COAL:
Expressed in the Bible by two words, (Prov. xxvi. 21; Isa. xliv. 12, liv. 16) and (Ps. xviii. 9 [A. V. 8]; Prov. xxv. 22). Since means "to glow" or "to burn," probably means "the glowing," and , "black coal" (compare Prov. xxvi. 21), although this distinction does not always obtain (Isa. xliv. 12, liv. 16). Of course, charcoal is always meant, which was made of tamarisk and broom, the kind formed of the thick roots of the latter () giving an especially strong and lasting heat, and being still much sought in the East (Robinson, "Biblical Researches in Palestine," i. 203; Germ. ed., iii. 683). According to Jer. vi. 29, the flame was fanned by a bellows (), probably the ancient variety worked with the feet and hands; but in a picture found in Wilkinson's "Ancient Egyptians," iii. 339, the Egyptians are shown using for that purpose long reeds protected against the flame by long metal points.
Though the coal-fire was used chiefly for cooking food, and for baking bread, meat, and fish (Isa. xliv. 19), it was also used for heating the homes. In the winter, live coals were placed in a brazier standing in the middle of the room (, Jer. xxxvi. 22; , Zech. xii. 6); in the houses of the poor they were placed in a hole in the floor. As there were no chimneys, the smoke found vent either through the door or through the grated window (), which was generally rather high in the wall (Hosea xiii. 3).
The word "coal" is often used in a metaphorical sense: II Sam. xiv. 7 speaks of the "quenching of the coal" of a man, meaning the complete annihilation of his issue; while in Prov. xxv. 22 kindness bestowed upon an enemy is called "heaping coals of fire upon his head," since it tends to waken his deadened conscience and help him to realize his wrong. Ecclus. (Sirach) viii. 10 compares the smoldering and easily roused passion of the godless man to the coal that is easily lighted and breaks forth into flame.