liERAMIC STUDIO 
31 
is black in reducing, yellow in oxidising, etc. The limited 
space for these articles does not allow me to give the scientific 
reasons for these pyrochemical combinations. 
Through the handling of the chimney damper and of the 
plaques on the fire mouths (Fig. 89 and go), it will be easy to 
put into practice the theory which I hav'^e just explained. 
These fire mouth plaques are of the same material as the saggers 
but fired in the hottest part of the kiln. They must haA^'e the 
same length as the hopper of the fire mouth, and be half as 
broad as long. 
The characteristics of a reducing atmosphere are, inside, 
flame striated with waves of soot which dim the view, and 
outside, on top of the cliimney, a cap of red and black smoke, 
formed liy the un1)urnt gases. 
It is only in the reducing atmosphere that the fine flamme 
reds are produced. Tlieir development is made easier by the 
arrangement of saggers. Itistead of being entirely cemented 
with lute, openings from ': of an inch to i inch are left in the 
wads of lute which hold the saggers together, so that the flame 
will penetrate the latter and deposit carburets on the cupric 
glaze (Fig. 81). Tt is not necessary to saturate the kiln with 
smoke to obtain fine reds. A light cloud of smoke maintained 
up to the fall of cone 06 will do . The name of flammes has been 
given to these pieces because, contrary to other pieces, they are 
subject to the flame during the firing. Reducing firings are 
from 3 to 4 hours shorter than oxidising, but neither requires 
the cleaning of live coal out of the fire mouth, the latter being 
necessary only in neutral firing. When the coal has accumu- 
lated in the fire mouth, while reducing, it is left to burn out, the 
feeding of fuel being diminished until then. 
Ccs Se-rces sont Incowfl^t?"'^"^ 
Iixteas. Pes ii+eKvallei iOviK 
By faithfully following these instructions, every detail of 
' which has its inrportance, ceramists will be able to obtain 
from the fire the finest crimson reds as well as the most de- 
lightfully frosty crj'stalline glazes. 
Those who have a baking chamber in their kiln will not 
need to give special attention to the baking which will be done 
while firing. But those who, like myself, have no baking 
chamber, will proceed as is done for an ordinary firing, with- 
out however cementing the saggers with lute. If they want 
a light baking, they will stop when cone 013 is beginning to 
curb; if they need a strong hardening, thej^ will stop when 
cone 013 has completely fallen. 
As a conclusion I will call the attention of firers to the 
following primordial points: to obtain a reducing atniosphere, 
the fuel must be accumulated in the fire mouth, and the exit 
of the flame must be checked as much as possible. Inversely, 
for an oxidising atmosphere, just enough fuel nmst be fed to the 
fire mouth to allow the progressive increase of the heat and the 
flame must have perfect freedom of exit. 
It is necessary also to adopt a rational feeding of the fuel, 
and when one of the fire mouths is choked, not to take the coal 
out, but to even it up, or temporarily diminish the feed, which 
will give the fire mouth time to absorb its excess of live coal. 
XI— DRAWING THE KILN 
THE drawing of the kiln is the time of great excitement 
for ceramists. The fever which has taken hold of them 
during the preparation of art pieces grows with the progress of 
the work to reach its climax during the drawing which is the 
best lesson for future work as well as a succession of childish 
joys and disappointments. When the firing is finished the kiln 
is left to cool off duj-ing four days. The fourth day the stoppers 
of the three spyholes are withdrawn, also the stopper A for 
circulation of air. (Fig. 50, p. 228, Feb. T904). The covers of 
the fire mouths are loosened and lifted; the chimney damper 
alone is kept closed to avoid a draft whicli might affect the 
pieces. The fifth day the doors are loosened and the sand 
between them gathered. This sand will be screened for 
future use. 
V 
1 generally take the pieces out of the kiln eight days after 
firing. As each piece is taken out, the placing material is put 
in order. Broken saggers are temporarily tied with twine 
(Fig. 69), so that their pieces will not be lost and a few days 
later this material is thoroughly overhauled. It is cleaned 
with an instrument called a dressing iron (Fig. 92), the three 
sharper angles and the angular end of which allow one to 
remove the vitrified scoriae which may adhere to the saggers. 
Mo.st of the pieces of placing material are broken during the 
firing, but a large part can be used again, as for instance when 
in saggers, the cracks extend only from the heel to the center, 
and when, in rings, the cracks are distant from each other. 
Bats broken in two can be used again, but when broken in 
three, they should be thrown away. 
Whatever care has been taken of the casting of bats, many 
get out of shape and they should be made true so that the 
porcelains will alwaj^s rest on a flat surface. The grinding of a 
bat is the operation which has for object to remove all inequali- 
ties and hollows. To do this, two bats are rubbed against each 
other, while the two faces in contact are from time to time 
sprinkled with gres sand. 
Although the white glaze remains where it has been placed, 
colored glazes which are more fusible, are apt to constantly 
overflow. To overcome this defect, small cohimns are used 
for supports, as I have explained in the article on placing. 
After firing, these columns are stuck to the piece, the glaze 
ha-sdng flowed over, and they must be detached. If they have 
been strongly washed with the infusible wash, a sharp blow 
with a wooden hammer will be sufficient to detach them, and 
nothing remains to do but to wear and polish the foot of the 
piece by rubbing it on a steel disc sprinkled with wet grhs 
powder; or it wifl be easy to find a wheel to do this work, the 
faience makers using the same instrument.* As I have no 
*Carborunduin wlieels made specially for pottery work are sold in this 
country. Care sliould be taken to buy the proper size of the carborundum 
grain. — (Ed.) 
