Coal tar is a brown or black liquid of extremely high viscosity. Coal tar is among the by-products when coal is carbonized to make coke or gasified to make coal gas. Coal tars are complex and variable mixtures of phenols, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic compounds, about 200 substances in all.
Read more about Coal Tar: Safety, Coal Tar Distillers
Famous quotes containing the words coal and/or tar:
“Coal lay in ledges under the ground since the Flood, until a laborer with pick and windlass brings it to the surface. We may will call it black diamonds. Every basket is power and civilization. For coal is a portable climate.”
—Ralph Waldo Emerson (1803–1882)
“The mob is man voluntarily descending to the nature of the beast. Its fit hour of activity is night. Its actions are insane like its whole constitution. It persecutes a principle; it would whip a right; it would tar and feather justice, by inflicting fire and outrage upon the houses and persons of those who have these. It resembles the prank of boys, who run with fire-engines to put out the ruddy aurora streaming to the stars.”
—Ralph Waldo Emerson (1803–1882)