This black is a very fine one, and
is very fast.

_Violet Black on Wool_.--Make the dye-bath with 4 lb. Naphthylamine
Black D, 10 lb. Glauber's salt, and 5 lb. acetic acid. This black is
pretty fast to acids, alkalies and light, but is somewhat loose to
soaping, and, therefore, cannot be used for black goods that have to
be strongly milled. Naphthylamine Black 4 B dyes somewhat bluer shades
than the B brand.

_Blue Black on Wool_.--Prepare the dye-bath with 6 lb. Victoria Blue
Black, 20 lb. Glauber's salt, and 1-1/2 lb. acetic acid, working at
the boil for one hour. A fine blue black, is obtained which is quite
fast to acids, washing and light.

_Greenish Black on Wool_.--The dye-bath is made with 3 lb. Victoria
Black Blue, 2 lb. Fast Yellow F Y, 20 lb. Glauber's, salt, and
1/1-2 lb. acetic acid. The dyeing is done at the boil and takes about
an hour. This shade has a good full tone, and is fast.

_Jet Black on Wool_.--Make the dye-bath with 4 lb. Victoria Black B,
1/2 lb. Fast Yellow F Y, 10 lb. Glauber's salt, and 2 lb. sulphuric
acid, working at the boil for one hour. A very fine shade is thus
obtained, which is fast to acids, alkalies and soaping. By omitting
the Fast Yellow a blue black is obtained, while by using Acid Green
instead a greener tone is given to the black. In place of the Victoria
Black B the two other brands, 5 G, and G, of these blacks may be used.
These give equally fast blacks of a deeper and more jet black.

_Black on Wool_.--Prepare a bath with 5 lb. acetic acid, 9 deg. Tw.;
enter the wool for one hour, then lift and add 5lb. Naphthol Black 3 B,
and 1/4 lb. Indian Yellow. Re-enter the goods and boil for one hour,
wash and dry.

Many of the black dyes--Naphthol Black, Naphthylamine Blacks, (p. 092)
Naphthyl Blue Black N, Acid Black B, etc.--are capable of slowly dyeing
wool from neutral baths, that is, containing only Glauber's salt, or
rather more quickly if a little acetic acid be present. Such dyes are
very useful for dyeing heavily milled or felted fabrics, such as hat
bodies for instance, as then the dye possesses greater penetrative
properties and passes more into the substance of the fabric, which is,
therefore, better dyed through. Also they are suitable for dyeing
half-wool fabrics as will be seen on referring to the chapter dealing
with the dyeing of union or cotton-wool fabrics.

It is quite possible to dye a black on wool by using a combination of
acid and azo dye-stuffs