wed
by washing in tepid water to dissolve the potash salts, leaving the
dirt to fall away when the other substances are no longer present. To
work this method with safety requires a costly and intricate plant
with skilled supervision. The method which is practically in universal
use is washing the wool in alkaline solutions, properties of which
combine with and reduce the impurities to a lathery emulsion which is
easily washed off from the wool.

Great stress is laid upon the necessity of care in the washing
process, as the luster may be destroyed and a brownish-yellow tint
given to the wool, the spinning properties very seriously injured, the
softness destroyed, or the fiber dissolved. Some wools are easy to
wash, requiring little soap and a reasonable temperature; other wools
are cleansed with great difficulty. A note, therefore, should be made
of any particular brand or class of wool requiring special attention,
to serve as a guide in the treatment of future lots. The danger lies
in using unsuitable agents,--hard water, excessive temperatures,
strong reagents, etc.

Caustic alkalies have a most destructive effect on wool as they eat
into it and destroy its vitality. Carbonate alkalies are less severe.
Whatever cleansing substances are used, it is essential that they
should be free from anything that is likely to injure the wool--that
they remove the impurities and still preserve all the qualities in the
wool. If the washing is properly performed the alkaline portion of the
yolk is removed, leaving only the colorless animal oil in the fiber.
If the work is not thoroughly done the wool passes as "unmerchantable
washed." "Tub washed" is the term applied to fleeces which are broken
up and washed more or less by hand. Scoured wool is tub washed with
warm water and soap, and then thoroughly rinsed in cold water until
nothing remains but the clean fiber.

[Illustration: DEGREASING PLANT--REMOVING GREASE FROM WOOL]

An improved method of washing wool by hand is to have a series of
tanks with pressing rollers attached to each tank: the wool is
agitated by means of forks, and then passed to the pressing rollers
and into each tank in succession. The tanks are usually five in
number, and so arranged that the liquor can be run from the upper to
the lower tank. Upon leaving the pressing rollers the excess of water
is driven off in a hydro extractor[11] and the wool is beaten into a
light, fluffy condition by means of a wooden