1. What is a solvent? an absorbent?
2. What is the best solvent to be used in removing stains from silks, coarse goods, and linens? from delicate silks?
3. Why is a brown ring often left after removing a stain?
4. How may grease and blood stain be removed from wash goods?
5. What is wheel grease? How may it be removed?
6. How will ammonia remove acid stains?
7. Does it remove all? Why not?
8. Explain the method of removing blood stain from cloth.
=Experiment 20--Dyeing Wool=
Apparatus: Large porcelain dish or casserole, filter.
Materials: Undyed piece of woolen and worsted fabric, undyed yarn, and undyed raw cloth.
Reference: _Textiles_, page 65.
_Directions_
1. Prepare a solution of coloring matter by dissolving a half ounce of diamond dye (green or red) in a quart of water. Filter the solution.
Place a piece of white woolen cloth in the liquid and boil ten minutes. Then wash the dyed fabric and notice whether the dyestuff washes off or not.
2. Repeat the experiment, using the same weight of undyed woolen yarn.
Repeat with worsted yarn.
3. Repeat the experiment using the same weight of wool sliver.
4. Notice which has the deeper color. The degree of color depends on the amount of twist in yarn. Which sample has absorbed the greatest amount of dyestuff from the liquid?
_a._ Why is a yarn-dyed fabric faster than a piece-dyed?
_b._ Why is a raw stock dyed fabric better than piece or yarn dyed?
=Experiment 21--Dyeing Cotton=
Apparatus: Porcelain dish, filter stand, etc.
Material: Piece of cotton cloth.
Reference: _Textiles_, page 67.
_Directions_
1. Prepare a solution of coloring matter by dissolving a half ounce of logwood in a quart of water. Filter the solution. Place a piece of cotton cloth in the liquid and boil ten minutes. Then wash the dyed fabric and notice whether the dyestuff washes off or not.
2. Repeat the same experiment and use a piece of cotton cloth that has been previously washed in common alum.[25] Note the effect. Which has the greater attraction for dyestuffs, cotton or wool? Why is alum used?
3. Repeat the same experiment, using first the same weight of cotton yarn and then the same weight of cotton sliver. Notice the results.
Which piece of cotton holds the dye best, that which was dipped in alum or the one that was simply boiled in the solution?
=Experiment 22--Weighting Silk.--Affinity of Metallic Salts for Silk=
Apparatus: Porcelain dishes.
Material: Silk yarn.
Reference: _Textiles_, pages 212-214.
_Directions_
1. Weigh separately two skeins of dry silk and distinguish skein No. 1 by looping some cotton thread into it. Prepare a tepid bath containing 10 gm. strong sumach extract in 400 cc. water. Enter the skeins of silk and work for 15 to 20 minutes, meanwhile slowly raising the temperature to about 150 F. Remove, squeeze, rinse with water, squeeze, and dry skein No. 1 for weighing.
2. Meanwhile prepare another bath containing 4 gm. of copperas (ferrous sulphate) in 400 cc. cold water. Work skein No. 2 in bath for 10 minutes cold. Remove, and rinse well; save the iron bath. Repeat the treatment in the sumach and iron baths several times more, finally wash the sumach iron skein in 1 per cent hot soap solution; rinse, squeeze, and dry. Weigh each dried and cooled skein and note the increase in weight of each. Save sample for Experiment 23 and note the effect of weighting on the yarn.
=Experiment 23--Dyeing Silk=
Apparatus: Porcelain dish, filter stand, etc.
Material: Piece of silk yarn.
Reference: _Textiles_, page 210.
_Directions_
1. Prepare a solution of coloring matter by dissolving a half ounce of logwood in a quart of water. Filter the solution. Place a piece of silk skein, from Experiment 22, in the liquid and boil ten minutes.
Then wash the dyed silk and notice whether the dyestuff washes off or not.
2. Repeat the same experiment using the same weight of silk yarn without weighing it. Compare the results.
=Experiment 24--Test to Distinguish Piece-Dyed from Yarn-Dyed Fabric=
Apparatus: Pen knife.
Materials: Woolen and cotton fabrics.
Reference: _Textiles_, pages 66-68.
_Directions_
Unravel threads of the suspected sample, and with a blade of pen knife note whether the dyestuff has penetrated through the yarn as noted by the depth of color in the interior of the yarn. In case there is the same depth of color in the interior as on the surface, the fabric is yarn-dyed. If on the other hand, the interior of the yarn is not so highly colored as the exterior, it is piece-dyed.