er be variable in
thickness, here and there along these lines of least resistance will be
found certain twists, and it is the same kind of twists which can be so
distinctly seen as the cotton fibre is viewed through the microscope.
They are exceedingly irregular in number, on equal lengths of the same
single fibre. When they run for some length, and are fairly regular, the
edges appear like wavy lines or corrugations. It will now be seen by
the reader why these twists are so invaluable in spinning: locking and
intertwining with each other, they materially assist the spinner in
building up a long and continuous thread.

Image: FIG. 7.--Transverse and longitudinal sections of cotton fibre.

Then, too, are to be seen lying close to the regularly twisted fibres a
number of others which are very like ribbons, with here and there an
apology for a twist, and further, a careful scrutiny will be rewarded by
finding in what is reputedly the best cotton a number of filaments which
do not display any twists whatever and are very much like the round
tubing referred to a little while ago. Others again are quite flat,
without any distinguishing twists whatever. These are said to be the
half-ripe and unripe fibres, and give much trouble later on (if worked
up with good cotton) to the dyer and spinner.

As the slide containing the cotton is moved laterally, it will be seen
that this twisting of the fibre is continued for almost the whole
length, and as many as 300 twists have been counted on a single
filament. In some, the fibre tapers slightly, becoming more and more
cylindrical as the end most remote from the seed is approached, until it
is quite solid. These stiff ends soon disappear after the cotton has
been treated in the early processes of manufacture. Thus there may be
found in almost every sample of cotton what are called ripe, half-ripe
and unripe cotton. The last-named kind result from--

1. Gathering the crop before the boll is properly ripened and
matured.

2. Bad seasons; too much moisture and too little heat.

Then again in the same boll all fibres do not ripen together just as all
apples on the same tree do not ripen together.

Immature or unripe cotton cannot be dyed, and when small white specks
are seen in any dyed fabric they are often due to the fact that unripe
cotton has been used in the manufacture of the cloth.

=Measurement of the Cotton Fibre.=--This is not at all a difficult matter,