that brighter shades are obtained
and the darker shades with fewer dips, while the goods are dyed
cleaner and the shades are more quickly obtained, and, we think,
somewhat faster than by the other process.

There is also the advantage that no lime or other alkali is used with
this new indigo vat. The wool should be boiled out before dipping, if
the best results and even shades are desired.

#Potash-Indigo Vat.#--This is also a fermentation vat, and is set in the
following manner: 5 lb. of madder and 4 lb. of bran are mixed with 50
gallons of water and heated for from three to four hours, until a
temperature of from 180 deg. to 212 deg. F. is attained. Then 15 lb. of
carbonate of potash are added and the liquor is allowed to cool down
to about 120 deg. F. Next 10 lb., more or less according to shade
required, of finely ground indigo is added, and the whole is left for
from forty-eight to sixty hours to ferment, being stirred up at
intervals of twelve hours. This vat ferments in much the same way as
the woad vat, and presents the same general appearances. It is not so
liable to get out of order as the woad vat, and in consequence is (p. 145)
much more easily managed. It does not, however, give such bright
shades as either of the vats previously described, but it dyes a
little quicker, and deeper shades can be produced. It is the best vat
to use where indigo dyeing is carried on at irregular intervals, also
for dyeing dark shades of navy blue and for giving an indigo bottom
for dark blues, browns and greens. Such shades stand milling and
alkalies very well.

#Soda-Indigo Vat.#--The soda-indigo vat is set in the following manner:
100 lb. bran is boiled with 200 gallons of water for three hours, then
the liquor is allowed to cool from 100 deg. to 120 deg. F. Then 20 lb.
of soda crystals, 5 lb. slaked lime, and 10 to 15 lb. ground indigo
are added, the mixture being left for two or three days to ferment,
and stirred up at intervals.

Sometimes a little more soda or a little lime is added, as may be
judged from the appearance of the vat, these appearances being
practically the same as those met with in the woad vat, which have
already been described in detail.

The soda vat closely resembles the potash vat, but is cheaper to
produce. It keeps its dyeing power longer, but is somewhat more liable
to get out of order. It is like the potash vat, easier to manage than
the woad vat, as with all the woad vats it is necessary a