Hastings' Dictionary of the Bible (1898)
HEARTH. The Hebrew words so translated do not, any of them, mean what we call a hearth. Thus, the "hearth" of Gen 18:6 was the heap of ashes covering the hot stones on which the bread was baked, according to the Eastern custom. See Bread. The "hearth" of Ps 102:3 means fagot as fuel; in Isa 30:14, not the hearth, but the burning mass. When we read that King Jehoiakim threw the cut leaves of Jeremiah's prophecy into the fire that was on the hearth, we are to understand that before him was a portable furnace or brazier of charcoal, Jer 36:22-23.