Thomas County cat. [volume] (Colby, Kan.) 1885-1891, 1888-09-27
: ALUM AND ITS USES.

Times.
- ALUM AND ITS USES.
A Crystalized Substance Valuable I'm Many
Totally Different Ways.
To the popular apprehension the
word alum describes white. bitter
astringent which is sold at drug stores
and used in the household for sore
Threats and in commercial operations
as one of the chemicals employed in
dyeing. Scientifically the word de-
scribes any one of considerable num-
Der of chemical substances of different
composition, but having their in
gradients combined in the same gener-
al way. All alums contain sulphuric
acid as one ingredient and some alkali
as second, while the cOmmonest form
of alum contains aluminium as third.
The alkali may be potash. soda, am
monia or lithia, while the metallic
base may be aluminium, chromium or
iron. The commercial alum has a
potash alkali. and aluminium for its
other base. In fact the name alumni
mum is derived from alum. Other
alums take their names from their
leading bases. Thus ammonia alum
has ammonia for an alkali instead of
potash, and iron and chrome alums
have iron and chromium in place of
aluminu m.
As is well known. alum is a power
full astringent and more or less attracts
organic matter. On account of this
first quality it is largely in medical
use, and on account of the latter it is
extensively used in filtering impure
water There is hardly a town or city
in the United States Or Europe whose
water supply is contaminated with
drainage or sewage where it is not the
custom to employ the alum process for
publication. 1t has been definitely
settled by the special investigation of
the American and all the European
governments that the very small
amount of alum left in the water by the
process is not in the least injurious to
the system.
A larger use of ordinary alum is
found in dye and print works. where it
is known as mOrdant. The curious
application of this word comes from
the fact that it cites" 1t does not
bite the goods, but bites the dyes into
the goods.
A second variety is known as Ro-
man alum. which varies from yellow
to brownish red in color. 1t contains
iron and aluminium as its metallic base
1t came, originally, only from Italy, as
indicated by its name. but is now made
demand for it. 1t has had for a long
time a high reputation for its medic
inal qualities, especially in cases of
quinsy sore throat, now known as
and scientific investigation
has shown that there was some truth
in the old belief that the small amount
of iron which the Roman alum con-
tains does increase its efficacy.
At one time both Roman and ordi-
nary alum were used for picking and
preserving different kinds of meats
and fish, but in this direction alum has
been entirely displaced by refrigera-
ton. salicylic acid and other modern
methods.
A third alum is more of curiosity.
1t is chrome alum, into the compost
ton of which enters that peculiar
metal. chromium. This gives it an
beautiful color. One in
teresting use to which this alum is put
is the making of the finest green
color known. This color is OBJ
tanned by exposing an ammonia
and chromium alum to high de.
gree of heat. The heat drives out
the sulphuric acid and the ammonia,
and leaves perfectly pure and exquis-
itely beautiful chrome green color. 1t
seems a roundabout way to treat the
but it is in reality the east
est and cheapest way, for the crystal
ization of the alum frees the metal
from all impurities, and then by elimi-
mating the acid and ammonia q pure
residuum can be obtained. An inter-
esting use of this color is the printing
of greenbacks and the finest of gov
bonds.
A fourth. most important, ammonia
alum is now largely used is the manu-
facture of the finest baking powders.
Its use is based upon the remarkable
chemical action which takes place
when it is mixed withsoda in powder
and baked in the oven. By the action
of the heat the ammonia is expelled.
and the alum by its destruction neutral
ICES the action of the soda. 1t has
been a popular fallacy that the baking
powder leaves a residuum of alum in
the bread. but this, as explained, il
the opposite of the truth.-N r Aait
and Express.
a