The Basic Stencil Paste is prepared by mixing with the paste a solution containing the Basic color, dissolved in acetic acid, and also containing a considerable quantity of tannic acid. As long as there is free acetic acid present in this mixture the color remains in solution, but directly the acid is driven off, an insoluble compound remains, formed by the combination of the tannic acid with the color base. This happens on steaming, and the insolubility of the product is still further increased by passing it through a weak bath or wetting it with a weak solution (half a teaspoonful to the quart) of tartar emetic. Accordingly, to use this stencil paste on silk or, indeed, on cotton, the slightly dampened goods are stencilled with the paste, thinned if desired with water and a little acetic acid. Then directly they are dry enough so as not to run they are well steamed, then the gum rinsed off with a little warm water, and the goods moistened with the tartar emetic. After this they can be washed with soap with little or no danger of running. =(c) Wool.=—Wool is rarely stencilled, although stencil patterns can be produced very well on it by using acid colors with a little oxalate of ammonia (about the same amount as the dyestuff), dissolved in a drop or two of water, and thickened with a little gum tragacanth. When this paste is applied with a brush, and then dried, the result is not fast at all, merely a distinct stain; but if steamed at once the oxalate of ammonia decomposes, leaving oxalic acid, which, combining with the color and melting down with it in the fibres, makes the dyestuff adhere quite firmly. =(d) Cotton and Linen.=—It is much more difficult to stencil satisfactorily on vegetable goods, such as cotton and linen, than on the animal fibres above mentioned, because they are expected to stand very much more severe treatment. The fastness to washing needed for a handsome silk scarf is far less than for a cotton shirtwaist, or linen table-cover, and unless the results on the latter are at least as fast as the average calico print, the result is considered a failure. There are three classes of dyes which can be used in this connection, the Basic dyes, the Sulphur dyes, and the Indigo or Vat dyes. The Basic stencil pastes have just been described, in connection with silk stencilling, and when carefully used they will give very fair results on cotton, and even on linen, provided it is free from dressing, and is not too coarse and thick. It is hardly worth while trying to fasten Basic dyes, by hand stencilling, upon such materials as heavy, coarse Russian crash, for instance, such as friends and students have frequently brought in to experiment with. But for light, thin materials, and especially for mercerized goods, poplins and the like, it is possible, with a little practice, to get effects that are fast to ordinary washing.