KERAMIC STUDIO 
Both the sands of Decise and Fontaincblcau may be bought 
from Loulenc Freres, rue Vieille du Temple, 92, Paris- 
This mixture "is handled in the same way as the first, and 
both have the disadvantage, when they are fired in an oxidising 
fire to be, after firing, of a j^ellowish tone, which gives them the 
appearance of faience or pipe clay. They acquire their beauti- 
ful grej' blue tone only in a reducing fire. 
As I fire alternately with oxidising or reducing fires, ac- 
cording to the effects I wish to obtain, and as I do not generally 
execute pieces of large sizes, I have adopted a third natural gr^s 
clay called Kaolinic sand of Lange-RoUin (Nievre), owner, 
Mr. H. Carizot, 17 ixie dcs Perrieres, Nevers. 
It is highh^ important that this sand be verj^ finely gi-ound. 
It is verj' rich in alkali, which, in the shape of white muscovite 
mica, reaches nearh' 6%. It is a complete product, which does 
not need any preparation or the addition of any other element. 
It keeps its fine ash grey tone in both fires. Its paste, of verj^ 
fine grain, is silicious and resembles closely some Chinese porce- 
lains. I have obtained with tliis gres very beautiful flamme 
reds of copper. It receives without creasing the glaze of the 
hard Limoges porcelain. Its shrinkage is somewhat greater 
than that of the Sevres gres or the Limoges porcelain, and these 
shrinkages are deceiving, as it is difficult to get used to the fact 
that after firing a model may be reduced one fourth. 
In the Salon of 1902 I exhibited the first fine pieces made 
from that gres, and gave them to the Museum of Nevers. 
The black clay of St. Amand en Luysaie, which is the basis 
of the vSevres gi'es, is a natural gres clay, which may be used bj' 
itself, without the addition of any other element. It is ver5^ 
fine and plastic. With this gres Bigot makes vases 3.^ feet 
high, bath tubs 5 feet 7 inches long, 33 inches wide and 24 inches 
deep. It is the material which Carries used for his ceramics, 
and which is used bj^ his imitators, ceramists " a Teau de rose " 
who have their wares fired in the kilns of the countrj', and who 
are legion. 
Here then ai'e four gres pastes, which all are easy, 
because their pi'eparation can be made in small quantities, say 
40 lbs., which does not require a costly outlay. 
If in iriost cases the composition of gres is simple, it is not 
so with porcelain. The various porcelain bodies used in Europe 
are made of difterent elements. No natural porcelain paste 
exists. 
I will not midertake here to make comparisons, or to give 
and scientifically formulate the composition of the various 
European and Chinese porcelains. I will onty state that the ex- 
treme compositions of practically" possible porcelains will be 
found between the following limits: 
65 to 35 kaoHn 
20 to 40 feldspar 
15 to 25 silica or quartz. 
Kaolin is the plastic element, felspar and silica are the 
fusible elements. The extreme combinations nmst receive, 
one a temperature of 1500° C (about cone 18), the other of 
1350° C(cone 11), in order to vitrify, and from this fact the pro- 
ducts are bound to have different properties. 
The first extreme combination, very rich in kaolin and 
consecjuently in alumina, will resist well variations of tempera- 
ture, will accept the hard felspathic glazes, on which the steel 
of the knife will have no effect, excellent qualities for table 
ware, but it will not keep a wide range of colors. The hard 
Sevres porcelain invented bj^ Brougniart and the Dresden por- 
celain are in this class. 
The other extreme combination, with more silica and less 
alumina, fires at a lower temperature, which makes it possible to 
introduce as much as l6% lime in the glaze, so as to soften it 
and to obtain more varied and brilliant colorations. To this 
tjj^pe belong porcelains from China, Japan, Russia, Bohemia, 
Limoges, that of Chaplet and mine. 
Between these extreme fabrications all intermedial com- 
binations can be used. 
At the beginning I adopted the Limoges porcelain which is 
about half way between the two extremes. The paste, care- 
fully prepared, was bought from Mess. Lacroix et Ruaud, 
manufacturers of porcelain pastes, Limoges (Hatite Vienne). 
They make four different qualities. I used to buy and buy yet 
for certain pieces the first of these four qualities, called FF 
(paste for figures and flowers.) It costs 18 francs (S3. 60) per 
TOO kilos. It is passed through the screen No. 120. Its formu- 
la is: 
Pure kaolin, 37. 27 
Quartz, 27, 35 
Felspathic debris, 35, 36. 
The glaze which fits this paste is of the hard type, that is, 
exclusively felspathic. It is .sold for 12 fr. per lOO kilos. After 
firing the porcelain is of a pure white and beautiful translu- 
cencj'. Its palette is rich. 
Porcelains worth^'^ of attention must have many (lualities. 
The paste must be translucent, hard, impossible to scratch 
with .steel, homogeneous, very sonorous, completely vitrified, 
and when broken, nmst show a sharp angular break with a very 
fine and bi'illiant grain. In this condition it will be impervious 
to water and proof against injuries by frost, and will resist 
climates like ours in which humidity is a great disintegrat- 
ing agent. These characteristics, especialty translucency and 
vitrification, constitute the definition of porcelain. If one of 
thenr is missing, we have another 1-dnd of ware. If the paste 
keeps all properties except translucency, we have a gres; if it is 
not vitrified, we have terra cotta, faience or pipe clay. 
Porcelain paste should be diluted in a zinc vessel, in the 
fabrication of which iron has been strictly avoided. Iron is the 
great enemy of porcelain, as particles of oxide of iron (rust) will 
make on the brilliant white, black spots which cannot l)e re- 
moved, a serious flaw, if it occurs on the decoration or on 
figures. After the paste has been in water two clays, it is 
poured, as is done for gres, in a plaster basin, and when the 
water is absorbed, one has a soft paste readj^ for modelHng. 
During these operations one must be very careful to avoid the 
introduction of dirt in any form. 
As a rule porcelain makers do not manufacture their paste 
themselves, as it reqiures a special and costly outfit. Only the 
great manufacturers, owners of quarries, have their mills to 
grind the materials. Sevres does not own kaolinic quarries l)ut 
buys the best of the Limoges kaolins. 
With the paste FF I made all my first ceramics. I used 
it from 1879 to 1895 and have very seldom had failures from 
any fact in relation to this paste and its glaze. But, after the 
creation at Sevres, of the new hard porcelain, called PN (por- 
celain nouvelle),! found from numerous experiments, that it had 
among other advantages, that of firing at a lower temperature, 
about 100°, of allowing a more rapid work in the execution of 
pate sur pate decoration, without any flaws resulting from this 
rapid work, and also the great advantage, so long studied at 
Sevres and at a great cost, of making possible the combination 
of gres with this porcelain and its glaze. I did not hesitate to 
adopt it, and was going to begin its fabrication, when an en- 
gineer, Mr. Frugier, a pupil of the laboratory of Sevres, fixed 
his residence at Limoges, 17 rue du Chinchanvaud, in order to 
manufacture the new paste, which he sells: 
Porcelain paste, PN., dried and sifted, 15 fr. ($3.00) per 
TOO kilos. 
