CORNWALLIRON

FURNACEAdministered by the Pennsylvania Historical & Museum Commission

National Historic Mechanical Engineering Landmark

The American Society of Mechanical EngineersSusquehanna Section

Cornwall Iron FurnaceCornwall, Pennsylvania

June 8, 1985

CORNWALL IRON FURNACEIRON

“As they gather silver, and brass, and IRON,and lead, and tin, into the midst of the fur-nace, to blow the fire upon it, to melt it...”Ezek. 22:20.

The factors that gave rise to the IndustrialRevolution have been the subject of endlessspeculation by historians who have concludedvariously that these were simple and complex;the result of naturally unfolding events anddeliberate design; and furthermore, that if therewas a single root circumstance that made possi-ble this most momentous event in the progressof civilization it was the development of:sophisticated mining techniques; or the inven-tion and spread of the steam engine; or theemergence of the factory system of manufactur-ing; or any one of a number of others. Whileall of these occurrences indeed were importantcontributors to the Industrial Revolution, theywere underlain by a single crucial one uponwhich all the others were totally dependentand in the absence of which neither they nornearly any other element of our industrializedsociety could have evolved: the large-scale, ef-ficiently organized, wide-spread production ofthe ferrous metals. Without iron, cheaply andeasily available, the machinery of the IndustrialRevolution could not have existed. Without thesteel into which a certain portion of the ironwas converted the tools not only to producethe machinery but to work the mines and fieldsand to carry out literally every aspect of humanendeavor could not have been—could not be—possible. Iron and steel, plentiful and cheap,are the foundation upon which rests practicallyevery aspect of life, from the necessities offood, clothing, and shelter to everythingbeyond...

IRON IN THE COLONIESAlthough American colonial life depended

principally on wood for most of its mechanicalneeds, nearly every wooden structure, vehicle,mill, tool, boat, and domestic appliance re-quired some iron to join, band together, cut, orresist wear. For that reason the iron furnacemade an early appearance in the American col-onies. An even more compelling reason for thiswas exploitation by English companies of the

rich iron ore deposits and limitless forests thatprovided the fuel for smelting it into pig ironand forging the pig into bar iron, both productsshipped back to the mother country from theearliest period of settlement.

As early as 1619 a group of English investorsestablished a blast furnace at Falling Creek nearpresent-day Richmond, Virginia. But whatwould have been the first iron makingestablishment in America failed when theworkmen were massacred and the furnace wasdestroyed by Indians. The first successful ven-ture was in the Massachusetts Bay Colony atSaugus, near Lynn, north of Boston. The Ham-mersmith Ironworks, as it was known, went in-to operation in 1647. It was an integratedworks, its heart the blast furnace that producedpig iron and a line of cast-iron goods made bypouring the molten iron directly from the fur-nace into moulds. There also was a forge, inwhich a portion of the pig was reheated andworked under a tilt hammer to convert it intomalleable wrought-iron blooms which in turnwere rolled out and slit in the rolling mill toform that eminently useful item of commerce,nail rod. From that blacksmiths and other crafts-men produced an infinite variety of finishedproducts, from nails and builders’ hardware toplowshares and hoes to rifles and tools; themyriad iron objects so vital to life, both in thecolony and “at home.”

Most iron furnaces were called on during the AmericanRevolution to cast cannon, and Cornwall was no exception.Forty-two naval cannon were cast here, along with muchammunition. This cannon, once displayed on the lawn atthe ironmaster’s estate, has been returned to the Cast Housewhere it was made, probably in 1775.

This front plate for a five-plate stove is at-tributed to Cornwall Iron Furnace. Whilemany stove plates were cast here, the mainproduct of the furnace was always pig iron.

It was Pennsylvania, however, that eventuallybecame the prime center of iron production inthe colonies, a simple consequence of the hap-py combination within its borders of seeminglyinfinite deposits of the richest iron ores, endlesstimberlands, great deposits of limestone neededas a flux in the blast furnace, and plentifulwater power to drive both the bellows that pro-vided the blast air to the furnaces and the ham-mers and rolls that worked the pig iron intowrought-iron plate and bar. Finally—and nearlyas vital as the resources put in place by na-ture—Pennsylvania was blessed with a greatpool of ironmasters and workmen, mostly Ger-man, skilled in furnace and forge operation.

Despite both competition from British furnacesand forges, and a variety of restrictive measuresimposed by Britain on the colonial iron in-dustry in an effort to maintain its own interests,Pennsylvania's iron production flourished andgrew between the early years of the 18thcentury and the Revolutionary War. Iron wasfirst produced in the colony about 1720 at theColebrookdale Furnace in Berks County,perhaps named for the celebratedCoalbrookdale Furnace operated by the Darbysin Shropshire. By the time of CornwallFurnace’s establishment 22 years later therewere nearly a dozen furnaces in Pennsylvaniaand twice as many forges.

At the start of the Revolution the colonialiron industry actually was larger than that ofthe mother country, with 80 furnaces in nine ofthe colonies. There were more in Pennsylvaniathan any other colony—about twenty. Americaproduced about one-seventh of the world’s ironat the time, ranking third in production behindRussia and Sweden. Great Britain rankedfourth. It was this capacity that enabled thecolonies to manufacture ordnance andammunition in quantities sufficient to wage asuccessful war with England.

CORNWALL IRON FURNACE as it appeared circa 1860. Left toright: Cast House, Top of Furnace, Bridge House, and EngineHouse. In the background are visible the Charcoal House andMule Stables. Notice the railroad tracks terminating just outsidethe Cast House.

THE CORNWALL

FURNACE

From its inception Cornwall occupied aspecial position among Pennsylvania’s ironfurnaces. It owes its existance to the renownedCornwall Ore Banks a few miles south ofLebanon, a deposit of extraordinarily richmagnetite ore that until development of theLake Superior deposits was one of the mostvaluable iron-ore bodies in the U.S. It hadbeen discovered in 1734 by Peter Grubbduring a prospect. By 1737 he had purchasedsome 450 acres of the iron-rich land and in1742 built a blast furnace, naming the siteCornwall for the English county of mining fame

dwhere his father ha been born. Both mine andfurnace survive to the present day in testimonyto the vital role played by the American ironindustry during the 18th and 19th centuries inthe nation’s growth. The mine when in workwas the largest open-pit metaliferous mine inthe eastern U.S. It was exploited until 1973when the damage caused the previous year bythe flooding accompanying Hurricane Agnesdamaged the underground sections beyondeconomic restoration and it was abandoned bythe Bethlehem Steel Company, which hadoperated the mine since about 1883. Thedecision to quit the workings at that time wasreinforced by the fact that the ore was aboutplayed out in any case. With the cessation ofmining operations, and accordingly, pumping,came the inevitable flooding, leaving the minea pleasant, rock-bound lake.

The history of mine and furnace diverged in1883. Grubb operated the furnace only untilabout 1745 when he leased it to a company.He retained oversight of the ore banks,however, until his death in 1754 when itpassed to his sons Curtis and Peter. The entiresite was purchased from various Grubb heirsbetween 1785 and 1798 by Robert Coleman.Under the Coleman family’s stewardshipCornwall flourished during the centuryfollowing, going out of blast, finally, inFebruary, 1883.

At that point, the saga of the CornwallFurnace ceases to be one simply of asuccessful Pennsylvania blast furnace that hadbeen brought up-to-date in 1856, prosperedduring a heyday of some 25 years following,and then shut down in the face of competitionfrom the newer, larger, furnaces of the trans-Allegheny region that were based on the vastlymore efficient technology of the hot-blast andcoke fuel. The sequence was a common one.Even today the former iron-producing regionsof Pennsylvania and many of the other centralAtlantic states are dotted with the remains ofmany of these furnaces, in nearly all casesnothing more surviving than the stone furnacestack. The blowing and other machinery earlywas salvaged for either reuse or, morefrequently, for its value as scrap metal; thetimber roofs and walls of the buildings in timesuccumbed to the weather; and in more casesthan not even the durable furnace itself waslaid waste by local builders who took it as asource of ready-quarried-and-cut architecturalstone.

This photograph of the front of the furnace wastaken in 1898. Built in 1742. the furnace stackwas rebuilt in 1856 and enlarged from 20 to 28feet square at the base and from 11 to 21 feetsquare at the top. The hood over the arch is nowmissing, but the rake remains.

That Cornwall was spared the depredationsof weather and salvage is nothing less than amiracle of industrial archeology. That it hassurvived as the only 18th/19th-centuryAmerican blast furnace with its original fabricessentially intact is the result of nothing less,apparently, than family pride—if notsentiment—bolstered by the means that madedisposal of the land unnecessary. When thefurnace went out of blast in 1883, it remainedin the Coleman family which continued tooperate other, more modern furnaces in thearea. Clearly, the old site was kept and, mostimportant, maintained, as a monument toearlier generations of Coleman ironmasters. In1931 Margaret C. Buckingham, a great-granddaughter of Robert Coleman, deeded thefurance and its immediate ancillary structures,with their land, to the Commonwealth as ahistoric site, in the capable hands of which itsurvives today. In the visitors’ center andthroughout the site the technology ofironmaking in general and the saga of theCornwall mine and furnace in particular, areclearly laid out.

THE FURNACE’S

PHYSICAL HISTORY

Cornwall had two distinctly different lives.When constructed in the middle of the 18thcentury it seems from the scant survivingdescriptions to have been entirely typical of American iron furnaces of the period. It was asquat stone stack 20-feet square at the base and11 at the top, with a height of 31 feet. Theblast air was provided by a pair of wood-and-leather bellows nearly 21 feet long driven byan overshot water wheel taking its energy from

In the mid-19th century boilers were placed on top of the furnacestack to power the steam engine, which drove the blast equipment.The boilers are clearly seen in the brick structure atop the furnace.The furnace gases passed beneath them and were exhaustedthrough the chimney.

a small stream that traversed the site. Thefurnace was open at the top, and the measuredbatches of ore, charcoal fuel, and limestonewere charged in more or less continuouslysimply by being dumped into the opening bywheelbarrow. When the furnacemaster deter-mined that a sufficient quantity of molten ironhad been smelted from the boiling mass theblast was stopped and the simple clay dam atthe opening in the furnace bottom was partiallyremoved allowing the liquid slag to run off.The dam then was further lowered and theiron, pooled at the very bottom of the furnace,ran out into the moulds prepared in the floorof the casting house, to form the pigs and thepots, firebacks, or other, mainly domestic,products being cast at the moment. The pigswere about three feet long and weighedsomething less than 100 pounds, so sized thata man could lift and handle them. During theRevolutionary War cannon and shot were castat Cornwall as at many other colonial furnaces.

The average weekly production was about 20tons of iron although in one record year 1457tons were run out, a weekly average of some28 tons.

In 1856-57, after more than a century ofservice, the furnace was almost totally rebuilt.It is apparent that the only original fabric re-tained was the core of the furnace itself andthe masonry of the waterwheel pit. The furnacebuildings were rebuilt in stone and the furnacestrengthened and enlarged to its present size,although the capacity was not increased. Themajor functional change was replacement ofthe bellows by a vertical blast engine con-sisting of two wooden blowing cylinders or“tubs.” This was driven by a 20-horsepowerhorizontal steam engine that superceded thewaterwheel. The engine was built by the WestPoint Foundry of Cold Spring-on-Hudson, NewYork. The engine’s relatively high speed wasreduced to the lower speed at which the blow-ing engine operated by a large timber gear-wheel on its crankshaft, set in the formerwheel-pit, driven by a pinion and smallreduction gears.

From the blowing tubs, the blast wasdirected through the pipes (called tuyeres,)into the base of the furnace at three open-ings. The junction box allowed the founderto control the flow of air into the furnace.The tuyere arch at the rear of the furnace isseen at the lower left.

Steam for the engine was provided by a pairof plain cylindrical West Point boilers set inthe throat of the furnace, heated directly by theescaping furnace gases.

The result of this campaign of modernizationis the Cornwall Furnace we see today.Interestingly, the basic ironmaking processremained the same. Neither anthracite coal norcoke were introduced as the smelting fuelalthough both by then had found limited use insome furnaces of the region, and the “coldblast” was retained despite the fact that thesystem of heating the b blast air by heat ex-change with the furnace exhaust had been inuse for nearly a quarter of a century at anumber of American blast furnaces. It was a

process around which controversy still swirled,however Although generally it was concededthat use of the hot blast did increaseproduction efficiency, opinion among iron-masters and users was strongly divided on thequestion of the quality of the iron so produced.There was sufficient force of argument holdingthat a higher quality of both pig and wroughtiron resulted from the “cold-blast, charcoalprocess” that the adoption of the newermethods was far from immediate or universal.During the transition period from about 1860to 1890 the principal uses for charcoal ironwere for the production of specialty steels

employed in the tool and allied industries, andfor those elements of railroad rolling stockmost subject to impact and stress reversal: carwheels and axles, and locomotive driving-wheel tires. Improved methods of steelmaking—particularly the widespread use of theopen-hearth furnace—resulted in the readyavailablity of steels equal to those producedfrom charcoal iron and the eventual totaldemise of the old process.

Iron vessels cross the ocean;Iron engines give them motion;Iron needles northward veering;Iron tillers vessels steering;Iron pipes our gas delivers;Iron bridges span our rivers;Iron pens are used for writing;Iron ink our thoughts inditing;Iron stoves for cooking victuals;Iron ovens, pots and kettles;Iron horses draw our loads;Iron rails compose our roads;Iron anchors hold in sands;Iron bolts and rods and bands;Iron houses, iron walls;Iron cannon; iron balls;Iron axes, knives and chains;Iron augers, saws and planes;Iron globules in our blood;Iron particles in food;Iron lightning-rods on spires;Iron telegraphic wires;Iron hammers, nails and screwsIron everything we use!

An anonymous 19th-century poem intended to instillin children an appreciation of iron’s universality.

The large gear wheel which ran the blowing tubsand provided the cold air blast measures 76 feetin circumference.

OFFICE OF THE CORNWALL IRON COMPANYLIMITED stands at the entrance to the ironmaster’sestate, adjacent to the furnace site. This building alsoserved as an office for the estate and was built pro-bably by 1875.

The steam engine which drove the blast equipment was madeat the West Point Foundry at Cold Spring, New York. It wasinstalled around 1856. A 20 horse power, single cylinderengine, it has a fly wheel 9 feet in diameter. Steam wasgenerated by two boilers on top of the furnace stack, usingotherwise wasted heat.

THE OLD CORNWALL FURNACE.- GENERAL PLAN -

OF

·THE MACHINERY·(Reprinted from “An Engineer’s Miscellany”)

During its active existence and under themanagement of its many masters, the CornwallIron Furnace was a leading producer of pigiron as well as other products of the foundryfloor. Now that its commercial usefulness haslong since passed away and the quiescentsilence of old age is wrapped around its an-cient walls, few who now visit there can con-ceive it as it was in younger days, rampant androaring with flame and noise, one out of manythat have played their part in our iron age.

KEY TO THE FLOOR PLANOF THE CORNWALL IRONFURNACE AND FOUNDRY

A–The engine room.B–Cylinders of the blowing engine.C–The great gear wheel.D–Pinion and shaft.E–Regulator valve for the blast.F–Old water wheel pit.G–Boshes of the furnace.H–Damstone of the crucible.I–Slag dam.J–Pig iron mouldsK–Entrance to the foundry floor.L–Old entrance to the foundry.M–-Charging platform.N–Foreman’s room.O–Entrance to the weighing room.P–Stairway to men’s sleeping quarters.Q–Stairway down to the foundry floor.R–Watchman’s room.S–Steps up tp the engine room.T–Copper room, upper level.U–Copper room, lower level.V–Entrance to the blowing engine room.X–Exit from weighing room to stairs P.Y–Opening for the pitman, on early water

wheel.Z–Position of the early bellows.1 to 4–Furnace arches as originally designated.

FOR FURTHER READINGGreville Bathe, AN ENGINEER’S MISCELLANY.

Philadelphia: Patterson & White Co., 1938.Chapter VI, “The Old Cornwall Furnace”(pp. 61-77), is the most complete account ofCornwall and contains the most detaileddescription of its physical plant, withphotographs and measured drawings by theauthor (his plan is reproduced in thisbooklet). Long out o print but available infmany libraries.

Arthur Cecil Bining, PENNSYLVANIA IRONMANUFACTURING IN THE EIGHTEENTHCENTURY. Harrisburg: PennsylvaniaHistorical & Museum Commission, 1973.

W. K. V. Gale, IRON & STEEL. The IronbridgeGorge Museum Trust, 1979. 32pp., il-lustrated. A good general exposition on thehistorical development of the technology,principally in Great Britian. Available: IGMT,Ironbridge, Telford, Shropshire TF8 7AW,England.

W. David Lewis, IRON & STEEL IN AMERICA.Greenville: Eleutherian Mills-HagleyFoundation, 1976. 60pp., illustrated. The bestbrief survey of the industry in this country,describing not only its growth but also theprincipal processes for making iron and steel.Available: The Hagley Museum & Library,Box 3630, Greenville, Wilmington, DE19807.

James R, Mitchell, CORNWALL’S ROLE IN THEHISTORY Of AMERICAN MANUFACTUR-ING. Manuscript. Harrisburg: Penn-sylvania Historical & Museum Commission,1985.

Robert G. Peets, MINING HISTORY ATCORNWALL, PA. 1957; revised by H. O.Olsen, 1970. Bethlehem Mines Corporation,Cornwall, PA.

James M. Swank, HISTORY OF THEMANUFACTURE OF IRON IN ALL AGES,AND PARTICULARLY IN THE UNITEDSTATES FROM COLONIAL TIMES TO1891. Philadelphia: The American Iron &Steel Association, 1892 (2nd Edition). Whilethe references to Cornwall are sparce, this isregarded as still the best broad history of theindustry in America.

THE MAKING, SHAPING & TREATING OFSTEEL. Pittsburgh: United States Steel Co.,11th edition, 1985. This immensely in-formative and interesting work, publishedsince 1920 by USS, is principally an in-dustry textbook on all aspects of steel-making, from the mine to the finished IRON FURNACEproduct. Available: The Assn. of Iron &Steel Engineers, 3 Gateway Center,Pittsburgh, PA 15222.

ACKNOWLEDGEMENTSThe History and Heritage Committee of the

ASME’s Susquehanna Section gratefullyacknowledge the efforts of all who cooperated onthe designation of Cornwall Iron Furnace as aNational Historic Mechanical EngineeringLandmark.

The American Society ofMechanical Engineers

George Kotnick, PresidentRichard Hirsch, Vice-President Region IIIMichael R. C. Grandia, Chairman

History & Heritage Committee, Region IIIPaul F. Allmendinger, Executive Director

Jay Kohler, ChairmanDavid Kitlan, Chairman

Museum CommissionDr. Larry E. Tise, Executive DirectorJames R. Mitchell, Curator of Science,

John K. Robinson, PublicationsRichard Stratton, Historic Site Manager,

The ASME History & Heritage CommitteeDr. R. Carson Dalzell, ChairmanCurator Robert M. Vogel, SecretaryDr. Robert B. GaitherProf. Richard S. HartenbergDr. J. Paul HartmanProf. Enan F. C. SomerscalesCarron Garvin-Donohue, Staff Liaison

Richard Davidson, President

Special thanks to:

for compiling and editing this brochure, SteinerStudios, Annville, Pa. for their artwork andprinting expertise, and E. Johnson for his workon the ceremony program and invitations.

ENGINEERING LANDMARK

The ASME Susquehanna Section

History & Heritage Committee

Pennsylvania Historical &

Industry & Technology

Cornwall Iron Furnace

Cornwall Iron Furnace Associates

David KitlanJames R. MitchellJohn K. RobinsonRobert M. Vogel

NATIONAL HISTORIC MECHANICAL

WHEN ERECTED BY PETER GRUBB TO SMELT THERICH IRON ORE OF THE NEARBY CORNWALL OREBANKS, THIS STONE-BUILT BLAST FURNACE WASTYPICAL FOR ITS TIME, PRODUCING ABOUT 20 TONSOF PIG IRON AND CAST-IRON PRODUCT PER WEEK

A MAJOR RECONSTRUCTION IN 1856-57 PRODUC-ED IMPORTANT CHANGES. THE FURNACE ITSELFWAS ENLARGED; THE BLAST-AIR BELLOWS WEREREPLACED BY A OF PAIR OF WOODEN CYLINDER"BLOWING TUBS"; THE WATER WHEEL THAT HADP O W E R E D T H E M W A S R E P L A C E D B Y A20-HORSEPOWER STEAM ENGINE; AND A PAIR OFWASTE-HEAT BOILERS TO SUPPLY THE ENGINE WASINTO THE OPEN STACK OF THE FURNACE.

THE FURNACE WAS IN BLAST UNTIL 1883 IN THISFORM, AND SO REMAINS THE ONLY ONE OFAMERICA’S HUNDREDS OF 19TH-CENTURYCHARCOAL-FUELED BLAST FURNACES TO SURVIVEFULLY INTACT.

THE AMERICAN SOCIETY OF MECHANICALENGINEERS–1985

Over 80 National Historic Landmarks havebeen designated since the program beganin 1973. 14 International Landmarks and8 Regional Landmarks have also been recog-nized by the Society. Each represents a pro-gressive step in the evolution of mechanicalengineering, and each reflects its influence onsociety, whether it is of significance in itsimmediate locale, in the nation, or throughoutthe world. For more information about this andother programs sponsored by the ASME Historyand Heritage Committee please contact theASME Public Information Dept. at 345 E. 47thSt., New York, NY 10017. (212) 705-7740.

IMPORTANT DATES FORCORNWALL IRON FURNACE

1734-Peter Grubb buys land containing iron orewhich became the great Cornwall Ore Banks.

1739-Construction of Cornwall Furnace begins

1742-Furnace put in blast.

1785-98Cornwall Furnace and mine pass into thehands of Robert Coleman.

1856-57-Furnace rebuilt and enlarged; steam engineand blowing tubs installed.

1883-Furnace goes out of blast in February.

1932-Furnace site is donated to theCommonwealth by Margaret C. Buckingham.

1966-Cornwall Iron Furnace is designated aNational Historic Landmark by the UnitedStates Department of the Interior.

1976-Cornwall Iron Furnace is designated an ASMHistorical Landmark by the American Societyfor Metals.

1985-Cornwall Iron Furnace is designated aNational Historic Mechanical EngineeringLandmark by the American Society ofMechanical Engineers.

MakingSure Our Past

Has A Future

CORNWALL

ASSOCIATES, INC.

The ASME Susquehanna Section—Mechanical Engineering Landmarks to date:

Kaplan Turbine–York Haven Hydroelectric StationYork Haven, PennsylvaniaOctober 20,1980.

Worthington Pumping Engine–York Water CompanyYork, PennsylvaniaMay 7, 1982.

Electric Locomotive GG1 4800—Railroad Museum of PennsylvaniaStrasburg, PennsylvaniaApril 23, 1983 H106