ame experiment, placing the untwisted yarn in sulphuric
acid. Apply heat and note the effect.

What is the acid test for vegetable fiber?

What is the acid test for animal fiber?

Examine different fabrics to see whether they contain vegetable or
animal fibers.

=Experiment 45--Difference between Cotton and Linen Fabrics=

Examine a real linen towel and a cotton towel. Wet your hands and use
both towels to dry them. Notice which of the fabrics absorbs the
moisture quicker, or which towel dries the hands better.

Compare a cotton table-cloth and a linen table-cloth. Notice that the
linen fabric has a natural gloss, a cool, smooth feel, and launders
much better than cotton. The cotton fabric on the other hand gives off
a fuzz, and irons dull and shapeless.[29]

Linen is tough and strong, cool feeling, and has a long fiber. Linen
cannot be given a cotton fabric finish.[30]

Cotton on the other hand has a weak, short fiber, dull, warm, and
non-absorbent. After washing, cotton resembles a limp rag while linen
retains firmness and stiffness.

Which fabric absorbs the moisture more readily?

What is the difference in appearance between the two fabrics? Between
the fibers of the fabrics?

=Experiment 46--Test to Distinguish Artificial Silk from Silk=

Apparatus: Porcelain dish, potassium hydrate.
Material: Piece of silk fabric.
Reference: _Textiles_, page 240.

Since silk fabrics, particularly hosiery, are becoming popular,
various attempts have been made to produce substitutes for real silk.
To test a silk fabric, boil the sample in 4 per cent potassium hydrate
solution and note the effect. If it produces a yellow solution it is
artificial silk, if colorless it is pure silk.

Another simple way used by some workmen, although unhygienic, is to
unravel a few threads of the suspected fabric, place them in the
mouth, and masticate them vigorously. Artificial silk will soften
under the operation and break up into a mass of pulp. Natural silk
will retain its fibrous strength.

Test various samples of cheap "silk" hosiery.

=Experiment 47--Test to Distinguish Silk from Wool=

Apparatus: Porcelain dish, hydrochloric acid.
Material: Silk or woolen fabric.
Reference: _Textiles_, page 240.

Silk may be distinguished from wool by putting the suspected thread
or fabric into cold concentrated hydrochloric acid. If silk is present
it will dissolve, while wool merely swells.

Test variou