The Chemistry of Hat Manufacturing | Page 7

diseased, the wool suffers degradation;
also, with improvement in health follows pari passu, improvement in
the wool structure, which means increase both in number and vigour of
the scales on the wool fibres, increase of the serrated ends of these, and
of their regularity. In weakness and disease the number of scales in a
given hair-shaft diminishes, and these become finer and less
pronounced. The fibres themselves also become attenuated. Hence
when disease becomes death, we have considerably degraded fibres.
This is seen clearly in the subjoined figures (see Fig. 13), which are of
wool fibres from animals that have died of disease. The fibres are
attenuated and irregular, the scale markings and edges have almost
disappeared in some places, and are generally scanty and meagre in
development. It is no wonder that such "dead wool" will be badly
adapted for felting. "Dead wool" is nearly as bad as "kempy" wool, in
which malformation of fibre has occurred. In such "kemps," as Dr.
Bowman has shown, scales have disappeared, and the fibre has become,
in part or whole, a dense, non-cellular structure, resisting
dye-penetration and felting (see Fig. 14).
[Illustration: FIG. 13.]
[Illustration: FIG. 14.]
One of the physical properties of wool is its hygroscopicity or power of
absorbing moisture. As the very structure of wool and fur fibre would
lead us to suppose, these substances are able to absorb a very
considerable amount of water without appearing damp. If exposed
freely to the air in warm and dry weather, wool retains from 8 to 10 per
cent., and if in a damp place for some time, it may absorb as much as
from 30 to 50 per cent. of water: Wool, fur, or hair that has been
washed, absorbs the most moisture; indeed, the amount of water taken
up varies inversely with the fatty or oily matter present. Hence the less
fat the more moisture. In the washed wool, those fibres in which the
cells are more loosely arranged have the greatest absorbing power for

water. No doubt the moisture finds its way in between the cells of the
wool fibre from which the oil or fat has been removed. But I need
hardly remind you that if wool and fur are capable, according to the
circumstances under which they are placed, of absorbing so much
moisture as that indicated, it becomes (especially in times of pressure
and competition) very important to inquire if it be not worth while to
cease paying wool and fur prices for mere water. This question was
answered long ago in the negative by our Continental neighbours, and
in Germany, France, and Switzerland official conditioning
establishments have been founded by the Governments of those
countries for the purpose of testing lots of purchased wool and silk, etc.,
for moisture, in order that this moisture may be deducted from the
invoices, and cash paid for real dry wool, etc. I would point out that if
you, as hat manufacturers, desire to enter the lists with Germany, you
must not let her have any advantage you have not, and it is an
advantage to pay for what you know exactly the composition of, rather
than for an article that may contain 7 per cent. or, for aught you know,
17 per cent. or 30 per cent. of water. There is, so far as I know, no
testing for water in wools and furs in this country, and certainly no
"conditioning establishments" (1887), and, I suppose, if a German or
French wool merchant or furrier could be imagined as selling wool, etc.,
in part to a German or French firm, and in part to an English one, the
latter would take the material without a murmur, though it might
contain 10 per cent., or, peradventure, 30 per cent. of water, and no
doubt the foreign, just as the English merchant or dealer, would get the
best price he could, and regard the possible 10 per cent. or 30 per cent.
of water present with certainly the more equanimity the more of that
very cheap element there were present. But look at the other side. The
German or French firm samples its lot as delivered, takes the sample to
be tested, and that 10 or 30 per cent. of water is deducted, and only the
dry wool is paid for. A few little mistakes of this kind, I need hardly
say, will altogether form a kind of vade mecum for the foreign
competitor.
We will now see what the effect of water is in the felting operation.
Especially hot water assists that operation, and the effect is a curious
one. When acid is added as well, the felting is still further increased,

and shrinking also takes place. As already shown you, the free ends of
the scales, themselves softened by