This iron buff is used to this day, though of course it has lost the importance it had in the past. The red sails of the fishermen in the Mediterranean show this color; and it is a useful and interesting dye for weavers of hand-made rugs, curtains, and the like, because of its pleasing tone and great permanence. On the other hand, it is very likely to rub; and it fills the fibre of the cloth with mineral matter, thereby making the material stiff and hard to sew or cut. _Preparation._—Our colonial ancestors made this color cheaply enough. They carefully saved all the scraps of iron and steel that they could find—old horseshoes, broken knife blades, etc., etc.—and placed them in a barrel half filled with vinegar and water. Little by little the iron dissolved in the acid and, when it was strong enough, the housewife would soak her homespun cloth, or other material, in the solution, warming and stirring it, and making it absorb as much of the liquor as possible. Then she would take it out, wring it thoroughly, rinse it slightly, and dip it for a minute or two in another barrel half filled with a water extract of wood ashes. [Illustration: PLATE II. JAPANESE TOWELLING, SHOWING IMPRESSION OF FRESH DAMP LEAVES] After removing from the solution and wringing again, the goods were shaken out and exposed to the air for some minutes, during which time the color would develop—in other words, would make its final change to yellow or orange, or even to brownish-red, according to the amount of iron absorbed by the fibre. The process, nowadays, is much the same, excepting that, for the first or iron bath, it is cheaper and easier to use a solution of the green crystalline iron salt, known as copperas, or as _ferrous_ (iron) _sulphate_. This can be obtained at, or through, any drug store at a very low price, as it is not necessary to buy a chemically pure product. The ordinary commercial salt is as pure as the work requires; this dissolves quite readily in warm water. The amount of copperas to be used, to dye a particular lot of material a particular shade, can only be determined by experience and experiment. It is always easy to build up a color, i.e., to deepen its shade if it is too light, by dipping the fabric over again in the same dye-bath. Indeed there is a general rule to be observed in dyeing all colors like this iron buff or the manganese brown—as well as the sulphur and indigo colors, which will be described later—that are developed, or fixed, by exposure to the air. Whenever dark shades of these colors are desired, they should be produced by successive dippings in weak baths, rather than by one or two dippings in strong baths. This avoids rubbing, as far as possible, and lessens the injury to the cloth fibre. In general, it is best to start with a dye-bath containing some three or four tablespoonfuls of copperas to one gallon of hot water.