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Determining the Facts

Reading 1: The Work at Hopewell Furnace

During the Colonial and early National periods of America's history, molded or cast-iron articles were the end products of a fairly simple process developed in the ancient world. The raw materials needed--iron ore, limestone, and hardwood forests for charcoal--were all available in the Hopewell area in Pennsylvania. Miners dug the ore from nearby open-pit mines and washed it in the stream. Limestone was cut from local quarries. Teamsters carried the ore and the limestone to the furnace. Charcoal making was an exacting and dirty job. More than 100 part-time woodcutters spent the winter cutting and splitting the hardwood needed to fuel the furnace. The wood was hauled to the coaling areas and made into charcoal during the spring, summer, and fall by skilled colliers. This was done by slowly charring it in "pits" under carefully controlled conditions. The coaling process was touchy, for enough heat had to be produced to expel the tar, moisture, and other substances from the wood without consuming the wood itself. Once the process was complete, the charcoal was raked out, cooled, and taken by wagon to the furnace where it was stored in the charcoal house.

With supplies of all the ingredients on hand, the founder, or furnace supervisor, directed the charging of the blast furnace--a tall, stone structure shaped like a flattened pyramid. An elevated walkway connected the furnace with storage areas on the furnace bank. Fillers rolled carts and wheelbarrows of charcoal, iron ore, and limestone over the walkway and dumped them into the top of the furnace. At approximately half-hour intervals, day and night, they repeated the process. A large wooden water wheel in a pit next to the furnace drove a pair of blowing tubs. These large wooden barrels fitted with pistons provided the blast of air that helped raise the temperature in the furnace to 2600-3000 degrees Fahrenheit, hot enough to convert iron ore into iron. In front of the furnace was the cast arch where the molten iron was periodically tapped. The furnace was allowed to cool down only when repairs were necessary or the supply of charcoal ran out. During the 1830s, it was usually "in blast" for approximately eleven and a half months a year.

Profits were greater for high quality iron that could be cast into saleable articles than for less-pure metal that required additional refining. The founder was responsible for controlling quality by regulating the precise balance of the ingredients and the blast of air. When he tapped the furnace, the founder decided whether the molten iron met the demanding standards for casting. If the flow contained too many impurities, the red-hot iron was run into beds dug in the sand floor of the cast house. Guttermen were responsible for preparing the beds and digging the channels into which the iron flowed. Because the pattern formed by the beds reminded early observers of a litter of nursing piglets, the resulting product was known as "pig iron." The pigs were shipped to forges for further processing.

If the molten iron was high quality, the founder rang the cast house bell, calling the skilled moulders to ladle the fiery liquid into their waiting sand molds. The founder's reputation, as well as his pay, was based on the percentage of high quality casting iron his furnace produced. Moulders were also paid according to the quality and quantity of their individual work. They received higher wages if they cast intricate and difficult designs. A mold was made by compacting a special sand around a wooden pattern in an enclosed box, or flask. It required great precision to keep stray grains of sand out of the pattern space. The cooled castings were taken from the cast house to the cleaning shed, where sand was brushed off and rough edges filed.

Hopewell workers manufactured a wide variety of pots, skillets, flat irons, wheels, sash weights, anvils, hammers, and grates, but the casting of iron stove plates was the mainstay of the operation through the 1840s. Many different types, including the famous "Franklin Stove," were produced in the casting house. Coal and wood-burning "Hopewell stoves" were well-known for their high quality, but some dealers furnished casting patterns which carried their own names rather than Hopewell's. Dealers usually completed the final assembly of the stoves. By 1844 Hopewell moulders had produced more than 65,000 stoves.

Questions for Reading 1

1. How was the furnace "charged" or fed?

2. Construct a flowchart showing the process of turning iron ore into finished products. Identify the workers responsible for each stage of the process. Why do you suppose there were so many different jobs?

3. Why do you think the furnace operated 24 hours a day whenever possible?

Reading 1 was compiled and adapted from the National Park Service's handbook, Hopewell Furnace: A Guide to Hopewell Furnace National Historic Site, Pennsylvania (Washington, D.C.: Division of Publications, National Park Service, Handbook 124, 1983).

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