KERAMIC STUDIO 
147 
which is not very complex (fig. 16) and consists of a tank A and 
a lead pipe B. The tank is in zinc, of cylindrical shape and 
with vertical axis. It is 27 x 12 inches. It is placed about 
5 feet aboA^e ground, solidly fixed to the wall or resting on a 
table. The cylindrical shape makes easier the stirring of the 
liquid with a spatula in shape of an oar (fig. 1 8), which is moved 
from left to right. The bottom of the tank is in funnel shape 
(C) to make possible the thorough emptjdng of the slip, and it 
ends with a brass union (D), which connects it with the pipe. 
This pipe, which is 52 inches long by f inch inside, is curved in 
its lower part and supplied with three copper faucets. The top 
one (H) enables the slip to flow into the pipe, the one at the 
other end (E) allows it to enter the mould, while the faucet in 
(F) is used to empty the apparatus. 
The lower part of the pipe passes through a table (T) and 
the opening is on a level with the surface of this table. It is 
there that the mould (M), thoroughly dried out, is placed. On 
the table rests a circular plaque in zinc (Z) 20 inches in di- 
ameter, to facilitate cleaning (fig. 17). 
In order to avoid the leaking of slip through the inter- 
stices between the mould and the table, a circular plaque of 
virgin beeswax (V) i-inch thick, is kept around the opening 
(fig. 17), and is glued with wax softened by the heat of the 
hand. Even then it may happen that streams of slip will 
escape, and to make the closing of the mould absolutely tight, 
a long and narrow wad of fresh slip (R) is rolled and placed on 
the wax all around the opening of the pipe. The mould being 
placed on this wad flattens it and makes the closing perfectly 
tight. 
Before placing the mould over the apparatus, it is abso- 
lutely necessary to ascertain that all its parts join well, and 
especially that they are very tightly tied with one or several 
ropes with solid knots. If these ropes were in the least loose, 
the pieces of the mould would come apart under the pressure 
of the liquid and the vase would be ruined. 
The weU tied mould is put in place. The slip which has 
been passed through the screen No. 120 is poured in the tank, 
and is left there to rest a little while. To be sure that aU the 
air bubbles, these great enemies of casting, have beeri expelled, 
the outside wall of the tank should be sharply knocked several 
times with a stick of hard wood, such as oak. The air bubbles 
which may remain in the liquid then raise to the surface and 
burst. When one is sure that everything is in perfect order 
and in place, the casting proper is done. 
The two faucets E and F remain closed. The faucet H is 
opened. The slip flows in the pipe and expels the air from it. 
It is necessary that not ^ne bubble should remain in the pipe. 
Then the faucet E is opened wide. At once the liquid fiUs the 
mould. • When it is just about to be entirely filled, the faucet 
H is almost closed, so that it will let in just the quantity of slip 
necessary to replace that which is absorbed by the mould. 
When the thickness of the coagulated paste is judged to be 
sufficient, and it is easy to follow the progress of the thickening 
on the false rim, provided there has been no overflow, the faucet 
H is entirely closed, and the two faucets E and F opened. The 
p3 '^ 
excess of slip flows into the pail X and both the mould and the 
pipe are emptied. The mould should be left to rest a good 
quarter of an hour, then with great care it is detached from the 
wax disc by lifting it, and it is carried without jerks on a table 
where it will stay until next day. 
If the mould is heavy, it should be lifted with a tackle 
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