the air for some hours, next to pass through lime water to fix the iron,
and then to dye as before.

_Continuous Process._--In this case a continuous dyeing machine is
provided, fitted with five to six compartments. The cotton is first of
all prepared by steeping in a bath of 12 lb. myrabolam extract for
several hours, then it is taken to the continuous machine and run in
succession through nitrate of iron liquor, lime water, logwood and
fustic, iron liquor and water. The nitrate of iron bath contains 2
gallons of the nitrate to 10 gallons of water, and as the pieces go
through fresh additions of this liquor are made from time to time to
keep up the volume and strength of the liquor to the original points.

The logwood bath is made from 10 lb. logwood extract and 1 lb. fustic
extract, and it is used at about 160 deg. F. The quantities here given will
serve for 100 lb. of cotton, and it is well to add them dissolved up in
hot water in small quantities from time to time as the cotton goes
through the bath.

The iron liquor given after the dyeing contains 2 lb. of copperas in 10
gallons of water.

Between the various compartments of the machine is fitted squeezing
rollers to press out any surplus liquor, which is run back into the
compartment. The rate of running the warp or pieces through should not
be too rapid, and the dyer must adapt the rate to the speed with which
the cloth dyes up in the dye-bath.

The addition of a little red liquor (alumina acetate) to the iron bath
is sometimes made, this is advantageous, as it results in the production
of a finer black. Iron by itself tends to give a rusty-looking, or
brownish black, but the violet, or lilac shade that alumina gives with
logwood, tones the black and makes it look more pleasant.

Some dyers add a small quantity, 1 per cent., of the weight of the
cotton of sulphate of copper to the iron bath, others add even more than
this. Some use nitrate of copper; the copper giving a greenish shade of
black with logwood, and this tones down the iron black and makes it more
bloomy in appearance.

Single bath methods of dyeing logwood blacks are in use, such methods
are not economical as a large quantity, both of dye-wood and mordants,
remain in the bath unused. Although full intense blacks can be dyed with
them, the black is rather loosely fixed and tends to rub off. This is
because as both the dye-stuff and the mordant are in the same bath
together they tend to enter