Rutile has not before been mentioned. It is a crude oxide of titanium and is exceedingly useful in high temperature work for producing odd, mossy and crystalline effects.
These mixtures make no pretense to be complete, they are given as suggestions only because if the artist-potter is to be successful he must be prepared to compound glazes which are the expression of his own individuality.
For burning high-temperature wares the kilns already described may be used but upon purchasing it should be stipulated that the kiln is to stand burning up to cone 11 or 12. Successful porcelain can be made at cone 10 but better results are secured at cone 12, though, of course, the wear upon the kiln is proportionately greater. Stoneware requires a burn of about cone 9, higher or lower according to the clay used but fine results must not be expected below cone 7 nor is it necessary to go higher than cone 10.
CHAPTER XIX
Clay-working for Children
One of the modern developments of clay-working is the use of it in elementary and high schools as a branch of manual training. In this, clay meets the most exacting needs of the work for it affords a perfect means of self-expression. Other arts interpose between the pupil and his material a series of tools or appliances, more or less elaborate, which constitute a barrier to the personal touch. Clay presents no such obstacles. The ten fingers are all the tools that are necessary at the beginning and, consequently, the personal equation in clay-working is remarkably high.
In the kindergarten the children take to clay work as little ducks to water and the interest is never lost. In this way, clay, instead of adding to the labors of a teacher already overburdened by a plethora of subjects, constitutes a real relief. The work is so interesting that it moves along of itself and all that is needed is intelligent direction.
It is, of course, necessary that anyone attempting to teach clay-working to children should have a knowledge of methods and principles. The essence of power, especially in teaching, is reserve, but there is great danger in expecting too much from small heads and hands. In the early exercises the skill of the teacher should even be employed to conceal her art. It is a mistake to place before elementary pupils work which is far beyond their reach. Let the teacher make before the class something which they themselves can do if they try and they will be encouraged to greater effort.
A small cylinder is a suitable beginning exercise for several reasons. The form is definite and the result may therefore be easily criticized by the children themselves, the size of the piece may be readily adapted to the small fingers and the simplicity of line enables the attention to be concentrated upon the manipulation of the clay.