COAL-TAR AND WATER-GAS TAR CREOSOTES. 5 
facture of petroleum products in competition with, the natural Amer- 
ican oils. It also contains phenoloids and tar bases. 
(2) Producer tars are those tars which are produced from bitumi- 
nous- or semibituminous coals in the manufacture of producer gas. 
They result from destructive distillation combined with a partial 
combustion of the coal, (a) Blast furnaces using coal are in effect 
practically gas producers. A small amount of tar is produced in 
them, but it is similar in composition to that made in gas producers. 
This tar is known as blast-furnace tar. (b) Mond-producer tar is 
obtained from a Mond producer using bituminous or semibituminous 
coal. Other bituminous-coal producers also yield tars. These are, 
in general, called by the name of the producer, as the Sutherland 
producer tar. 
Oil tars are the tarry fluids resulting from the destructive decom- 
position or cracking of petroleum oils. Like coal tars, these fluids 
are exceedingly complex mixtures. The character of their hydro- 
carbons depends greatly upon the temperature at which the tars 
were formed. 
Like the high-temperature coal tars, the Mgli-temperature oil tars 
are very complex mixtures of compounds. The hydrocarbons are 
chiefly of the aromatic series. Benzene, toluene, naphthalene, 
phenanthrene, and methyl anthracene have been found in them; but 
so far as is known no true anthracene has been identified in the 
American oil tars. They are further characterized by the almost 
entire absence of tar acids and tar bases, and this seems to consti- 
tute the chief difference between this type of tars and high-tempera- 
ture coal tar. 
Water-gas tar is the tar produced from petroleum oil in the carbu- 
reted water-gas machine. This tar is practically the sole represen- 
tative of high-temperature oil tars. Very small amounts of high- 
temperature oil tar are produced by the destructive distillation or 
cracking of petroleum oils in the gas retorts. A sample of such tar 
examined several years ago by the author could not be distinguished 
from water-gas tar and could be distinguished from high-tempera- 
ture coal tar only by its lack of phenoloids and tar bases. 
Low-temperature oil tars are produced in the manufacture of pintsch 
gas and are obtained as a residuum in the distillation of petroleum. 
They are characterized by an almost total absence of aromatic 
hydrocarbons and by a lack of phenoloids and tar bases. No fur- 
ther discussion of this class of tars is necessary for the purposes of 
this bulletin. 
The term creosote is properly applied to the phenoloid bodies 
obtained from wood tar after they have been freed from the hydro- 
carbons, and the term is still used in this connection by druggists. 
A secondary meaning for creosote applies to a similar product 
