Food colourings not actually based on coal tar Coal tar, the black viscous liquid left over when coal is cooked to make coke, became the source for scientific experimentation around 150 years ago ...

By distilling bituminous coal in retorts to obtain gas for illumination, or by burning it in kilns or pits, the residue left behind is called coke, which is simply coal charcoal, and is nearly ...

From the column: "a robust domestic steel industry is vital for national security, as steel is a primary material for ...