ble to give a developing bath that
froths in working, especially if much acid has been left in the cotton
from the diazotising bath. The proportions are: 10 lb. resorcine, 25 lb.
caustic soda lye of 70 deg. Tw., and 60 gallons of water; or 10 lb.
resorcine, 20 lb. soda ash, and 60 gallons of water, heated until a
solution is obtained. In the developing bath 1 per cent. of resorcine is
usually sufficient to use. It develops an orange with Primuline.

Developer F (Bayer) is a mixture of resorcine and soda ash. It requires
1-1/2 per cent, to make a developing bath.

=Phenol=, better known as carbolic acid, finds a use as a developer. It
is dissolved in caustic soda, 10 lb. phenol, 15 lb. caustic soda lye of
70 deg. Tw., and 60 gallons of water. Generally 1 per cent. is sufficient to
use as a developer. It is often called yellow developer.

=Naphthylamine ether= is used as a developer for blues in conjunction
with the Diamine blacks. It is prepared for use by dissolving in
hydrochloric acid, 10 lb. naphthylamine ether powder heated with 5 lb.
hydrochloric acid and 50 gallons water. About 1-1/4 per cent. is
required to form a developing bath. Naphthylamine ether is also sent out
in the form of a paste mixed with acid, and containing about 25 per
cent. of the actual developer.

=Fast blue developer A D= (Cassella), is amidodiphenylamine. It is
insoluble in water, but soluble in dilute acid, 10 lb. fast blue
developer A D, 5 lb. hydrochloric acid and 35 gallons of water making
the bath. To develop full shades 1 to 1-1/2 per cent, is required.

=Blue developer A N= (Cassella). The base of this is insoluble in water,
but dissolves in soda, and is probably a naphthol-sulpho acid. The
product, as met with in the market, is soluble in water, and 27 lb.
dissolved in 20 gallons of water form the bath. To produce full shades
1-1/2 per cent, is usually required.

=Phenylene diamine= is a most important developer. It comes into the
market in two forms, as a powder, very nearly pure, made into a solution
by dissolving 10 lb. with 20 gallons of water and 5 lb. hydrochloric
acid, and as a solution prepared ready for use. Developer C (Bayer) and
developer E (Bayer) are preparations of diamine, the former in a powder,
the latter in a solution. Phenylene diamine can be used with the
addition to the developing bath of acetic acid or soda.

=Schaeffer's acid= is a sulpho acid of beta-naphthol, and is dissolved
by taking 10 lb. of the aci