Abstract Introduction Basic Geology Orgin of the Iron Industry George Washington
American Revolution Mining Dinosaurs Tales From Today The Future Acknowledgements

Appendix A.— Additional Notes on the Maryland Iron Industry

The Extent of the Maryland Iron Industry

The Council Proceedings Report to the British Commission of Trade and Plantations dated August 23, 1726, stated that there were eight furnaces and nine forges in operation in Maryland.1

Most sources agree that 15 to 20 furnaces and a like number of forges had been constructed in Maryland by the time of the Revolution. For purposes of comparison, it is interesting to note that in Pennsylvania, one of the major iron-producing colonies, 23 furnaces and 44 forges had been erected by the Revolution (although it is not known how many of these were still in operation.)2

The Maryland iron enterprises were:

Furnaces Forges
Principio Principio
Kingsbury Northeast
Lancanshire Baltimore/Gwynn's Falls
Baltimore/Gwynn's Falls Baltimore/Mount Royal
Baltimore/Charles Run Onion's Gunpowder No. 1
Onion's Gunpowder River Onion's Gunpowder No. 2
Snowden's Patuxent Snowden's Patuxent
Nottingham Ridgely's Long Calm No. 1
Ridgely's Northampton Ridgely's Long Calm No. 2
Dorsey's Elk-Ridge Unicorn
Dorsey's Curtis Creek Elk
Bush River Hockley
Antietam Cumberland
Mt. Etna Antietam/Potomac River
Mt. Etna/Leitersburg Rock Forge Furnace
Green Spring Hughes'/Antietam Creek
Catoctin Jacques'/Licking Creek
What did the Maryland Iron Works Produce?

The furnaces turned out pig iron and large cast objects. The forges produced bar iron, which is purer and more easily wrought product than pig iron. Because of the design of the furnaces, and the contemporary iron-making procedures, it is probably that the cast iron and the pig iron of the colonial era were far cruder materials than what we in the twentieth century have come to associate with the term "cast iron." The eighteenth century variety must have had a very high slag content, and without refining it in a forge, it could have been used only for rather rough castings.

Iron pigs were rectangular chunks, generally measuring 48"' 6"'3". One example marked "Patuxent Furnace, 1755"3 (recently recovered from the wreck of a French ship, Marqui de Malauze salvaged by the Canadian National Historic Sites Service) weighed 57 pounds. Pig iron had at least one "use" in that it was frequently carried as ballast in sailing ships.

Items cast directly at the furnace included firebacks — large flat pieces of iron which were placed at the rear of a fireplace to hold and reflect the heat; heavy implements for forges, including hammers and anvils; and stove plates. Other simple items were cast directly, utilizing molding sand and wood patterns. Such efforts resulted in what was generally termed "hollow ware" and included "pots, pans, skillets, sugar kettles, Dutch ovens . . ."4

Probably the largest items cast by Maryland furnaces were cannons. In the eighteenth century, cannon and shot were still produced by direct casting of iron. They had been the "principal product" of the English charcoal iron industry as far back as the mid-sixteenth century.5 It is widely rumored that cannon and ammunition for the Revolutionary War were produced at nearly every ironworks in Maryland. However, documentary evidence so far indicates that cannon casting took place only at Antietam Furnace, Elk-Ridge Furnace, Mt. Etna Furnace and the Baltimore Iron Works.

Most of the furnace production went into pigs which were then converted to bar iron, mostly for local use. ". . . The larger part of all the iron produced at the furnaces and forges was manufactured into tools, implements and wares, used chiefly by the colonists themselves."6 It was bar iron which was then wrought into the great variety of colonial necessities: nails, axes, shovels, scythes, hoes, chain, tire iron, hardware for other trades, including milling, shipbuilding, blacksmithing, coopering, lumbering, domestic fittings, including hinges, bolts, straps, and cooking gear.

1 Quoted in John H. Alexander, Report on the Manufacture of Iron (Annapolis: William McNeir, 1840), p. 70.

2 Bining, [Arthur C., 1938,] Pennsylvania [Iron Manufactureres in the Eighteenth Century: Pennsylvania Historical Commission, Harrisburg], pp. 187-89.

3 The Iron Act of 1750 required that pigs be stamped with the date of manufacture and the name of the furnace. See Bining, Pennsylvania, pp. 154-5.

4 Bining, Pennsylvania, p. 80.

5 Ashton, Iron and Steel, p. 7.

6 Bining, Pennsylvania, p. 80.

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