The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1915-07-11

Il VOTHING demonstrates the triumphs
~ of modern scientific chemistry bet
ter than the innumerable uses TO
which coal tar is put. A century ago coal
tar was considered a waste product but
today it enters into nearly every depart
ment Of life Not only has chemistry put
to a multitude of uses this waste" prod
uct, but through it and its derivatives
number of other formerly considered waste
products have been utilized.
A wide range Of colors, various burning
and lubricating oils, asphalt Photographic
developers, medicines, favors and per-
fumes are all made partly from substances
derived from coal tar, as are dyes Tor dress
material colored paper and some foods.
Before gas was introduced a new
light century ago. Frederick Accum. who
wrote one of the first books on gas light
ing, suggested the boiling Of the tar in
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.
Ii was soon found that the heavy could
be satisfactorily used as preservative for
wood that had to be fixed underground or
submerged in water and was used extern
sively in preserving piers and wharfs.
Further experiments with the lighter oil
were made by Scotch chemist, Macintosh,
who used it in waterproofing 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
naphtha 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 experiment.
ing on the artificial production of quinine.
and, using a base known as anlllne, OBJ
tanned coloring matter called mauve.
This laid the foundation for the coal tar
color industry which has developed until
today almost every color and shade or
color is derived from aniline. Aniline had
been obtained previously from the indigo
plant anil" The discovery of mauve
created a large demand for the artificial
aniline base and gave unexpected value to
benzne. 1t yielded aniline by being
treated with nitric acid and with the Dor
ings of cast iron powdered into dust.
Having done its work in the anline still,
the dust was used by the gas maker to
cleanse his coal gas from sulphur. and
then ii passed 10 the manufacturing chem
ist who burned the sulphur out OF it and
produced sulphuric acid-a cycle of opera
tons whose beginning and end was the
utilization of waste.
This method of producing color was re-
sponsible for the desolate madden fields of
France and Holland and for the loss TO
the Hindus of their long-cherished indigo
cultivation. Anthracene, one of the heavier
oils of coal tar caused the fall of the mad.
der-growing industry. The madden pro
duced violets, reds blacks. puppies and
dark browns. Anthracene was sold very
cheaply for lubricating purposes. until GER
tain chemists heated it with zinc filings
and produced alizarin. and then the secret
of the madden plant.was discovered.
In this way chemistry displaced agricul-
ture one pound of alizarin having the color
ing power of ninety pounds of madden and
the lubricating oil sold at a trif1e as waste
became a valuable coloring matter worth
$500 ton, thereby creating a vast indus
try.
In medicine and surgery coal tar has
worked wonders. Saccharin. many hundred
times the sweetening power Of sugar. is
used by diabetic patients Carbolic acid is .
separated from the oil of coal tar by sue
cessive Installations. and in surgical opera
lions a spray of germ-killing carbolic acid
is used. Quinoline. antipyrine and other
feverassuagers are made from coal tar and
various antiseptics and food preservatives
also are obtained from it.
Vanilla favoring for cooking. which for
mery was prepared from a bean. can now
be obtained from the vanllin of the gas
works, and even this vanillin can be made
into a heliotrope perfume by adding oil of
almonds. while the latter can be produced
by treating benzine with an acid. Huge
quantities of this oil are used in the max
ing Of scented soaps