They are applied in a boiling bath containing a little acetic acid, and a good deal of salt, especially for full shades. For lighter shades, the presence of salt is hardly necessary. The goods are to be finished just as with the Acid dyes, with a soap bath followed, if the scroop is desired, by a weak bath of acetic acid. The results, when carefully done, are very good. They possess, however, one disadvantage for the amateur dyer. These colors are quite hard to strip, and so, the desired effect must be produced the first time, or not at all. It is not possible to strip an unsatisfactory shade in a hot soap bath, and dye it over and over again without injury, as in the case with Acid dyes. They are best stripped by soaking in a bath of sodium hydrosulphite, and then washing. _Embroidery Fast Colors._—While the above process gives shades fast enough against all ordinary washing, it sometimes happens that silk must be dyed fast enough to withstand exactly the same treatment that coarse cotton or linen goods are subjected to, without bleeding or staining. The salt dyes are not quite fast enough for this, particularly because, not having been converted in the dyeing process into a special insoluble condition, if they should be detached from the fibre by strong or hot soaping, they would be liable to stain the neighboring tissues and not wash off quite clear. One of the hardest tests that colored silk is called upon to stand is when, in small quantities, it is used with a large amount of white linen or cotton goods. Thus, for instance, when monograms are embroidered in red or blue silk upon white towels or napkins, and the latter are scrubbed, week after week, in the regular wash, the color must be fast, indeed, not to show some evidences of running. Hence the term “embroidery fastness” as applied to this class of dyes. Thanks, also, to the amiable practice of the modern laundress of lightening her labors by the addition of bleaching powder and other strong chemicals to the washtub, it is very important that a silk dyed “embroidery fast” should be able to withstand the action of these agents as well as of soap. Up to the last few years these colors were only obtained by the use of the Alizarine dyestuffs, the full rich scarlet so often used for this purpose being the modern form of the old, madder-dyed, Turkey red of our forefathers.