xperience of the working
of the machine it is thought sufficient has passed through to dye the
cops, when the dye-chamber is opened and the cops taken out. This
machine works very well.

=Mommer's Cop-dyeing Machine.=--This is in use in several continental
dye-works. The central portion of this machine is a rectangular
dye-chamber, which can be hermetically closed by hinged doors, the cops
are placed side by side on trays provided with perforated bottoms, the
trays being placed one on the top of the other in the dye-chamber. From
the top of the dye-chamber passes a pipe to a centrifugal pump, and a
similar pipe passes from the bottom of the chamber to the pump. A
separate vat contains the dye-liquor which is used. The pump forces the
dye-liquor through the cops which take up the dye. Arrangements are
provided by which the direction of the flow of the dye-liquor can be
changed. This machine gives fairly good results, not perhaps equal to
those with the machines previously described.

=Warp-dyeing Machines.=--Although many warps, especially for fancy
fabrics, are prepared from yarns dyed in the hank or cop form, yet it
is found advantageous when a warp is of one colour, a self-colour as it
is called, to form the warp from grey or white yarns and to dye it after
warping. If the warp were so wound as to be able to go into a Obermaier
dyeing machine, it would be possible to dye it in that machine, but
generally warps are dyed in the open form and are passed through a
dyeing vat, commonly called a warp-vat which is constructed as shown in
Fig. 16. These warp-dyeing machines generally consist of a long
rectangular wooden dye-vat, divided by two partitions into three
compartments, each provided with steam pipes to heat up its contents;
between the first and second and between the second and third
compartments is fitted a pair of squeezing rollers, while the third
compartment is fitted with a heavier pair of squeezing rollers. Motion
is given to these rollers by suitable gearing, and they serve to draw
the warp through the machine. Guide rollers are fitted in the
compartment, and the warp being taken round these, it passes several
times up and down and through the dye-liquors contained in the
compartments. These warp-dyeing machines may be made of sufficient width
to take one, two, three or more warps at one time as desired.

[Illustration: FIG. 16.--Warp-dyeing Machine.]

The three compartments of the machine may contain di