d shades on wool are many
and various, depending not only on the particular dye-stuff used, but
often on the particular shade that is being dyed. One method, which
will yield a pale and useful tint with a particular dye-stuff, would
fail if a full shade were necessary.

The greater number of red shades are now dyed by means of the
artificial dye-stuffs, as these are much easier to dye than are the
natural dyes, and they give, on the whole, more even and brilliant
shades, while as regards fastness to milling, acids, and light they
are fully equal, and in most cases superior, to the natural dyes.

#The Direct Red Dyes.#--Of this group of red dye-stuffs, Benzopurpurine,
Titan Scarlet, Diamine Fast Red F, and Benzo Fast Red are types; many
of them have been found to be very serviceable in wool dyeing. They
may be dyed either from plain baths containing common salt or
Glauber's salt, or from baths containing common salt or Glauber's salt
and a little acetic acid.

Alkaline or soap baths do not work well as a rule, and must be avoided
in wool dyeing. Generally the dye-bath is exhausted of colour, and
full shades are easily obtained, while these reds are in general
remarkable for the evenness and uniformity of tint which can be (p. 101)
produced. The reds so dyed are, on the whole, fairly fast to soaping,
and can be used for dyeing goods that have to be milled, while their
resistance to light and air is fairly good. Benzopurpurine and Diamine
Red are more or less affected by acids, but the Titan Red and some of
the more modern reds, Diamine Brilliant Scarlet, Benzo Fast Scarlets,
are all fast to acids. The fastness to washing and light of some of
them, Benzo Fast Red, Diamine Fast Red F, Titan Red, is much increased
by adding, after the wool has been dyed, 3 per cent. of fluoride of
chromium to the dye-bath, and working a little longer.

The dyeing with these colours is done at the boil, and the goods may
be entered direct into the boiling bath without fear of uneven shades
being produced. This bath may be kept as a standing one, simply adding
as each lot is dyed the necessary quantity of dye-stuff, a little
fresh water to bring the bath up to its original volume, and a
corresponding quantity of the salt originally added. The wool can then
be entered and dyed.

In place of using salt or Glauber's salt, acetate of ammonia is an
excellent assistant for this class of dyes.

The following are some recipes for dyeing vari