scales interlock (see Fig. 9), and thus the fibres are held together.
Just as with hair, the scales of which have their free edges pointing
upwards away from the root, and towards the extremity of the hair, so
with wool. When the wool is on the back of the sheep, the scales of the
woolly hair all point in the same direction, so that while maintained in
that attitude the individual hairs slide over one another, and do not
tend to felt or mat; if they did, woe betide the animal. The fact of the
peculiar serrated, scaly structure of hair and wool is easily proved by
working a hair between the fingers. If, for instance, a human hair be
placed between finger and thumb, and gently rubbed by the alternate
motion of finger and thumb together, it will then invariably move in the
direction of the root, quite independently of the will of the person
performing the test. A glance at the form of the typical wool fibres
shown (see Fig. 10), will show the considerable difference between a
wool and a hair fibre. You will observe that the scales of the wool
fibre are rather pointed than rounded at their free edges, and that at
intervals we have a kind of composite and jagged-edged funnels, fitting
into each other, and thus making up the covering of the cylindrical
portion of the fibre. The sharpened, jagged edges enable these scales
more easily to get under the opposing scales, and to penetrate inwards
and downwards according to the pressure exerted. The free edges of the
scales of wool are much longer and deeper than in the case of hair. In
hair the overlapping scales are attached to the under layer up to the
edges of those scales, and at this extremity can only be detached by
the use of certain reagents. But this is not so with wool, for here the
ends of the scales are, for nearly two-thirds of their length, free, and
are, moreover, partially turned outwards. One of the fibres shown in
Fig. 10 is that of the merino sheep, and is one of the most valuable and
beautiful wools grown. There you have the type of a fibre best suited
for textile purposes, and the more closely different hairs approach