y fast red,
and next to the paranitroaniline red may be considered the most
important of the naphthol colours. The developing bath is a little more
difficult to make, owing to the fact that it is more difficult to get
the alpha-naphthylamine into solution. The best way of proceeding is the
following: Heat 1-3/4 lb. of alpha-naphthylamine in 10 pints of boiling
water, agitating well until the base is very finely divided in the
water, then 1-1/4 pints of hydrochloric acid is added, and the heat and
stirring continued until the base is dissolved, then the mass is allowed
to cool, 27 lb. of ice is added and 1-1/2 pints of hydrochloric acid.
When cooled down to 32 deg. to 36 deg. F., there is added 3 pints sodium nitrite
solution (3 lb. per gallon), and after allowing the diazotisation to be
completed, 4 lb. sodium acetate and sufficient water to make 13 gallons
of liquor.

The bath is used in the same manner as the previous developing baths.

_Dianisidine Blue._--Dianisidine develops with beta-naphthol, a violet
blue, which is not very fast, but by the addition of some copper to the
developing bath a very fine blue is got which has a fair degree of
fastness. The developing bath is made as follows: Mix 10-1/2 oz.
dianisidine with 7 oz. hydrochloric acid and 7-1/2 pints of boiling
water, when complete solution is obtained it is allowed to cool, then 20
lb. of ice is added. Next 1-3/4 pints of nitrite of soda solution,
containing 1-1/2 lb. per gal. and 2-1/2 pints of cold water. Stir for
thirty minutes, then add 1-1/4 pints copper chloride solution at 72 deg.
Tw., and sufficient water to make up 6-1/2 gallons.

The cotton is prepared with beta-naphthol in the usual way, and then
passed through this developing bath.

_Amidoazotoluol Garnet._--Amidoazotoluol produces with beta-naphthol a
fine garnet red in the usual way.

The developing bath is made from 14 oz. amidoazotoluol, mixed with 1-1/2
pints of sodium nitrite solution containing 1-1/2 lb. per gallon, when
well mixed add 1 pint of hydrochloric acid diluted with 2 pints water,
when this is well mixed add sufficient water to make up a gallon, then
add 1 lb. acetate of soda.

The cotton is passed through this dye-bath, then washed well, passed
through a weak acid bath, then soaped well, washed and dried.

(8) DYEING COTTON BY IMPREGNATION WITH DYE-STUFF SOLUTION.

Indigo is a dye-stuff which requires special processes for its
application to the cotton or wool fibr