133. Royal Blue

133.    Royal Blue. This is dyed in the same manner as Napoleon Blue, but the liquors are stronger - using 2 pints iron solution, 2 gills hydrochloric acid, and 4 ounces tin crystals. The Prussiate tub is made up by dissolving in it 1 pound ferrocyanide of potassium, and adding 1 wine-glassful of sulphuric acid, and 1 of hydrochloric acid. If not dark enough with putting through once, repeat.

134. Blue

134.    Blue. Copperas (sulphate of iron) is used as a mordant for dyeing blue by ferrocyanide of potassium (prussiate of potassium ). The copperas best suited for the blue vat should be of a dark rusty green color, and free from copper, zinc, or alumina. Thus, 10 pounds cotton may be dyed a good rich blue by working it for 15 minutes in a solution of 4 pounds copperas; wring out; and then work through a solution of 4 ounces of the ferrocyanide; finally, wash in cold water containing 1 ounce alum in solution.

Copperas is also used as a dye by the oxidation of the iron within the fibre. Thus:

135. Iron Buff or Nankeen

135.    Iron Buff or Nankeen. Take 2 pounds copperas, and dissolve in warm water, then add the requisite quantity of water for working the goods; work in this for 20 minutes; wring out, and put immediately into another vessel filled with lime-water, and work in this for 15 minutes; wring out and expose to the air for half an hour, when the goods will assume a buff color. If the color is not sufficiently deep, the operation may be repeated, working through the same copperas solution, but using fresh lime-water each time. The goods should be finally washed through clean warm water and dried.

136. Nankeen or Buff Dye for Cotton Goods

136.    Nankeen or Buff Dye for Cotton Goods. To a tub of hot water add 1 pint nitrate of iron, and work in this for half an hour 10 pounds cotton previously bleached (see No. 125 (To Bleach Cotton Cloth)); wash out in water, and dry. This process is simple and easy, and produces a permanent dye.

137. General Receipts for Dyeing Cotton

137.    General Receipts for Dyeing Cotton. In the following receipts, the quantities are given for 10 pounds cotton, whether yarn or cloth. For more or less cotton, the quantities can be increased or diminished in proportion; but when small articles are to be dyed - such as ribbons, gloves, etc..—a little more of the materials may be used in proportion to advantage. "Where washing is referred to, it is always in cold water, unless otherwise specified.

138. Common Black

138.    Common Black. Steep the goods in a decoction of 3 pounds sumach while it is hot, and let them lie over night; wring out and work them for 10 minutes through lime-water, then work for half an hour in a solution of 2 pounds copperas. They may either be washed from this, or worked again through lime-water for 10 minutes; then work them for half an hour in a warm decoction of 3 pounds logwood, adding 1/2 pint chamber lye; before entering the goods, lift and raise with

2 ounces copperas in solution; work 10 minutes, then wash and dry.