Hastings' Dictionary of the Bible (1898)
LEAD, a metal known to the ancients from a very early period, and alluded to in Ex 15:10 on account of its weight. It is mentioned several times in Scripture as entering into the process of purifying more precious metals, Jer 6:29; Eze 22:18, Ruth 4:20; for which purpose quicksilver is now used. " refer to the custom of pouring molten lead into letters carved in the rock in order to make them more striking to the eye.