to light, alkalies and acids. Diamond Black by itself gives bluish
shades. This dye is much used in the hat-dyeing trade.

_Violet Black_.--Mordant the wool by boiling for one and a half hours
in a bath made with 3 lb. fluoride of chrome and 1 lb. oxalic acid,
then rinse and dye in a bath containing 25 lb. Alizarine Cyanine
Black G, 5 lb. acetate of ammonia, and 1 lb. acetic acid, working at
the boil for one and a half hours. A fine full shade is obtained (p. 094)
which is quite fast to acids, milling and light.

_Brown Black_.--Mordant the wool as in the last recipe, then dye in a
new bath 25 lb. Alizarine Cyanine Black G, 3 lb. Anthracene Brown,
5 lb. acetate of ammonia, and 1 lb. acetic acid, working at the boil
for one to one and a half hours.

_Jet Black_.--Mordant as in either of the above recipes, then dye in a
bath containing 20 lb. Alizarine Black S W, and 2 lb. acetic acid.
This black possesses a great degree of resistance to acid, alkali,
milling and light, and is one of the best blacks at the disposal of
the dyer.

_Reddish Black on Wool_.--Prepare the dye-bath containing 5 lb.
Chromotrop 2 B, 10 lb. Glauber's salt, and 4 lb. sulphuric acid, work
at the boil for one hour, then lift. Add to the same bath 3 lb.
bichromate of potash and 1 lb. sulphuric acid, and work half an hour
longer.

_Blue Black_.--Make the dye-bath with 6 lb. Chromotrop 10 B and 4 lb.
sulphuric acid; dye, and develop the black by adding to the same bath
3 lb. bichromate of potash and 1 lb. sulphuric acid.

_Jet Black_.--Prepare the dye-bath with 5-1/2 lb. Chromotrop S,
1/4 lb. Alizarine Yellow G G W, 10 lb. Glauber's salt, and 4 lb.
sulphuric acid. Slowly raise to the boil and work for one hour, then
add to the same dye-bath 3 lb. bichromate of potash, and 1 lb.
sulphuric acid, working at the boil for one hour.

These are but a few examples of how the Chromotrops (one of the most
interesting series of dye-stuffs at the service of the dyer) may be
used to dye blacks. They of themselves dye brilliant reds, from bright
scarlet (2 R), crimson (6 B), and purple (8 B and 10 B), to maroon and
clarets (S and S B). These being turned black on being chromed, give
various shades--blue blacks, violet blacks, and jet blacks, which have
the merit of being fast to acids, strong milling, and light in a
great degree. The blue and violet blacks may be converted to jet (p. 095)
shades by adding to the dye-bath some yellow dye-stuff, such as Azo