action of an injector or centrifugal pump to scour the yarn; then water
is circulated by means of a centrifugal pump for washing. The chemic and
sour liquors are circulated also by means of pumps, so that without the
slightest disturbance to the yarn it is quickly and economically
bleached.

[Illustration: FIG. 5.--Mather & Platt's Yarn-bleaching Kier.]

STAINS AND DAMAGES IN BLEACHED GOODS.

Some of the stains in bleached goods which are met are beyond the
control of the bleacher to avoid, while others are due to various
defects in the process. Now the subject of stains can only be dealt with
in a very general way, because of the varying manner in which they
arise. The recognition of the particular way in which the stains have
been formed is sometimes difficult to discover. First, there are iron
stains, which are the most common kind of stains that a bleacher is
troubled with. These generally make their appearance in the form of red
spots of greater or less extent. As a rule they are not visible before
the pieces are fully bleached. Their origin is varied. Sometimes they
arise from the machinery; if the kiers are not kept thoroughly
whitewashed out, there is a great liability to produce iron stains.
Every other machine which is used in the process is made of iron, and
should be kept free from rust, or the chances of stains are considerably
increased. The water used in the bleaching must be free from iron. A
small trace will not make much difference, but some waters contain a
great deal of iron, so much so that they are absolutely unusable for
bleaching purposes. Iron stains are often due to a very curious cause:
the dropping of the oil used in the spinning or weaving machinery on to
the cotton during the process of manufacture. This oil is often charged
with iron derived from the wear and tear of the machinery, and which
often gets fixed in the form of red spots of oxide on the fibre. Iron
stains cannot readily be extracted.

Oil stains are also common. These take the form of bright yellow stains
in various shapes, sometimes extending along the piece in streaks, at
other times in patches in various places about the piece. Generally
these oil stains do not make their appearance as soon as the piece is
bleached, and often the bleacher sends out his goods quite white and
apparently all right, and yet soon afterwards comes a complaint that the
goods are stained yellow. One cause of these yellow oil stains can be
tra