Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1889-11-15
Z :
iiSeS OF COAL TAR.


r.u,,.nt Gators Extracted From Sub
stance Once Considered Worthless
The coal tar created by gas making
was for many years burned. together
with the coke, under the retorts OF
the gasworks, In order TO economics
coal and not until Hoffman,. distin-
guished German chemist, investigated
coal tar scientifically was 1t found TO
contain bodies that have since become
the basis OF the worlds great color IN
dustries. The brilliant aniline colors
now used for dyeing are all extracted
from coal. Coal tar yields, ON redis-
tillation, among other things large
amount OF volatile oil called benzole'
HOFFMAN, found that benzole, upon
proper treatment with certain chem
icaIs, yielded aniline This Is an oily
liquid. akin In its nature to the liquid
nlkaloids. nicotine from tobacco ana
CONNIE from hemlock. Hofmann also
succeeded In getting beautiful deep
magenta dye from apiline by oxida-
ton, a process In which a substance
called the oxidizer gives up some OF
it's oxygen to the body oxidized. This
ave he called rosaniline. and from IL
may be obtained every conecivab'e
shade OF color. IL Is u curious TACT
this intense dye il colorless In an alb
solutely pure state. but on uniting
with acids IL Mt once takes on us char-
acteristic vivid crimson color. Since
the most important part in the manu-
facture OK these dyes depends upon
the oxidation OF the aniline. 1t is neces-
.ary to get some common and mex
pens!ve substance for that process.
Unfortunately for the personal COM
fort OF many people. arsenic acid. one
OF our most fatal poisons, Is the sub
stance generally used. 1t Is due tt
this chemical that so many OF the lab
RIGS dyed with aniiine colors are In
furious. The dyes In themselves are
harmless. The arsenic acid Is not es
sential to the color, but after II ma
done its duty as an oxidizer, the man
ufacturer does not tako the trouble t.
remove the poison carefully from TN
dyes. The suggestion to use othe
pxidizers that ase harmless has ofte
been made. but arsenic acid Is In sue
general use that manufacturers ar
unwilling to give II I'D.
1t Is said OF Hoimann's discover
that Il was the result OF IA chance IL
had been trying the action OF nnilin
with different chemicals, and withou
cleaning his test tubes had left theI
standing In the rack. The next day
upon his return to the laboratory, b
found. to his Joy and astonishmen
that something quite unexpected ha
taken place. Beautiful crystals OF
deep magenta color had formed durir
the night in one OF the test tube
With eagerness he examined thei
but could not remember how they hi
been formed. At last IL occurred
him that this was the result OF the o
Idation OF anilinc. This was the
ginning OF Hefmann's great work up
rosaniline.
IL has also been discovered th
another body contained in coal tar G
be converted into one of the most L
portant and beautiful vegetable dy
hHoWu fH' Wy NAtN i'NN''f
madden plant (alizarine). aud sin
the discovery the prices OF madc
are so low that 1t is unremuneratlve
raise IL, and the cultivation OF
plant may be considered rs "a thing
the past Such is the wonder
growth of the discovery. 1t is
fruit OF scientific researches in orga
chemistry. conducted mostly iron
scientific point Of view.
One very important coloring mat
related to coal tar and one OF
original sources OF aniline--a prod
of MS great value IA alizarine has
TO be produced on u large scale. I
Is indigo. Adolph Baeyer. Il Germ
chemist. has shown that 1t can DO I
duced artitlcially, but at present
practical means of accomplishing
have been discovered. No doubt h
ever, IL will not be long before thi
achieved. and the cultivation OF
indigo plant will share the fate OF