e best results, as then no weakening of the dye-liquor can
take place through dilution by the condensation of the steam. Many
dye-vats are, however, fitted with perforated, or, as they are called,
open steam coils, in which case there is, perhaps, better circulation of
the liquor in the dye-vat, but as some of the steam must condense, there
is a little dilution of the dye-liquor in the vat.

DYEING MACHINES.

Dye tubs and vats, such as those described above, have been largely
superseded by machines in which the handling, or working of the
materials being dyed is effected by mechanical means. There have been a
large number of dyeing machines invented, some of these have not been
found to be very practical, and so they have gone out of use. Space will
not admit of a detailed account of every kind of machine, but only of
those which are in constant use in dye-works.

=Dyeing Loose, or Raw Cotton.=--Few machines have been designed for this
purpose, and about the only successful one is:

=Delahunty's Dyeing Machine.=--This is illustrated in Fig. 9. It
consists of a drum made of lattice work, which can revolve inside an
outer wooden casing. The interior of the revolving drum is fitted with
hooks or fingers, whose action is to keep the material open. One segment
of the drum is made to open, so that the loose cotton or wool to be dyed
can be inserted. By suitable gearing the drum can be revolved; and the
dye-liquor, which is in the lower half of the wooden casing, penetrates
through the lattice work of the drum, and dyes the material contained in
it. The construction of the machine is well shown in the drawing, while
the mode of working is obvious from it and the description just given.
The machine is very successful, and well adapted for dyeing loose, or
raw wool and cotton. The material may be scoured, bleached, dyed, or
otherwise treated in this machine.

The Obermaier machine, presently to be described, may also be used for
dyeing loose cotton or wool.

DYEING, SLUBBING, SLIVER OR CARDED COTTON AND WOOL.

[Illustration: FIG. 9.--Delahunty's Dyeing Machine.]

[Illustration: FIG. 10.--Obermaier Dyeing Machine.]

It is found in practice that the dyeing of loose wool or cotton is not
altogether satisfactory--the impurities they naturally contain interfere
with the purity of the shade they will take. Then again the dyes and
mordants used in dyeing them are found to have some action on the wire
of the carding engine t