The New International Encyclopædia/Bituminous Coal
BITU′MINOUS COAL (Lat. bituminous, from bitumen, a kind of mineral pitch, bitumen). A term applied to the varieties of coal which contain a large percentage of volatile matter. They yield, by destructive distillation, a considerable quantity of gas, easily purified, and with good illuminating qualities, and are consequently largely used for that purpose. Some varieties also cake when heated out of contact with the air, and yield a hard, porous product known as coke. See Coal; Coke.