Iron Furnace

Iron Furnace. . , Across the Gale River stands New Hampshire's sole surviving blast furnace. It is unusual, as well, in its octagonal shape and its remarkable condition. , A huge wooden shed protected the furnace and workers from the weather. The shed filled the area between the river and the upper terrace in the rear. , Iron ore was hauled in two-wheeled oxcarts from mines three miles to the southwest. The rusted wheelbarrow displayed nearby was used to feed charcoal, iron ore and limestone into the furnace from above. , Once started, the fire was kept roaring for four to six months. Air pumped from water-powered bellows fanned the coals. In later years, hot air was drawn off the top and piped down to the coals – the hot blast method. , When the iron ore melted, impurities floated to the top. This "slag" was drawn off the surface of the molten mass. Every 24 hours a clay plug near the bottom was removed, allowing liquid iron to flow into sand furrows and form iron bars called "sows" and "pigs." , Residents for miles around could see the reflected glow from the red-hot iron. , Some of the pig iron was remelted at a refining forge and converted to wrought iron. This malleable iron could be reheated and hammered into products by blacksmiths and foundrymen, or molded into iron bars. , Other pig iron was cast directly at the furnace into kettles and heating stoves, which were sold in the company stores here and in Bath, New Hampshire. , Iron pigs and products were shipped south on the Connecticut River from Bath. , The furnace and its site are privately owned. Trespassing is dangerous and forbidden. .