Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1873-12-10
Scientific.

PRINTING WITH ANILNR BLACK
When ammonia is added in excess to .
solution of alum, q gelatinous precipi-
tate Is formed which consists OF the
hydrsted oxide of aluminium. This
hydrate is soluble in acids, acting In
that case as base, but it is also solu-
BILE in caustic soda and potash, when it
acts as a weak acid and forms salts
known as aluminates of soda and pot
ash. The illuminate of soda can be
prepared very cheaply, and is advan-
tageously employed, according to DR..
A. Kielmeyer, for coating the cloth
placed under the calico and running
along with it. In calico printing por-
ton, of course, of the color or mordant
employed passes entirely through the
cloth which is being printed and to
prevent it from being deposited on the
pressure rollers and returned to q clean
part of the cloth upon the second revo-
luton, il is customary to have q piece
of thick woolen cloth "a little wider
than the calico, running between the
calico and roller to take up this eIcess)
and to pass it over one OF the heated
cylinders it is thus dried and can be
used two or three times before it has to
be cleaned. The great expense Of these
travellers" and the labor of cleaning
them has induced several calico prin-
ters to substitute a piece of the un-
bleached cotton cloth. After being
used once it can be bleached and is in
no way injured for calico, except in one
particular case. A piece of unbleached
muslin which has been soiled by aniline
black cannot be entirely cleaned by the
bleaching process, and, moreover, the
fiber is injured. For this reason it has
been necessary to adhere to the old
method of expensive wooden traveller"
when using aniline black.
Dr. Kielmeyer has, however, made
the interesting discovery that illuminate
of soda mixed with scorched starch
prevents the aniline black from attach
ing itself to the cotton. The alkalinity
of this substance prevents the black
from being developed and at the same
time, the solid hydrate of alumina Is
formed where aniline black and alumni
nate of soda come In contact, and pro-
tects the fiber by preventing the black
from coming in contact with it. At
tempts to employ the carbonate and
acetate of alumina for the same purpose
have not succeeded we'll for although
they check the development of the
black, they do not form that insoluble
layer which protects the fiber.
preparing the goods, the unbleached
as soon as it is singed, is passed
twice through q cold solution of alumni
nate of soda of or 50 B. 1t is left un-
rolled for two hours that it may become
evenly distributed throughout the
goods, and then dried on the hot cylin-
ders. The cost of material for prepar-
ing a piece 164 feet in length is, in
about 4 cents. For light
patterns, like shirtings, it can be used
over two or three times, for heavier
ones but once; and if the pattern is
very heavy, a solution of 10' B. should
be employed. Before proceeding to
bleach them, they are placed in a
muriatic acid solution of % B. and
washed. After bleaching there will be
no trace left of the black. 1t has also
been observed that the black patterns
printed over this background do not
strike through the goods SO much as
otherwise, and consequently the fabrics
are not weakened SO much; but upon
the right side they are perfectly bright
and full. Even this latter is of no
small account when We remember that
all aniline black, if never so carefully
has more or less tendency to
rot or weaken the fiber.