St. Johnsbury Caledonian. [volume] (St. Johnsbury, Vt.) 1867-1919, 1915-08-18
MAGIC COAL TAR.
Once DespiSed, 1t Is Now a Source
of LimitIeSS Products.
SPANS THE WORLD OF COLOR.


and Is Used In Practically Every In
dustry-In Medicine and Surgery,
Also, IL Has Worked Wonders.
Among the almost limitless number
Of natural products of this country
coal tar stands well in the lead in the
variety of uses to which it may be ap-
piled. Evil smelling, it is the rough
material from which many valuable
substances have been obtained after
years of persistence by science and in
dustry.
These substances include a wide
range of coIors, various burning and
lubricating oils, asphalt for pavements,
Photographic developers and a great
number of medicines, favors and per-
fumes. Coal tar is used In practically
every manufacturing process where
dyes are needed, in making cloths,
silks, dress materials, colored papers
I and even colored articles of food.
About a century ago coal tar was
considered almost waste product, and
no one had thought it worth while to
experiment with it. At that time gas
was being introduced as a new light,
and Frederick Accum, who wrote one
of the first books on gas lighting, sug
gested the boiling of the tar in a still
and the condensation and collection of
the volatile products. The experiment
was made, and the process yielded two
oils One was heavy and the other
light. 1t was soon found that the
heavy could be satisfactorily used as a
preservative for wood that had to be
fixed underground or submerged in
water and was used extensively in pre-
serving piers and Wharfs
Further experiments with the lighter
oil were made by a Scotch chemist,
Macintosh, who used it in waterproof
| ing the clothing which still bears his
name 1t also is used as a solvent in
varnish making and as coal naphtha
for lighting. Experiments with naph-
tina disclosed rich treasury of colors
which for centuries had been locked up
in coal and it's refuse-tar. Benzine
was extracted from naphtha and this
in turn produced the different shades
Of violet, green, blue and yellow. Later
another chemist made the commercial
manufacture of benzine possible. He
was experimenting on the artificial pro-
ductiOn of quinine, and, using a base
known as aniline, obtained the coloring
matter called mauve.
This laid the foundation for the coal
tar color industry which has develop
ed until today almost every color and
shade of color is derived from aniIine.
At 10 --I-x
from the indigo plant anil" The dis
covery of mauve created a>Iarge de-
mand for the artificial aniline base
and gave unexpected value to benzine.
1t yielded aniline by being treated with
nitric acid and with the borings of cast
iron powdered into dust. Having done
its work in the aniline still, the dust
was used by the gas maker to cleanse
his coal gas from sulphur, and then it
passed to the manufacturing chemist,
who burned the sulphur out of it and
produced sulphuric acid-a cycle Of OPP
erations whose beginning and end was
the utilization of waste.
This method of producing color was
responsible for the desolate madden
fields of France and Holland and for
the loss to the Hindus of their long
cherished indigo cultivation. Anthra-
Gene, one of the heavier oils of coal
tar, caused the fall of the madden
growing industry. The madden pro-
duced viOlets, reds, blacks, puppies and
dark browns. Anthracene was sold
very cheaply for lubricating purposes |
until certain chemists heated it with
zinc filings and produced alizarin, and
then the secret Of the madden plant |
was discovered.
In this way chemistry displaced agri-
culture, one pound of alizarin having
the coloring power of ninety pounds of |
madden, and the Iubricating oil sold at |
a trif1e as waste became a valuable |
coloring matter worth $500 a ton, |
thereby creating a vast industry.
In medicine and surgery coal tar has
worked wonders Saccharin, many hun |
bred times the sWeetening power of |
sugar, is used by diabetic patients |
Carbolic acid is separated from the oil |
of coal tar by successive Installations, |
and in surgical operations spray of |
germ killing carbolic acid is used. |
Quinoline, antipyrine and other fever |
are made from coal tar, and |
various antiseptics and food preserva
tiVes also are obtained from it.
Vanilla flavoring for cooking, which |
formerly was prepared from bean, |
can now be obtained from the vanillin |
of the gas works, and even this vanil- |
lin can be made into a heliotrope per-
fume by adding oil of almonds, while |
the latter can be produced by treating |
benZine with an acid. Huge quanti- |
ties of this oil are used in the making
Of scented soaps. As a matter Of fact
there is scarcely department of life
into which the products of coal tar do
not o,,4o. York Times