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A Blast From The Past: Cornwall Iron Furnace

By Sharon Hernes Silverman
This article originally appeared in Pennsylvania Heritage Magazine
Volume XXIV, Number 2 - Spring 1998

Today the great silent wooden waterwheel at Cornwall Furnace radiates a serene, abstract beauty.  It once powered twenty-foot-long bellows that supplied intense heat required for smelting. Driving on narrow sinuous back roads through lush, verdant forests-just a half dozen miles north of the busy Pennsylvania Turnpike-unsuspecting travelers can't help being struck by an odd-looking complex of Gothic Revival-style buildings and structures. This place, this curious collection of buildings, both large and small, appears to have been literally plucked from a far away and long ago countryside of, perhaps, England, or Scotland, maybe Wales, even Ireland. As they continue deeper into the heartland of what was once one of America's vast iron plantations, travelers begin to notice churches, homes even an entire village, built in the same picturesque style. Their journey takes them not only farther into the bucolic countryside of Lebanon County, but back through time when this very place thundered with a deafening frenzy that helped build America. Today, this place, Cornwall Iron Furnace, is quiet and peaceful. Its stack no longer belches sooty, black smoke, and its mammoth open mining pit has filled with water. The scene is mesmerizing, sometimes haunting.

Years ago, this was a small, self-contained village-nearly feudal in its hierarchy of ironmaster and his workers. Amid the gently countryside of the Susquehanna Valley, with its iron-laden, dense sprawling forest, and abundant rivers and streams, it was perfectly situated to become one of the country's earliest and most productive ironworks. Cornwall Iron Furnace holds an intriguing story that spans two centuries and whose power and effect are not diminished even today. Behind its main building-with piercing lancet windows, arching doorways, vaulted ceilings, and thick wooden beams-and the soft russet hues of its sandstone walls, Cornwall Iron Furnace stands fully preserved today as a stunning example of one of Pennsylvania's oldest and proudest industries. It is the only place in the western hemisphere where a curious traveler can see intact structures of an early charcoal-burning iron blast furnace in its original plantation surroundings.

Cornwall Iron FurnaceA visit to Cornwall today offers a way to experience what life was like in a well-planned industrial complex, a vital part of the iron industry that formed the economic backbone of Lebanon County and laid the foundation for the development of the United States as an industrial giant. It also provides an introduction to the people who formed the community, from the ironmasters and their families at the upper strata of the social structure, to the skilled workers and laborers and their kin, and the lower reaches who supported this system.

A leading producer of iron for Pennsylvania from 1742 to the end of the nineteenth century, the furnace continued in blast until shut down in 1883. Richard B. Strattan, historic site administrator at Cornwall Iron Furnace, says the well-preserved site is something of "a time machine," making it easy to imagine the furnace operation of the past. "You could see hot gases coming out of the top. With sulfur in ore there were terrible smells. And noises-you could hear the air blasting in the furnace for miles!
Think of the woodcutting. This furnace used an entire acre of wood every day for making charcoal."

The agricultural-based colonial era economy needed iron that could be fashioned into implements, tools, nails, and weapons. Although Great Britain's imperial policy frowned on manufacturing in the colonies, necessity protected early American metallurgy. The near exhaustion of forests in England had forced ironmasters to adopt the more complicated production of coke for fueling furnaces by the late eighteenth century. Most of its pig iron and bar iron had to be imported.

Wood, taken from timber stands on three hundred acres of Peter Grubb acquired in 1734, was split, brought to dry, level sites, and then made into charcoal by slowly roasting it in large hearths, or In 1734, Peter Grubb acquired three hundred acres about five miles south of present-day Lebanon and found that its magnetite-rich iron ore was surrounded by the other elements needed for an iron plantation: flowing water to run bellows, timber for charcoal, and limestone to add flux to the iron smelting furnace. The magnetite ore not only was lower in oxide content that other ores, but at Cornwall it lay atop and only slightly below the earth's surface, another advantage for Grubb. America's early iron centers were usually located away from heavily cleared regions, and the need to house groups of workers created isolated plantation communities. Grubb began by building a bloomery, in 1737, to test the value of his ore. Bloomeries belonged to an older technology which blast furnaces were gradually replacing. Basically enlarged blacksmiths' hearths, the blooms-lumps of pasty iron-the bloomeries produced were an impure iron because the process only partially melted the iron ore. The blooms were than hammered to remove carbon, producing a wrought iron of inferior strength.

Replacing this with the superior technology of a thirty-foot high blast furnace in 1742, Peter Grubb turned out a highly carbonized but brittle iron. It was about this time he named the operation Cornwall for the county in England from which his family had emigrated.

Some methods of making charcoal, as in this 1929 photograph, called for covering the wood with pine needles and damp soil to prevent the high heat from consuming the wood.Producing greater heat than any bloomery could, the furnace rendered molten iron from the ore. Impurities, including "sinter" (or cinders), silicates, and phosphorous were separated as slag and discarded, and a highly carbonized iron was drained into shaped areas of two types to cool and harden. Long depressions in sand produced irregular bars, called "pigs" because their formations resembled piglets nursing from a mother sow. If not made into pig iron, the molten iron was drained into forms for rigid objects such as cooking devices, stoves, and eventually cannon barrels. This was cast iron. Both cast iron and pig iron had high carbon content, but the pig iron was taken to iron forging facilities where heating and pounding turned it into quality wrought iron.

The blast which gave the technology its name was air forced in under pressure from leather bellows driven by a water wheel turned by the Furnace Creek. An arched recess in the side of the furnace contained the blast pipe, called the tuyere, which conducted the forced air into the furnace's fire. The blasts produced spurts of intense heat necessary to melt the ore. Temperatures rose to levels between 2650 and 3000 degrees Fahrenheit. In the crucible, or hearth at the bottom of the furnace, iron oxide in the ore was reduced as oxygen combined with the ascending carbon monoxide gas from the burning charcoal, generating, as end products, iron and carbon dioxide.

The furnace, built of native sandstone, stood on the side of a hill whose inclined path made it easy to raise charcoal, iron ore, and limestone flux the thirty feet to the top of the stack. A find grade of sandstone lined the stack, and clay or mortar filled the space between it and the outer stone.

Downward from the square opening at the top, the stack widened until it reached its center, the "bosh," which was nine feet wide. Below that, the furnace tapered inward to four feet at the hearth or crucible. This shape maximized the concentration of heat and the lower inward sloped walls were necessary to support part of the working mixture. Without this slope, the mix would have been so concentrated that the blast could not have passed through the mixture. Adjacent to the hearth was the casting house or shed in which both the cast objects and the iron bars were made.

Workers pose atop a charcoal pit, where conditions were carefully controlled and watched to insure the complete charring of wood, a process that took about two weeks.Control was exercised by the founder, stationed at the top of the stack, called the tunnelhead. He determined the proportion of charcoal, ore, and limestone flux that made up the batch to be dropped in. These inserted materials were called the charge. He made his mix by deciding how many filled baskets of each of the three components to include, rather than precisely measuring or weighting the items. The heat was a variable of the quantity of charcoal in the charge. If the founder perceived that the furnace flames were dark, the furnace was not hot enough; if bright and smoky, there might be excess limestone or not enough ore.

The making of mass quantities of charcoal to fire the furnace was an industry in itself. Split wood-preferable hickory, chestnut, black oak, or white oak-was hauled to dry, level sits sheltered from the wind, free from stones but not loamy or sandy. The wood was made into charcoal by slowly roasting it in thirty-to forty-foot diameter hearths or "pits" under carefully controlled conditions. The collier stacked cordwood around a central chimney. This mound was then covered with leaves and dirt and set on fire at the center. Each pit took twenty-five to fifty cords. A collier carefully tended the smoldering wood around the clock for ten to fourteen days until it was completely charred. Enough heat had to be produced to expel tar, moisture, and other substances from the wood without consuming the wood itself. The collier located soft spots by jumping of the mound, then dug them out and refilled them. To avoid the possibility of the charcoal getting wet and becoming unusable, wood was usually cut and stored in the winter, and not charred until just before it was needed.

Cornwall Iron Furnace was one of many ironworks constructed in Pennsylvania during a sixty-year period, form 1716-1776. At least twenty-one blast furnaces, forty-five forges, four bloomeries, six steel furnaces, three slitting mills, two plate mills, and one wire mill operated in the colony. The production of these mills and steel furnaces, irked English iron- and steelmakers because the colonial American iron industry accounted for about one-seventh of the world's output of pig iron, wrought iron, and castings. By the early eighteenth century, England's metal industry depended largely on bar and pig iron from Sweden, mostly because English forests had been depleted by decades of charcoal production. When dependence of the Swedish became burdensome, Parliament passed the Iron Act of 1750 to encourage importation into England of colonial pig iron and unfinished bar iron. The act also forbade the establishment any new colonial sitting mills, plate mills, or steel producing furnaces. Shipment of pig and bar iron across the Atlantic increased and, in fact, restrictions on the advanced iron products made in America were largely ignored, so that the Iron Act was only a minor factor among discontented colonists by the time of the American Revolution. Gothic Revival-style lancet windows and arches distinguish Cornwall Iron Furnace's main buildings.  Interior features include thick wooden beams and vaulted ceilings.

A sizeable labor force was required to keep the iron plantation running smoothly. Thirty to sixty people worked twelve-hour shifts at the furnace. In addition, the iron works employed a company clerk, teamsters, woodcutters, colliers (charcoal-makers), farmers, and household servants. "From most account, the workers were well-treated," says Strattan. "However, there was a huge gap between the workers and the owners." At the opposite end of the social and economic spectrum from the laborers was the owner, or ironmaster, ruler of a self-contained head of a community not unlike an Old World feudal barony. He and his family inhabited a mansion of vast acreage, and styled their way of life much like that of English gentry.

Because this first stage of iron-both pig and cast-is brittle, it was best suited for products that would not be subject to continuous stress or repeated impact. Carbon-rich cast iron was, however, suitable for heavy containers and objects made to withstand fire. Reliable cannon barrels were also made of cast iron. For items that required tougher iron, bars of pig iron were transported to a forge where they were further refined by heating and pounding. This stronger iron, known as "wrought iron," could be forged into shapes, such as horseshoes, or sent through a rolling or slitting mill to make plates, bars, or nail rods.

What an impressive-though not necessarily pretty-sight the furnace was when "in blast," which was twenty-four hours a day, seven days a week, unless repairs were needed. From the huge barn, buggies full of charcoal rumbled beneath the protective roof of the connecting shed to the furnace building, then back for another load. At the same time, creaking ore wagons drawn by teams of horses or mules lugged iron ore up the road ascending to the furnace. Loads of the components were carried across a horizontal walkway to the open top of the towering furnace stack, where they were dumped.

A large wooden waterwheel drove a twenty-foot-long bellows, furnishing the air blast necessary to intensify the heat to smelting temperatures. Eighteenth-century furnaces came to be termed cold-blast to distinguish them from a nineteenth-century improvement in which escaping inflammable gases were turned around to pre-heat the air blast before it passed through the tuyeres. During the nineteenth-century, some furnaces were hot-blast while some were the older cold-blast type. A charcoal wagon placed aside in the Cornwall furnace building, which stands fully preserved today as a symbol of one of Pennsylvania's oldest and proudest industries.

Eighteen to twenty charges a day resulted in output of twenty-four tons of iron each week. At the base of the furnace, guttermen raked the sand and dug channels for the molten pig iron, then stacked the bars outside. Working conditions were brutal; temperatures inside the casting house could reach as high as 160 degrees Fahrenheit.

Three classifications of workers were employed at the Cornwall Iron Furnace: free labor, indentured servants, and slaves. While slaves were employed, there was opposition to their importation. Throughout the eighteenth century acts were passed restricting slave traffic, culminating in the 1780 act for the gradual abolition of slavery, in which Pennsylvania prohibited the importation of slaves. The hiring of indentured servants proved problematic. Most of the redemptioners were unskilled workers from Germany, England, and Ireland. Despite their indenture, these servants ran away with alarming frequency; perhaps for that reason they were hired in small numbers.

Curttis and Peter Grubb, who had inherited Cornwall Iron Furnace from their father, Peter Grubb Sr., upon his death in 1754, supported the American Revolution. Their furnace cast cannon, shot, and ironware for the Continental cause. Labor was in such short supply that the Grubbs and other ironmasters received permission to use Hessian prisoners of war as workers.

Robert Coleman, who rose from the ranks and took over Cornwall Iron Furnace and much of the mine from the Grubbs by 1798, was the first of four generations of Colemans who would dominate Pennsylvania's ironmaking industry. Coleman arrived in Philadelphia from Ireland in 1764. In two years he rose from a clerkship in a prothonotary's office to a position as bookkeeper for Curttis and Peter Grubb, during which he leaned about the business and technology of ironmaking. He next served as a clerk for ironmaster James Old at Quittapahilla Forge in Lebanon County. He married Old's daughter Ann in 1773, the same year he leased Salford Forge near Norristown, Montgomery County.

Diagram of a stack: built from native sandstone, it widened from its square opening at the top to nine feet wide at the center, tapering to four feet at the hearth, or crucible.Iron was in great demand by the time of the American Revolution, which provided enormous opportunity for Robert Coleman. He leased Elizabeth Furnace, at which he manufactured cannonballs and shot. He used his wartime profits to acquire a two-thirds share of Elizabeth Furnace, purchased Speedwell Forge, and became part owner of Cornwall and the Upper and Lower Hopewell Forges (different than Hopewell Furnace in Berks County). In 1791, he built Colebrook Furnace, and three years later purchased the balance of Elizabeth Furnace, then half of Henry Grubb's share of Cornwall and the Hopewells, all of Curttis Grubb's share of the Cornwall Ore Banks and the Cornwall Iron Furnace, and all of the Mt. Hope Furnace. His insatiable appetite for acquisitions gave him more than eighty percent of the Cornwall properties. And his ferocious ambition earned him distinction as the Keystone State's first millionaire.

In 1809, the prosperous Coleman and his family moved to Lancaster. A daughter and a son died in the following two years; two other daughters married, leaving only Ann Caroline and Sarah at home with their parents. But before long, tragedy would strike these two young women.

An unmarried 22-year-old, the dark-haired Ann Caroline began seeing James Buchanan sometime during 1818, after being introduced to him by her cousin Eliza Jacobs, who was being courted by Buchanan's employer Molton Rogers. Buchanan was no stranger to Ann: she frequently observed the tall, handsome man pass by her window on his way to and from the courthouse. Soon they became engaged, but Ann's parents were not happy. Especially troubling to Robert Coleman was Buchanan's checkered record at Dickinson College, from which he had been dismissed, then reinstated, and at which he had twice come under faculty discipline. Coleman was proud of his wealth and wary of anyone he believed might have had designs on it.

Buchanan's long hours at work increasingly kept him away from Ann, and she too grew suspicious of his motives. Returning from Philadelphia, Buchanan tarried at the home of an acquaintance, in the company of the man's sister-in-law, before continuing on to see Ann. Upon hearing of his dalliance, e en though it may have been purely innocent, she immediately broke their engagement.

The huge casting arch dominates the furnace building at Cornwall, where cannon, shot, and iron were manufactured for the American cause during the Revolutionary War.  Many ironworks were constructed in Pennsylvania from 1716 to 1776 - much to the displeasure of England.Ann Caroline was sent to Philadelphia to help her recover from the depression she suffered after this affair, but the opposite occurred. Just after midnight on December 9, 1819, Ann Caroline was found dead. The official cause of death was noted as "hysterics," but most residents of Lancaster suspected suicide.

Buchanan was devastated. Ann Caroline's father rebuffed him refusing his request to attend the funeral, and he became the subject or much conversation and conjecture. Some believe Buchanan never married because of his failed relationship with Ann Caroline Coleman-her portrait still hangs at Wheatland, his residence in Lancaster County (see "The Political Ascent of James Buchanan" by Kurt d. Zwikl in the Spring 1991 issue).

Ann Caroline's sister Sarah also met a sad end. Smitten with William Augustus Muhlenberg, co-rector of St. James Episcopal Church in Lancaster, she found herself inextricably caught in the middle of a bitter dispute between the Reverend Muhlenberg and her father over evening worship services. After he father's death in August 1825, Sarah hoped to marry Muhlenberg, but Robert Coleman's power reached beyond the grave: his will had granted his sons Edward and James the right of approval of their sister's future husband. Edward the eldest, disliked Muhlenberg, and Sarah fled to Philadelphia where she killed herself.

The following generation of Colemans saw their fortune swell once again. George Dawson Coleman, son of James, owned a one-sixth share of the Cornwall Ore Banks. He experimented with innovative anthracite furnaces, invested in railroads, and built houses, a school, and a church for his employees. He was a much-loved member of the community and a tireless public servant. He was elected several times to the state legislature. On his death in 1878, the entire region mourned his passing. Another picture of the casting arch.

Although anthracite blast furnaces and other technical innovations brought about increasing competition by the 1840's, Cornwall Iron Furnace carried on. Over the years, improvements were made to the operation in efforts to keep it competitive with newer furnaces. In the late eighteenth century, the large, inefficient bellows had been replaced with two "blowing tub," cylindrical casks in which air was alternately compressed by pistons driven by the wheel, providing a more uniform blast. Water wheel power was succeeded by a steam engine in 1841. The furnace was remodeled in the 1850s by the rebuilding of the stack. In 1848, the Colemans turned over the management of the furnace to young West Point graduate, John Fulton Reynolds, who managed it until the Civil War broke out. Reynolds resigned from the operation to accept a general's commission in the Union Army. He died heroically when serving as the first Union commander at the Battle of Gettysburg.

Iron was in much demand during wartime, but it was not until 1864 that ironmasters in the North began to realize distinct profits. Fluctuations in the tariff statues had so much to do with the business vitality of America's furnaces, as competition with British pig iron and bar iron was intense. In its last decade of operation, Cornwall Furnace operated at a loss.

A telling symbol of the sprawling iron plantation's self sufficiency is the butchery.  The structure repeats some of the architectural elements of the larger buildings.The Bessemer and open-hearth processes of steel production, the use of anthracite, the widespread use of code, the discovery of Lake Superior iron ore deposits, and the urbanization of factories (to locate them near rail terminals) weighed heavily against the Colemans' old-fashioned system. In 1879, Robert Habersham Coleman, having completed his education at Trinity College in Hartford, Connecticut, and recently married, took over the managing control of the family's holdings. The tragic death of his young bride, Lillie, soon followed, and by 1881 he was fully immersed in details of business. His worth was then about seven million dollars; 1889 the estimate had surged to thirty million. He was opening a series of technically advanced anthracite furnaces, and he shut down Cornwall Furnace forever on February 11, 1883.

Robert Habersham Coleman's glorious decade followed. He modernized production and marketing on the family's thousands of farm acres in Lancaster, Lebanon, and York Counties. He obtained controlling interest in a bank in Lebanon and opened a rolling mill. In 1889, he created the magical summer colony of Mount Gretna (see "The Magic of Mount Gretna: An Interview with Jack Bitner" by Diane B. Reed in the Spring 1992 edition), a pleasure stop on his Cornwall and Lebanon Railroad. He built houses, schools, and a church for his workers and their families. By his second wife, Edith Johnstone of Baltimore, he had five children. In Florida, he acquired a railroad construction company and a fifty-mile stretch of the Jacksonville to Palatka Railroad. His beneficence knew no bounds; he generously supported his alma mater and his college fraternity, as well as St. James Episcopal Church in Lancaster where his family had long been communicants. But the seemingly impossible happened. The unsinkable Coleman empire began to tremble.

Early photograph, circa 1865, of Cornwall Iron Furnace, which helped from the economic backbone of Lebanon County.  An improvement over earlier bloomeries, the furnace rendered molten iron from the ore.Robert Habersham Coleman lost a lawsuit against the Grubb family, which had been taking ore without compensating the Colemans, In 1891, he lost another suit, this one to the Pennsylvania Trust Company. The award: a staggering one-and-a-half million dollars. If financial reverse were not enough, he also realized that he was tubercular. When stock market investors panicked over low gold reserves in 1893, the Coleman fortune vanished. At the age of thirty-seven, Robert Habersham Coleman and his family left Lebanon County for Saranac Lake in New York's Adinondacks, where he lived as a recluse until he died in 1930 (see "A Dynasty Tumbles" by Jan Margut Habecker in the Winter 1875 edition). The Cornwall iron ore banks, because of the location of ore close to the surface were still being mined by succeeding owners until the 1960s.

Today, the rich legacy of Cornwall's illustrious career is evident to visitors who tour the spectacularly preserved site, donated by Margaret Coleman Freeman Buckingham to the Commonwealth of Pennsylvania in 1932. As they drive through quaint Minersvillage, they can't help but admire picturesque company-built stone houses lining the street. From the Cornwall Iron Furnace grounds, they can see the Coleman family's opulent mansion (now a private retirement center), one decorated with exquisite furniture from Napoleon's palace and ancient relics from Pompeii. Then begins the tour of the charcoal barn and the furnace building. As the giant wooden wheel turns and the machinery hums, visitors can literally feel the power of American industry at the place where it all began.

Designated a National Historic Landmark, Cornwall Iron Furnace is administered by the Pennsylvania Historical and Museum Commission. Days and hours of operation are subject to change; please call ahead at (717) 272-9711. Guides conduct tours until an hour before closing. A Visitors’ Center located in the old charcoal barn contains exhibits and a museum shop. There is an admission fee.

For information write: Cornwall Iron Furnace, P. O. Box 251, Cornwall, Pennsylvania 17016; or telephone (717) 272-9711. Persons with disabilities who need special assistance or accommodation should telephone the historic site in advance of their visit to discuss their needs. Persons who are deaf, hard of hearing, or speech impaired who wish to contact a hearing person via Text Telephone may use the PA Relay Center at (800) 654-5984.

The iron plantation featured a self-contained village with a sizable labor force that included ironworkers, woodcutters, colliers, farmers, and household servants.  It was nearly feudal in the relationship between ironmaster and workers.Created in 1813 out of parts of Dauphin and Lancaster Counties, Lebanon County was settled by Germans who immigrated in large numbers from the Palatinate. The Lebanon County Historical Society, Lebanon, founded in 1898, collects, preserves, and exhibits objects and artifacts chronicling the county's history. The Union Canal Tunnel Park, administered by the society, is a National Historic Civil Engineering Landmark, and is the oldest existing transportation tunnel in the United States. The Gallery at Lebanon Valley College, Annville, encourages regional artists through performance, exhibition, and acquisition of their work. Well-kept streets and company-built stone houses were hallmarks of the village at Cornwall.  From the grounds, workers could see the Coleman family mansion, now a retirement center.

Information about these and other attractions in the county is available by writing: Lebanon Valley Tourism Promotion Agency, 80 Rocherty Road, Lebanon, PA 17042. Phone (717) 273-3670.



Travel writer Sharon Hernes Silverman of West Chester, Chester County, is a regular contributor to Pennsylvania Heritage. Her most recent feature, "Step Back in Time: Graeme Park, Colonial Country Estate,” appeared in the Winter 1998 issue.

The author thanks Richard B. Strattan, historic site administrator, and guide Will Perry of Cornwall Iron Furnace.


For Further Reading

Bining, Arthur Cecil. Pennsylvania Iron Manufacture in the Eighteenth Century. Harrisburg, Pennsylvania Historical and Museum Commission, 1979.

Bomberger, Bruce, and William Sisson. Made in Pennsylvania: An Overview of the Major Historical Industries of the Commonwealth. Harrisburg: Pennsylvania Historical and Museum Commission, 1991.

Gordon, Robert B. American Iron, 1607-1900. Baltimore: The Johns Hopkins University Press, 1996.

Klein, Philip S. President James Buchanan: A Biography. University Park: The Pennsylvania State University Press, 1962.

Lewis, W. David, and Walter Edward Hugins. Hopewell Furnace: Official National Handbook. Washington, D.C.: U.S. Department of the Interior, 1983.

Miller, Frederic K. The Rise of an Iron Community: An Economic History of Lebanon County, Pennsylvania from 1740 to 1865. Lebanon: Lebanon County Historical Society, 1950

Oblinger, Carl. Cornwall: The People and Culture of an Industrial Camelot, 1890-1980. Harrisburg: Pennsylvania Historical and Museum Commission, 1984.