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7. From what animal is mohair obtained?
8. Of what does the silk fiber consist?
9. What are the animal fibers?
10. Why are they called animal fibers?
11. Of what fibers is cotton cloth composed?
12. From what plant are cotton fibers obtained?
13. From what plant is the linen fiber obtained?
14. What are the most important vegetable fibers?
15. Name four other vegetable fibers.
16. Why are these fibers called vegetable fibers?
=Experiment 8--Wool Fiber=
Apparatus: Pick gla.s.s, microscope, 2 pine cones, foot-rule.
Materials: Raw wool, woolen yarn.
Reference: _Textiles_, chapter i.
_Directions_
1. Separate a strand of woolen yarn into fibers. Examine both these fibers and fibers pulled from the raw wool. Would you describe these fibers as coa.r.s.e or fine?
2. How do the fibers feel to touch?
3. Test the strength of the wool fibers by trying to break them.
4. Measure the length of several fibers.
5. Why was it difficult to straighten the fibers to measure them?
6. Extend the fiber to its full length, then release. How does this prove the fiber to be elastic?
7. Examine the fibers under the microscope. Describe. Notice that the wool fiber is cylindrical in shape. Notice that it is covered with scales which overlap much as do the tiles of a roof or the spines of a pine cone.
8. Hold one pine cone with the spines pointing upward. With the spines of the other pointing downward press the second cone down on the first. What happens? Just so the scales or points of the wool fibers hook into one another and interlock. These scales or serrations give to the wool fiber its chief characteristic which is the power of interlocking known as _felting_ or _shrinking_.
9. See _Textiles_, page 2, the drawing of a magnified wool fiber. Make a drawing of a wool fiber.
10. Examine under the microscope a hair from your head. Wool is only a variety of hair. Notice that the scales on the hair lie close to the stem and do not project as in the woolen fiber, hence hair fibers cannot interlock as wool fibers do. The scales lying close to the hair give a smooth surface to the fiber and make l.u.s.ter a characteristic.
11. Compare the wool fiber with hair, noting two differences.
_Questions_
1. With what is the wool fiber covered?
2. Of what advantage are these scales or points?
3. What is the chief characteristic of wool?
4. What is meant by the shrinking or felting power?
5. Name five characteristics of the wool fiber.
=Experiment 9--Mohair Fiber=
Apparatus: Microscope, foot-rule.
Materials: Wool fibers, mohair fibers, sample of mohair brilliantine.
References: _Textiles_, pages 1, 37, 97.
_Directions_
1. Pull a mohair fiber from the fleece. Hold it up to the light.
Describe the fiber as you see it.
2. Hold a mohair fiber and a wool fiber side by side to the light.
Note the differences.
3. Measure several mohair fibers.
4. Examine the mohair fiber under the microscope. The fiber is covered with scales, but they lie close to the fiber and do not project in points as do the scales on the wool fiber, hence mohair will not felt to any degree.
5. The Angora goat of Asia Minor furnishes the mohair. This goat is being raised in the western states of the United States now.
6. Detach from the sample of mohair brilliantine a warp thread; a filling thread. Which is mohair? Which is cotton?
7. What word would describe the feel of mohair brilliantine? the appearance?
8. What are the characteristics of the mohair fiber?
9. What are the uses of mohair? Mohair is used in the manufacture of plushes, dress fabrics, and imitation furs.
_Questions_
1. Why will mohair not felt as wool does?
