er, whose object is to prevent the cops from becoming detached
from the plate. This plate, full of cops, is now placed in the
dye-vessel and rests upon a flange which is provided for that purpose.
When the cop plate is in position the dye-vessel is divided into two
chambers--a lower chamber and an upper one, in the latter being the
cops.

The pump draws liquor from the chamber under the cop plate and so
creates a vacuum, which during the working of the machines ranges from
10 to 20 inches in degree. To supply this vacuum, dye-liquor is drawn
from the upper chamber through the cops. The pump returns the liquor to
the dye-vessel. A very rapid circulation of dye-liquor takes place, from
25 to 50 gallons per minute passing through the cops and pump. From five
to ten minutes is sufficient to dye the cops. The machine is simple in
its construction and gives good results, the cops being completely dyed
through. One important consideration in cop dyeing is to be able to dye
successive batches of cops to exactly the same shade, and this is quite
possible with this machine.

=Young & Crippin's Cop-dyeing Machine.=--So far as simplicity of
construction is concerned this lies between the two preceding machines.
It consists of four parts with some accessory mechanism. There is first
a dye-liquor storage tank at the base of the apparatus in which the
liquor is kept stored and boiling (if necessary) ready for use, above
this and at the front end is the dye-chamber, this communicates at its
lower end by a pipe with the dye-liquor in the dye-vat. Then there is a
large vacuum chamber, in which by means of an injector a vacuum can be
formed, this directly communicates with a liquor-receiving chamber
which again in turn is in communication with the upper part of the
dye-chamber. The cops are placed on perforated spindles as usual, and
these on a perforated plate and are kept in place by a plate which is
screwed down on them. The charged cop plate is placed in the dye-chamber
on which a cover is placed and screwed down. By means of a lever the
injector is set at work, a vacuum created in the vacuum and receiving
chambers, the consequence being that dye-liquor is drawn from the vat
through the cops in the dye-chamber into the receiving chamber. When a
certain quantity of liquor has passed through, by a movement of a lever,
the vacuum is destroyed, and the dye-liquor runs back into the dye-vat;
these operations are repeated until from past e