Stories from PA History
The Pennsylvania Iron Industry: Furnace and Forge of America
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The Pennsylvania Iron Industry: Furnace and Forge of America
Chapter 1: Growth of the Charcoal Iron Industry, 1716-1840

Ironmaster's house and ruins.
Ironmaster's house and ruins.
Iron manufacturing grew enormously in Pennsyvania, from a single bloomery forge in 1716 to more than 200 charcoal furnaces across the state in 1840. This expansion came in response to rising demand for iron as population spread and markets widened. In this period of rapid growth, however, two critical aspects of the industry changed little. The iron industry remained very rural, and it remained wedded to the charcoal iron furnace.

In 1716 markerThomas Rutter erected the first ironworks in Pennsylvania, a bloomery forge along a tributary of the Schuylkill River where workers heated ore and hammered iron into small iron blooms. About 1720, Rutter and his partners erected the colony's first iron furnace, markerColebrookdale Furnace, which made better-quality iron more efficiently than a bloomery forge. Although this charcoal furnace utilized proven British technology, it was still an early experiment in making iron in the young colony. Its success opened the way for others.

Image of Iron workers and their family.
Iron Forge, by Joseph Wright, January 1, 1773.
Subsequent ironmasters expanded the industry through much of Pennsylvania before 1840. As the population in Philadelphia and southeastern and south-central Pennsylvania grew in the 1700s, so did demand for a wide variety of iron products. John Taylor, who erected Sarum Forge (later renamed markerGlen Mills)in Delaware County in 1739, was one of the many ironmasters who sought to supply the growing market in the Delaware River valley. Ironworks appeared first in the Schuylkill and Delaware River valleys, then in Lancaster County and the Susquehanna valley.

During the 1790s, as settlers moved into central Pennsylvania, ironmasters began to develop the markerJuniata Iron region, which had rich ore deposits. markerFurnaces and forges in this region sold products locally, as well as to far-off Pittsburgh. About 1790 the markerAlliance Furnace emerged in Fayette County, one of the first iron furnaces west of the Alleghenies. Other ironmasters soon expanded the industry into western Pennsylvania. By 1815 Pittsburgh called itself "The Birmingham of America." By 1840, it was a major manufacturing center for a wide range of forged and rolled products.

Image of the furnace complex and workers.
The charcoal-fueled furnace was at the heart of an extensive iron plantation.
Ironmasters located furnaces and forges in rural areas to take advantage of iron ore deposits, vast forests that provided charcoal fuel, and streams that powered ironworks. Locating furnaces near ore deposits was most critical, since these deposits were less common than forests and streams. markerCornwall Banks in Lebanon County was the most important and largest iron ore deposit in Pennsylvania. A furnace also used up large tracts of forest to make charcoal. Ironmasters often located forges, slitting mills, and rolling mills near iron furnaces since furnaces supplied requisite pig iron.

Furnaces were primary producers of pig iron and iron castings, made directly from molten iron. Forges, slitting mills and rolling mills were secondary producers, reheating and shaping pig iron into a wide variety of wrought iron products that blacksmiths, wheelwrights, and others could use. For example, in 1749 markerCharming Forge began producing wrought iron, and about 1780 added a slitting mill to make strips that could be fashioned into nails or other products. Some ironmasters, such as the owners of markerColeraine Forges in Huntingdon County, invested in both furnaces and forges, integrating the two steps in the production process.

exterior image of the entire complex.
Colebrookdale Furnace
Primary and secondary manufacturers sold their products in steadily expanding markets. Early ironmasters such as Rutter hoped to export iron to Britain, and Parliamentary passage of the Iron Act of 1750 stimulated some colonial exports to England. The domestic market, however, remained the main outlet. During the eighteenth century, ironmasters sold most of their products locally, due in part to expensive and slow transportation that hampered efforts to tap wider markets.

Ironmasters frequently asked the colonial assembly to improve roads and transportation to assist their trade. Petitioners from Lancaster County noted in 1736 that they suffered from a "want of Passable Roads" and appealed for a "Wagon Road from the Town of Lancaster to the Ironworks in Coventry" and at Reading Furnace. By the early nineteenth century, ironmasters began to transport more products farther afield, sending iron on horseback to Pittsburgh or down the Juniata and Susquehanna rivers to Baltimore.  Poor transportation deterred sales in wider markets, however, until the spread of canals and railroads after 1840.

A smouldering mound.
Completed charcoal pit–slow burn
Eager for transportation improvements and government action to protect markets, ironmasters were active in local and colony politics, and often held political offices. During the American Revolution most Pennsylvania ironmasters supported the patriot cause, in part because the war cut off competing British imports. They also supplied weapons and munitions to Continental forces.markerWarwick Furnace manufactured cannon and cannon balls, and most of the ironmasters in the Potts family supported the Revolution. In 1777 General Washington retreated to Warwick, had his troops seize all the leaden clock weights they could find in the village, and had the weights melted and cast into musket balls.

When British merchants dumped lower-priced iron products into the American market after the War of 1812, ironmasters sought federal tariff protection. Critics complained that protective tariffs would subsidize American manufacturers' higher costs and inferior technology, a point that tariff supporters conceded. Owners of secondary ironworks opposed protectionism because they wanted cheaper crude iron to process, including British imports. Congress sided with the protectionists, enacting tariffs between 1816 and 1832. Thereafter, Congress gradually reduced tariffs.

Image of a Charcoal kiln made of logs.
Charcoal kiln
As markets expanded, ironmasters built more charcoal furnaces rather than improve furnace technology to increase output or efficiency. Charcoal furnaces were inherently limited in size because loading iron ore into a larger furnace would crush the fragile charcoal fuel layered with the ore, smothering combustion and ore smelting. Pennsylvania ironmasters did have a potential alternative to charcoal furnaces after 1750; British iron manufacturers had developed furnaces fired with bituminous coke.

Pennsylvania ironmasters, however, did not try to adopt alternative technology until pioneers, such as the owners of markerKarthaus Furnace in 1838-1839, began using bituminous coal or coke. Pennsylvania ironmasters lagged behind the British in part because they expanded westward, with its abundant forests. Bituminous coal beds in western Pennsylvania were more remote from markets and inadequate transportation thwarted building bituminous coke furnaces near these coal beds before 1840. Pennsylvania ironmasters did adopt other British technological innovations, especially by replacing some forges with rolling mills. In 1816-1817 markerIsaac Meason opened one of the first rolling mills in Pennsylvania, producing wrought-iron products more quickly at lower cost.

This photo shows Lafayette Houck, the last of the Hopewell colliers, in a 1936 demonstration of charcoal-making at Hopewell Furnace. Mr. Houck is walking on the burning pile to find soft spots, which had to be dug out and filled in to maintain even burning.
Jumping the bit
Although some technological change came to the industry, in the early 1800s ironmaking still relied on charcoal furnaces. During the 1830s a handful of ironmasters also constructed the first anthracite coal furnaces, and by 1840 a few pioneers had tried experiments in making iron with bituminous coal or coke.  Only after 1840, however, did dramatic technological changes transform the industry. In 1845 Henry Robeson acquired a charcoal furnace, demolished it, and built an anthracite furnace named markerRobesonia Furnace, beginning a transition to another chapter in the industry's history.

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