e most important vegetable fibers?

15. Name four other vegetable fibers.

16. Why are these fibers called vegetable fibers?

=Experiment 8--Wool Fiber=

Apparatus: Pick glass, 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 coarse 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 luster 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 ligh