HEARTH, the part of a room where a fire is made, also the fire and cooking apparatus on board ship; the floor of a smith's forge, or of a reverberatory furnace on which the ore is exposed to the flame ; the lower part of a blast furnace through which the metal goes down into the crucible ; in soldering, a portable brazier or chafing dish, and an iron box sunk in the middle of a flat iron plate or table. An "open-hearth furnace" is a regenerative fur nace of the reverberatory type used in making steel, hence "open hearth steel" (see IRoN and STEEL).