RERAMIC STUDIO 
203 
the action of the chromogens or coloring agents used. The 
glaze given above is quite suitable for making a certain class 
of greens but will not work for every color. Another glaze for 
the same heat but different color effect is as follows: 
White lead 50 
Feldspar 32 
Barium carbonate 12 
Kaolin 5 
Flint I 
The Barium carbonate used should be the " precipitated " form. 
There is a natural mineral named " Witherite " which is -very 
pure but is hard to grind sufficiently fine for glaze work. 
With these two glazes considerable work can be done, in 
fact, at the temperature given no other white glaze will be 
necessary and the coloring agents can be added to either glaze 
according to the effect desired. The white glaze should, how- 
ever, be tried and proved before taking time and trouble with 
colors. 
This remark will, probably, call forth some exclamation of 
surprise for it will naturally be expected that in these papers 
only those mixtures which have already been tried and proved 
will be advocated. Let it be understood therefore that these 
mixtures in the kilns and under the treatment given at Alfred 
have been found perfectly satisfactorj^, but this is by no means 
equivalent to saying that they will be equally satisfactory else- 
where. No two manipulators work in just the same manner, 
no two kilns fire jtist alike and for these reasons it is not possible 
to put forth an infallible recipe. All that can be said is " I have 
done good work with this." Let no one%e discouraged, there- 
fore, if immediate results are not obtained. The art of the 
potter is the most troublesome as well as the most fascinating 
of all the arts and for that reason, perhaps, the best worth 
mastering. 
If a given mixture does not behave just as it is expected 
to, the door is open for a few experiments. One or another of 
the materials may be increased or decreased in the mixture, 
taking care to make accurate notes and to observe closely. 
The fire may be changed, made longer, or shorter, more air 
to the fuel or a less abundant supply of fuel. There are many 
ways in which a patient and intelligent worker can influence 
the results. 
Then having secured a white glaze which will meet all 
requirements a goodlj^ batch of the same should be mixed and 
ground. Not more than can be manipulated at one time 
should be weighed, but two or three such weighings can be pre- 
pared and then mixed together. When dried and carefully 
put away in jars, this stock (without mucilage) will keep for 
ever and can be drawn upon as needed. 
In most cases the color can be added to those glazes, l)utin 
a few instances it is best to grind glaze and color together. 
For a simple green add to glaze No. I three parts black 
oxide of copper. The method of adding this colorant is im- 
portant and this is how it is done : 
A glass slab and muUer are almost indispensable here. 
The small one used for grinding colors will serve at a pinch but 
is usually two small for glaze work. If possible a sheet of 
plate glass about 20 or 22 inches square should be procured 
and this should be set in a wooden frame which lies flush with 
the glass, that is there is no raised edge. A muUer weighing 
some two pounds or more is about the right size and with a 
little practice good worli can be done with it. To make the 
DESIGN TO BE EXECUTED IN BLUE OR GREEN— KATHERINE SINCLAIR 
