The student should experiment with the different dyes and classes of dyes before attempting a serious piece of work; but in general, all the Salt colors and the Acid colors will discharge readily with this paste, and remain colorless. The Vat colors and the Sulphur colors can also be reduced to colorless compounds, but it is not always easy to wash them out of the cloth after the reduction, and, if they remain in it, they are apt to regain their color, on standing in the air. The dyed cloth, carefully washed and pressed and dampened, is stencilled with the above paste and allowed to dry. When dry it is steamed, as described in the last chapter, and it will be noticed that when a certain temperature is reached the color will be discharged. As soon as possible afterwards the cloth is to be washed in a hot soap bath to remove the reduced color compound (which, as a rule, has little affinity for the cloth) and to get rid of the paste. Then the cloth is dried and finished. When trying this process with the Vat dyes it is best to soak the cloth directly after steaming, and before soaping, in a warm bath containing a little free caustic soda (remember this is apt to burn the fingers) because the reduced colors of this class are not, as a rule, soluble in water, and are apt to oxidize again in a soap bath. _Results._—In following up these various experiments in our laboratory we have not used this process in much as the Resist stencilling, but there is no reason why it should not give just as good results. Indeed, the craftsman will probably find, after a little practice, that it is easier to get clear white patterns with this than with the other. It has the disadvantage of requiring the rather bothersome steaming process, which reduces its value for many purposes. Still it will often be found that simply ironing the dried stencilled cloth with a hot flatiron, with a damp cloth between, will cause the reduction to take place quite satisfactorily. The chief advantage of this process over the other is that, as the dyeing is done before and not after the stencilling, it is possible to get the exact shade of background required. While, in the resist stencilling every minute, almost indeed every second that the stencilled goods are left in the dye-bath, is liable to obscure the pattern. And it is hard to get first-class results, as regards fastness to rubbing and washing, and it is impossible to match shades, when working so hurriedly. Then, too, this discharge process permits the use of almost every color on the list, while the resist process practically confines the craftsman to the use of the Sulphur dyes only.