the cop form for placing in the shuttles. The cop form is
that in which the yarn leaves the spinning frame, and necessarily apart
from the dyeing there is labour involved in reeling it into hanks and
winding it back again into the cop form, not only so but there is
necessarily some waste made in these operations. Many attempts have been
made, with more or less success, to dye the yarn while in the cop form
and so save the cost of the hanking and copping above referred to as
well as the waste which occurs. Cops cannot be satisfactorily dyed by
simple immersion in a boiling dye-bath, the outside becomes dyed but the
central portions as often as not remain quite white, and there is a
distinct grading of colour or shade throughout the cop, the outer
portions being deeply dyed while the middle portion will only have a
medium shade and the central portions either not being dyed at all or
only faintly tinted, much depending on the firmness with which the cop
has been wound. A soft, loosely wound cop is much more thoroughly dyed
than a hard, tightly wound cop. This uneven dyeing of the cops is not
satisfactory, and must be avoided if cop dyeing is to be a success. Many
dyers have turned their attention to this question of dyeing yarn in the
cop form, and many machines have been devised for the purpose; some of
these have not been a success, but a few have been found to yield
satisfactory results and proved in practice very successful.

In all machines for dyeing cops one principle has been adopted--that of
drawing or forcing the dye-liquor through the cop.

[Illustration: FIG. 13.--Graemiger Cop-dyeing Machine.]

=Graemiger's Cop-dyeing Machine.=--This is shown in section in Figs. 13
and 14. Although simple in its work it is somewhat complex in its
construction and difficult to describe. The machine consists of a
dye-vat to hold the requisite dye-liquors. In the upper portions of this
is an iron casting formed with four chambers, the two lower ones of
which are immersed in the dye-liquor while the upper chambers are above
it. The sides of this casting are formed of metal plates which fit
tightly against the casting and form as nearly air-and water-tight
joints with it as it is possible to make. These metal plates are on a
spindle and can be rotated. They are perforated and made to carry
spindles, on which are placed the cops to be dyed. The two lower
chambers are in connection with a pump which draws the air from them and
so