en the fibres are
wet, they expand somewhat and the projecting
scales, or notches, are loosened. If the
material is rubbed at this time, the notched
edges interlock.

(2) The use of strong soaps or alkalies. These
act chemically on the fibres and soften and
expand them, causing the notched edges to
become so prominent that they catch in one
another.

NOTE.--The structure of woollen fibres may be
sketched on the black-board and compared with
those of cotton and linen.

To impress the foregoing principles, a few experiments will be found
most useful.

EXPERIMENTS WITH CLOTH MADE OF WOOL FIBRE

1. Boil a piece of new woollen cloth for five minutes. Dry, and compare
with an original piece.

2. Saturate a piece of new woollen cloth with a strong solution of
washing soda. Dry, and compare with an original piece.

3. Wash a piece of new woollen cloth in each of the following ways:

(1) By rubbing soap directly on the cloth and
then sousing the goods in the water.

(2) By using a soap solution instead of the
soap, as in (1).

(3) By rubbing on a wash-board.

In each case dry the cloth and compare with an original piece.

After the results of the experiments have been discussed, the pupils may
formulate a series of "points" to be observed in the washing of woollen
fabrics.

[Illustration: Cotton fibres magnified]

[Illustration: Linen fibres magnified]

[Illustration: Woollen fibres magnified]

POINTS IN WASHING WOOLLENS

1. Use lukewarm, soft water.

2. Do not use strong soaps or alkalies.

3. Do not rub soap directly on the woollen material, but use soap
solutions.

4. Do not rub or twist woollen cloth when it is wet.

5. Do not boil to sterilize.

6. Do not dry in extreme heat.

STEPS IN WASHING WOOLLEN MATERIALS

1. Shake or brush the clothing to free it from dust.

2. Put it into lukewarm, soapy water to soak for a few minutes.

3. Wash on both sides by squeezing and sousing in the water.

4. Rinse in clear, lukewarm water; use several waters, if necessary, to
remove the soap.

5. Pass through a loosely set wringer or squeeze the water out by hand.

6. Shake, in order to raise the woolly fibres.

7. Dry in a moderate temperature, in a wind, if possible.

CHAPTER X

FORM IV: SENIOR GRADE

FOOD