into combination and form a colour lake that
precipitates out in the dye-bath, causing the loss of material alluded
to above, while some of it gets mechanically fixed on the cotton, in a
more or less loose form, and this looseness causes the colour to rub
off.

For a _chrome-logwood black_, a dye-bath is made with 3 lb. bichromate
of potash, 100 gallons logwood decoction at 3 deg. Tw., and 6-1/2 lb.
hydrochloric acid. Enter the cotton into the cold bath, raise slowly to
the boil and work until the cotton has acquired a full black blue
colour, then take it out and rinse in a hot lime water when a blue black
will be got.

A _copper-logwood black_ is got by taking 100 gallons logwood decoction
at 3 deg. Tw., and 6 lb. copper acetate (verdigris); the cotton is entered
cold and brought up to the boil. Copper nitrate may be used in the place
of the copper acetate, when it is a good plan to add a little soda to
the bath. Some dyers in working a copper-logwood black make the dye-bath
from 100 gallons logwood liquor at 2 deg. Tw., 4 lb. copper sulphate
(bluestone) and 4 lb. soda. This bath is used at about 180 deg. to 190 deg. F.,
for three-quarters of an hour, then the cotton is lifted out, wrung and
aged or as it is sometimes called "smothered" for five hours. The
operations are repeated two or three times to develop a full black.

Logwood black dyeing has lost much of its importance of late years owing
to the introduction of the many direct blacks, which are much easier of
application and leave the cotton with a fuller and softer feel.

_Logwood Greys._--These are much dyed on cotton and are nothing more
than weak logwood blacks, and may be dyed by the same processes only
using baths of about one-tenth the strength.

By a one-bath process 5 lb. of logwood are made into a decoction and to
this 1 lb. of copperas (ferrous sulphate) is added and the cotton is
dyed at about 150 deg. F. in this bath. By adding to the dye-bath small
quantities of other dye-woods, fustic, peach wood, sumach, etc., greys
of various shades are obtained. Some recipes bearing on this point are
given in this section.

Logwood is not only used for dyeing blacks and greys as the principal
colouring matter, but is also used as a shading colour along with cutch,
fustic, quercitron, etc., in dyeing olives, browns, etc., and among the
recipes given in this section examples of its use in this direction will
be found.

The dye-woods--fustic, Brazil wood,