The clay can be procured from the pottery in broken pieces, or, better, in a semi-pulverized state from the trimming in making the wares. When in this state it is easy at any time to dissolve enough for use. It is, perhaps, better to prepare it just before it is to be used, as the longer clay stands, after it has been mixed with water, the more compact it becomes. When it has just been dissolved, it still retains air among its particles, and this renders the mixture more porous and less liable to crack. It soon dissolves in water and can be stirred until smooth. It may be strained through a sponge, alternately allowing the sponge to absorb the diluted clay and then squeezing it. Probably the most convenient way is to rub the clay in a mortar until all the lumps are dissolved. If a very small quantity only is needed it may be rubbed down upon the palette with the palette knife as it is wanted. A palette or a slab of glass may be used for mixing the colors and clay. The latter is the best, as it can be procured of large size, and as in this kind of work a considerable quantity of paint is necessary, there should be ample room to mix the colors. A slab of French plate glass, at least twenty by twenty-four inches, may be procured. This can be imbedded in plaster of paris, which will make it stronger, as well as furnish a white surface upon which the colors will show to better advantage. The powdered colors as procured are not perfectly pulverized, and must be well rubbed down with a muller and palette knife. It is even more necessary in this than in other kinds of painting upon pottery that the color should be well ground. If not rubbed down sufficiently _before being mixed with the clay_, particles of color which are scarcely apparent before firing, will show when the work is glazed, forming specks in what should be, a perfectly uniform tint. If the color is mixed with the clay before it has been perfectly dissolved, it will not afterward be possible by any rubbing down to remove the specks from the mixture. The colors, after being thoroughly ground, can be mixed with clay in such proportions as may be desired. The white clay takes the place of white, and is used to lighten every tint, as well as to form a body for the colors. It is a good plan, where experience has rendered it possible to do it with judgment and certainty of result, to mix the various tints in water with clay, in quantities, and then allow them to dry. When dry, they can be pulverized and the colored powder can be put away in bottles for future use. This saves time when painting, and also ensures a like result from the use of a mixture which has already been tested and found to be satisfactory. It is only, however, after considerable experience in mixing colors, and verifying their results, that this can be safely done.