (pl. 25, b).
Small tin cans, held in place by the weight of the dung, are used to
prevent the cakes from touching the vessels (pi. 24, b, shows one of
these cans very clearly). Sometimes small stones and broken bricks are
used in place of cans. While the ring is being completed more kindling
may be added. The Zuñi oven differs from that of San Ildefonso in being
built of smaller pieces of manure which are laid up horizontally instead
of on edge (see pl. 31, b, c).
The fire may now be lighted before the oven is finished, but sometimes
the potters wait until the roof is nearly complete. Cedar-bark shreds
are generally used to start the fire. The lighting is done through the
spaces between the dung-cakes, usually at more than one place, sometimes
in as many as five. No attention is paid to the wind in this process. If
the fire does not start quickly enough, cloths are used to fan the
flames.
The roof or vault of the oven is then built. Some potters place iron
bars across the top of the dung-ring, keeping them from touching the
vessels by inserting tin cans and stones. On these bars flat cakes of
dung are laid, and the larger holes are covered with smaller pieces of
dung. Other potters dispense with the bars and rest a large circular
cake of dung upon cans and stones set in the centre of the pile of
pottery. The space between this central cake and the top of the
dung-ring is bridged by other cakes which rest on the dung alone. In
this manner a low vault of dung-slabs is formed, roughly square in
shape, two and a half to three feet on a side, and about a foot and a
half high (pl. 25, c). There are still left numerous spaces, both large
and small, between the cakes. These are covered with smaller pieces of
dung, and with old tin tops of lard-pails or discarded tin plates (pl.
26, a). Even after this, however, there remain enough small spaces to
allow free circulation of air, and to prevent the smothering and
consequent smoking of the vessels. Through these smaller spaces the
flames and pots may be seen. The building of the oven is now complete;
by this time the fire has usually been started, and the flames are well
under way.
As a rule more than one burning is undertaken during a morning. The
building of the oven for the second burning differs slightly in its
preliminary stages from that described above. After the previous oven
has been destroyed, the ashes are smoothed out, and the grate set
straight and carefully dusted so that no ashes remain (pl. 26, b). The
bowls are than placed on it as before. Partly burned cakes of dung,
which remain from the first burning, are re-used. If, in placing them on
the oven, ashes drop on the vessels, care is taken to blow them off.
Some potters stand the vessels which are to be burned on the warm cakes
of dung for a few minutes before placing them on the grate (pl. 26, b),
a process which is supposed to heat them slightly and thus prevent
breakage during firing. Other potters would not think of doing this, for
vessels treated in this manner always have discolored bases, where the
warm dung has touched them.
Ollas twelve to fourteen inches in diameter are burned in pairs, with a
few smaller pieces beside them. The oven is built in the same manner as
before. Very large ollas are usually fired one at a time; the oven,
except for its greater size, is said to be of the usual type.
BURNING
As was said above, the firing of the pottery is done in the morning. The
Indians say that they wish to get it over with “before the sun grows
hot”. Their own personal comfort probably plays a more important part in
this than does the effect of the sun upon the pottery. As a rule the
firing is withheld until a sufficient number of finished vessels have
accumulated to permit three or four burnings in one morning. The entire
forenoon is spent at this work, and sometimes it drags over until early
afternoon. The actual burning of the vessels occupies a period of about
half-an-hour for each oven; it is said that the length of time has not
been appreciably shortened in the past forty or fifty years. The black
ware is always saved for the last oven, since the process employed
completely precludes the possibility of rebuilding the oven at once.
At the beginning of the burning white smoke is apt to be given off, but
too much smoke is regarded as a bad sign, since it signifies that the
dung cakes are not sufficiently dried. After fifteen minutes or so, that
is when the process is about half finished, the amount of smoke has
greatly diminished (pl. 26, a). About this time more kindling is added
through openings made by temporarily removing a piece of tin, and new
cakes of dung are added where necessary, usually on the top of the oven.
The Indians say that they judge of the condition of the pottery in the
oven by its color; the paste and slip must be of just the proper shade
before the vessels are
[Illustration: PLATE 25
The building of an oven. a. A double layer of bowls is on the grate; the
woman is placing a can between a dung-slab and a bowl. b. The wall of
dung-cakes completed. c. The oven finished, but the chinks not yet
filled.]
[Illustration: PLATE 26
a. The oven fired. The chinks between the dung-slabs have been partly
closed by smaller pieces of dung. b. A firing completed and a grate
prepared for a second firing. Two vessels to be burned are warming on
hot dung-slabs; the pots that have just been taken from the fire are
cooling in the shadow of the house.]
thoroughly burned; if they are too dark the burning must continue.[49]
Some potters seem to pay little or no attention to the color of the
vessels in the oven.
When the potter considers that the burning has been completed, the cakes
of dung on the top of the oven are lifted off with a pair of pokers, and
those in the ring around the grate are tipped outward. Thus the vessels
on the grate are exposed, and their removal is begun at once. Some are
tipped on shovels or hay forks; pokers are inserted under and into
others. They are then deposited upon tins which have been placed on the
ground within six or eight feet of the oven, and are left there from ten
to twenty minutes to cool. The women often complain about the heat from
the oven during the removal of the vessels. As soon as the grate has
been cleared, preparations are begun for the next burning (pl. 26, b).
In one instance a potter decided that a certain vessel which had been
removed from the grate was not sufficiently burned. Another fire was
already in progress, but when the third was built the vessel was
replaced on the grate and burned again. When it came out, however, one
side was badly overfired.
The time occupied by various burnings is given in the following table.
The first four columns represent burnings by Maria Martinez; the last
three by Antonita Roybal. The seventh column records the oven in which
the partly fired piece was reburned, and in which a cooking vessel was
also placed.
TABLE X
(1) (2) (3) (4) (5) (6) (7)
_Minutes_
Preparation and building of oven begun 00 00 00 00 00 00 00
Fire started 25 15 06 12 15 15 09
More kindling and dung added 45 25 25 57
Oven broken up 52 37 36 41 72 40 27
Last bowl removed from grate 58 41 42 47 77 45 30
The time required for burning the different wares varies only slightly.
Some potters say that red ware takes less fuel, less heat, and less time
than polychrome ware; others place both wares in the same oven. The
difference in the time required for these two wares is probably no
greater than the chance variations in the length of burning as given in
Table X. Cooking vessels need to be fired only from one-half to
two-thirds as long as the two wares just mentioned (cf. Table X, column
7). The polished black ware will be considered later.
The changes in color before and after firing, and when hot and cool, are
very noticeable in some pigments and slips. The orange-red paint is
yellow before firing, firing turns it orange-red, almost the color of
burnt sienna; cooling produces no noticeable change in this shade.
Burning has only a fugitive effect on the red and dark-red slips. While
still hot, upon removal from the oven, these are both a dark chocolate
shade. As the vessels cool the different reds gradually reappear, until
when cold they are the same color as before firing. In some cases, these
pigments seem to be just a shade darker after firing than before. The
two kinds of white slip are a dead white when applied; after firing they
take on a slight pinkish-brown tinge, more cream than white. Cooling
produces no further change.
The most interesting change caused by firing is in the black vegetable
pigment (guaco). It has already been pointed out (p. 66), that when this
paint is laid on thickly, the line made is a little raised and glossy,
like a glaze. This “body” to the paint is probably formed by vegetable
matter in suspension in the solution. When the vessels with such
decorations are removed from the oven after burning, these lines are
seen to be white or grey. The material which formed the body of the
pigment has been reduced to white ash, which adheres to the surface, but
can be rubbed off with the finger or a cloth, while the black color
itself has been burned into the clay. Where a thin layer of the pigment
was applied, the line, after burning, is light grey, because the black
under the thin coat of ash shows through. In those vessels on which a
thick solution of pigment was used, the decorations are dead white, and
the surface of the ash is often crackled. The thickness of this ash
seems to have some effect upon the manner in which the black pigment is
burned into the clay, for in decorations covered with a thick layer of
ash, the black is of an irregular color with streaks of grey in it. When
the thin pigment is used, the resulting black on the finished vessel is
of a uniform shade. The glossiness and raised character of the pigment
is of course completely destroyed during burning. Guaco lines do not
change in shade while the vessel is cooling.
The color of the paste is little affected by burning. In both the red
and the white clays, the change is simply one of tone, that is, the clay
is lighter after burning than before. The cooking-vessel clay before
burning is greyish yellow, but after it has been removed from the oven
it is a rich orange-yellow. These cooking vessels eventually become
blackened by use over an open fire.
Vessels destined to be polished black ware are treated in quite a
different manner during the firing stage, for they are to be subjected
to a smothered fire, which will result in the deposition of carbon, thus
turning them from red to black. The oven is built in the same way, but
greater care is taken to fill gaps, so that more of the heat may be
retained. Enough spaces remain, however, to permit free circulation of
air. More kindling is used, for a hotter fire is necessary. When the
fire has reached the stage at which other wares are removed, it is
smothered with new, pulverized, loose manure. Just before the smothering
the vessels have the dark chocolate color typical of the red wares while
hot. The potter always attempts to smother the entire oven at once by
dumping upon it a whole washtubful of fine loose manure. If there is a
wind, flames are apt to break out in one or two places. They are,
however, hurriedly extinguished. When the loose manure is added, the
arch of the oven is, of course, broken, and both cakes and loose manure
come in contact with the vessels. For this reason the potter does not
exercise particular care in building the oven to keep the cakes from
touching the vessels, as they are to be entirely black in the end and a
little premature smoking does no harm. After the manure has been added,
the mound is continually prodded with a poker to redistribute the loose
manure and make certain that all the pieces are equally covered. An
extra supply of loose manure is at hand, and this is added in large and
small quantities from time to time, as occasion demands. Two washtubsful
are generally used, sometimes three. The mound of manure gives off a
dense white smoke after the smothering has begun (pl. 27, a). Great care
is taken to prevent flames from appearing, since these would remove the
carbon from the vessel.
[Illustration: PLATE 27
a. A fire smothered with loose manure to produce polished black ware. b.
Wiping vessels that have become cool enough to handle. One woman wipes
off the ashes with a dry rag, then passes them to her companion, who
goes over them with a slightly greasy cloth.]
Ten or fifteen minutes after the smothering the first piece is dug out
of the mound with the poker. It is placed a foot or two from the oven
and hastily wiped with a dry cloth to remove all manure. The surface of
the vessel is a beautiful shiny black color, which does not change at
all on cooling. If black ware paint (see p. 24) has been used, it
changes from the greenish-yellow color that it had before burning to a
dead matte black which contrasts very effectively with the polished
surface of the vessel (see pl. 8, a). At first the vessels come from the
smoking mound slowly, and all holes left in the pile by the removal of
vessels are carefully filled again, but later they are taken out as
quickly as possible, and toward the end no attempt is made to keep the
pieces still in the pile thoroughly covered. If, when a vessel is
removed, its condition does not quite suit the potter, it is replaced in
the smoking manure and completely covered.
Certain polished black vessels are further manipulated in such a way as
to produce an irregular red blotch upon them.[50] Specimens destined to
receive this red blotch, which is usually placed near the rim, are
reburied in the hot manure lying round the edge of the pile with that
portion which is to have the blotch left uncovered. Against this exposed
portion is placed a smoking fragment of a dung-slab. The action of the
heat and air results in the removal of the carbon from the surface, so
that that part of the vessel which is not covered with manure and ashes
regains its former color, the red of the pigment. Since the pot is
pushed about a good deal during this process, the line between the red
and the black surface is not always very definite, which improves the
appearance. The Indians themselves cannot tell beforehand just what
shape the blotch is going to take, and must therefore watch the vessel
continually. Sometimes burning shreds of cedar bark are placed against
the exposed surface to hasten the process, but actual flames are not
necessary in order to obtain the desired result. If the red blotch is
too large, part of it is simply recovered with hot manure-ashes, and a
few minutes later will again become jet black. So far as looks are
concerned the success or failure of this red blotch upon black ware
depends largely upon the artistic sense of the potter making it. In one
group of thirty-three polished black vessels fired together, sixteen
were given a red blotch; eight or ten of these were excellent pieces.
The time consumed in burning polished black ware is shown in Table XI.
It should be noted that before the loose manure was added, the vessels
were subjected to the fire about the same length of time as those of
other wares.
TABLE XI
_Minutes_
Preparation and building of oven begun 00 00
Fire started 16 18
More fuel added 41 39
Oven smothered with loose manure 46 45
First bowl removed 59 59
Last bowl removed 74 99
ACCIDENTS
The accidents which may occur in firing are of two general
classes--those which result from faulty treatment during the
construction of the vessel itself and those which are due to careless
manipulation in burning. The latter are the more frequent.
A vessel may crack or flake badly in the oven; often the entire base
breaks off. The fault in this case lies in the original moulding,
because small stone fragments or air-bubbles were allowed to remain
embedded in the paste. Since the rate of expansion under heat varies for
different substances, a great strain develops about such stones or
air-bubbles during firing, and the natural result is cracking or flaking
of the clay. In some larger vessels the slip flakes away around the
shoulder, where the two areas of the surface met when the polishing was
done (see p. 64). In the potter’s opinion these flakes, which are
exceedingly small, are probably caused by minute air-bubbles that had
lodged under the slip while the line about the shoulder was being
polished. A third type of accident is merely a blemish; it is due to
flies settling on a vessel before burning; the resulting fly-specks are
burned into the clay, and the surface of the pot is sprinkled with dots
quite as black as guaco decorations.
The most common form of blemish caused by careless manipulation during
firing is the “smoke-cloud” or “fire-cloud”, a circular blackened area,
the darkest part of which is at the centre. There is no question but
that this is caused by contact between the vessel and a dung-cake, and
the result is probably due to moisture in the dung which brings about a
deposit of carbon on the surface. If, during the burning, a cake of dung
falls, it will probably come in contact with the surface of some bowl.
If it is removed at once there is little danger of a smoke-cloud, and
the potter, when she notices such an accident, immediately tries to
secure the fallen cake with two pokers. With much skill she carefully
extricates it from within the oven without disturbing the other cakes
about the place from which it fell. Fire-clouds may be produced upon the
bases of vessels by setting them on hot cakes of dung before firing; or
upon damp, or relatively damp, ground immediately after firing.
Excessive dampness, such as steam from wet ground under the oven, may in
addition to discoloration, produce warping of the vessels. Another sort
of blemish is occasionally caused by rust from a tin can resting upon a
vessel during firing; such a spot is usually reddish brown in color, and
covers a very small area.
If light areas appear on polished black ware, it is safe to assume that
they were brought about by lack of proper ventilation within the oven
during the preliminary burning, such as would occur if two vessels were
so close together as to prohibit the free passage of air. If white slip
is touched just before burning, the oil from the fingers is apt to be
fired in, thus ruining the uniform appearance of the surface by the
potter’s indelible fingerprint. To avoid such an accident, polychrome
vessels are usually handled only by the interior of the rim on the day
they are burned.
Underfiring and overfiring, with consequent damage to the ware, are
usually due to gross carelessness on the part of the potter in the
irregular placing of kindling. The wind also has something to do with
it. If there is a stiff breeze blowing, the probabilities are that the
windward surfaces of vessels within the oven will be underfired, while
those in the lee of the vessels will be overfired.
[Illustration: PLATE 28
_Courtesy Amer. Mus. Nat. Hist._
ZUÑI. PREPARING CLAY
a. Pulverizing dry ingredients on flat stone slab with a _mano_ or hand
stone.
b. Wetting, mixing, and kneading clay; water-container in foreground;
prepared clay in bowl.]
[Illustration: PLATE 29
_Courtesy Amer. Mus. Nat. Hist._
ZUÑI. MOULDING
a. Lower part of vessel completed; potter forming roll of clay with
which to continue building.
b. Applying roll of clay; left hand guides roll; right hand welds it to
side of vessel.]
[Illustration: PLATE 30
_Courtesy Amer. Mus. Nat. Hist._
ZUÑI. SURFACING