=Dye-bath.=—The color must first be dissolved in water, care being taken not to leave any undissolved lumps or specks of color floating around in, or settled at the bottom of, the dye-bath. For this reason it is generally best, in all dyeing operations, first of all to make a decidedly strong solution of the color, by dissolving a considerable quantity of it (depending of course on the amount of goods to be dyed) in hot water, in a pitcher or saucepan. In the dyehouse this would be called a “stock solution,” and would always be made of a definite strength,—say five parts of color to one hundred of water—and kept well covered up. Sometimes in hot weather it would be treated with a little preservative like benzoate of soda, so that it could be used at any time it was needed. When this color solution is added to the dye-bath, it should always be carefully strained through a piece of cheesecloth or any other fine medium that will catch the specks and undissolved lumps. Otherwise spots are liable to appear, on the finished goods, which it is almost impossible to eradicate without stripping off every trace of color from the dyed material. _Water._—The dye-bath is prepared with plain water. The amount necessary for each lot of goods can only be told by experience. For some classes of dyes, like the Acid colors and the Basic colors, to be described later, the quantity of water makes but little difference. But for dark shades with these Salt colors it is best not to have more than enough water to thoroughly soak, and comfortably cover, the wetted goods, with enough room to stir and turn them easily. The dye-bath is now set on the stove to warm up and, when dyeing light or medium shades, some soap is usually dissolved in it. This is not absolutely necessary but helps to make the color go on more evenly, and penetrate the fibres better. _Soap._—For dyeing purposes in general, any pure, carefully made soap acts satisfactorily. For silk dyeing, and especially for silk finishing, it is said that greater lustre can be gained with olive oil (Castile) soap. But when this cannot be obtained, Ivory soap or Pears’ soap or, in fact, any good brand of bath or toilet soap will do almost as well. For the washing and finishing of wool and silk the use of strong laundry soaps should be avoided if possible, because they usually contain alkali, in the form of borax or of carbonate of soda, which is liable to “tender the goods.” For cotton and linen dyeing and finishing, this does not make any difference. The easiest way to add the soap to the dye-bath is to use it in one of the wire soap-shakers, which has a convenient handle, and holds half a cake or even a whole cake of soap at one time.