_Stripping or Degumming._—This thrown silk must then be prepared for the dyeing by getting rid of the gum, which not only makes the silk stiff and destroys its lustre, but which also would interfere with the smooth, even dyeing of the fibres themselves. For this purpose the silk, in skeins, is thoroughly washed, or “stripped,” by soaking in two or three successive baths of hot, strong, neutral soap solutions. In the dyehouses Castile (olive oil) soap is invariably used for this purpose, and, while made of cheap grades of olive oil, it is always, in good dyehouses, of excellent quality, for the presence of even minute amounts of free alkali in these baths is liable to greatly injure and “tender” the silk. _Boiled-off Liquor._—The soap solution from these stripping baths is not thrown away in the dyehouses, but is carefully stored as a valuable reagent. Under the name of “boiled-off liquor” it is almost exclusively used, by the dyers, for color dyeing. It is not often used in black dyeing, and therefore, in a dyehouse, the presence of a large and well-patronized black department is considered of great importance as providing the color dyer with an abundant supply of boiled-off liquor. The stripped or degummed silk is now ready for weaving directly, the resulting white cloth being sometimes finished and sold as such, and sometimes “dyed in the piece.” In most cases, however, the stripped silk is weighted, dyed, and finished “in the skeins,” before weaving. =Piece Dyeing.=—In dyeing by the piece, the stripped silk is passed through a weak acid bath, usually acetic, and then woven into goods of the desired quality. These goods are then dyed in the piece by being run through the dye-bath until they are of the proper shade. The dye-bath (for colors) is made by stirring the proper quantity of Acid dyestuffs into a hot bath of boiled-off liquor (the bath in which the silk has been stripped), which is faintly acidified, or “broken,” as the technical phrase goes, by the addition of some sulphuric acid. This boiled-off liquor has the property of laying the dyes on the silk evenly and thoroughly, and is better for that purpose than any other medium. For amateur work, or where boiled-off liquor cannot be obtained, very fair results can be obtained with a strong bath of olive oil soap (Castile or Marseilles), “broken” with weak acid, generally dilute sulphuric acid. The term “breaking” the soap bath is very significant. The acid should be added drop by drop to the frothing soap bath until the bubbles disappear and a thin iridescent film of fatty acid rises to the top of the liquid.