Features appear in each issue of Pennsylvania Heritage showcasing a variety of subjects from various periods and geographic locations in Pennsylvania.

As it stands today, the ruin of Lock Ridge Furnace at Alburtis, in Lehigh County, looks more akin to a misplaced Norman fortress than a nine­teenth century anthracite iron furnace. The partially re­stored walls, reinforced by heavy metal bolts, give the venerable Pennsylvania structure a false touch of the medieval.

The productive history of the anthracite iron furnaces began in December 1866 when the Lock Ridge Iron Com­pany was chartered to build two furnaces in southwestern Lehigh County. Three technological changes in the develop­ment of the blast furnace in the mid-1800s created a brief halcyon period for Lehigh Valley iron production. By the time the first Lock Ridge furnace was fired, anthracite coal had proven itself a superior substitute for the more inferior charcoal. The use of hot-blasting, pioneered by Pennsyl­vania Welshman David Thomas, replaced cold air drafts. Hotter furnace temperatures were provided by the ignition of the coal.

The final mid-nineteenth century technological change which ultimately shifted the focus of iron production to the Lehigh Valley was the introduction of the steam engine, replacing the mill race which originally provided cold water for cold air drafts. With the addition of steam technology, larger furnaces, like the ones at Alburtis, were built near Allentown. Finally, greater amounts of pig iron were produced for commercial markets.

In May 1867, two months after the first anthracite fur­nace was fired at Alburtis, the Thomas Iron Co. of Cata­sauqua bought out the entire capital stock of the Lock Ridge Co. in the village of Lock Ridge (now Alburtis). The Thomas Iron Co., founded by the inventive immigrant ironman David Thomas, formed the axis of a nationally competitive iron industry concentrated in the Lehigh River valley. The company flourished during the closing years of the 1800s and through the early years of the present century.

Even before the construction of Lock Ridge Furnace, the Lehigh Valley area was the scene of a developing iron industry. Abundant with the raw materials needed for the production of iron, the valley offered close proximity to anthracite coal and iron ore (both low grade limonite iron ore and the higher grade ore known as magnetite were available from nearby deposits). Dolomite limestone was used as “flux” in the furnaces and was abundant underfoot, forming the rocky mantle of the Lehigh Valley’s floor. Early settlers were aware of the stone’s applications and crushed it as a lime fertilizer for many years. In addition to ample supplies of natural resources, the area benefited from a canal system to transport the pigs to large metropolitan markets such as Philadelphia, New York City and Balti­more, making the area a seed bed for a new industry based on iron.

A blast furnace at Mauch Chunk (now Jim Thorpe) in Carbon County predated the Lock Ridge Furnace, oper­ating as early as 1838. The owners of that prototype an­thracite iron furnace were able to produce as much as two tons of pig iron a day for a period of three months. The furnace, however, eventually faced financial ruin and the infant anthracite iron industry suffered a false start, nearly thirty miles from the Lehigh Valley. It was not until the Lehigh Crane Iron Co. contacted David Thomas, a Welsh ironworker turned engineer and inventor, that history was finally made along the banks of the Lehigh River and its tributaries.

In his native Wales. Thomas had experimented with hard coal or “stone coal” as anthracite was called. Born in November 1794 in the County of Clamorgan, South Wales, the son of a Presbyterian church warden, Thomas is often considered the “Father of the Anthracite Iron Industry” by his admirers despite the earlier attempts of others to establish the industry. Anthracite was immediately seen as advantageous for the smelting of iron by Thomas because it produced little smoke when burned. He took advantage of the sole bed of Welsh anthracite near Swansea in South Wales, and at the ripe age of twenty-three, was made super­intendent of the Yniscedwyn iron Works there.

It was the Lehigh Crane Co., however, that fully realized the engineering and managerial genius of young David Thomas. Visited in Wales by a Lehigh Crane representative, Thomas was enticed by the Pennsylvania company to pace out a site for an anthracite iron furnace as well as to superintend its construction and operation. The site was Crane­ville (Catasauqua) on the Lehigh above Allentown. Thomas finally relented and left Wales for Pennsylvania.

By 1840, with family securely settled in the Lehigh Valley, Thomas watched Craneville blossom as a busy company town around Lehigh Crane’s new blast furnace. But to Thomas’s consternation (as well as his employers), the labor of two years was wiped out in a flash flood of the Lehigh in 1841. Until the flood, 1,080 tons of iron had been smelted at Craneville and production was at an all time high for the new industry. As much as fifty tons of pig iron poured out of the Craneville plant daily. This was an admirable start for a fledgling Pennsylvania industry and its new technology.

The Craneville furnaces were rebuilt in 1841-42, but little is recorded of Thomas’s activities following the Crane­ville years. It is known, however, that additional good fortune came his way once again in 1854. Thomas achieved his greatest success when he and several Lehigh Valley business associates, founded their own iron company in Easton, along the Delaware River.

On the blustery night of February 14, 1854, eighteen men filed into Mrs. White’s Tavern on Center Square, in Easton. The grog was warm, and the atmosphere and cheer were right for the organization of the Thomas Iron Company. The small cadre of businessmen and admirers of Thomas’s past innovations in pig-iron production, voiced their support for the development of additional blast fur­naces along the Lehigh. Hokendauqua, they agreed, would be the initial site.

The new company fixed its capitaJ at $200,000 and a committee of seven was appointed to survey and purchase land for the construction of a furnace. By the next meeting in Mrs. White’s Tavern on February 28, officers were elected and David Thomas’s iron empire was off to an enthusiastic start. Thomas himself would remain as direc­tor, and later vice president, until his death in June 1882. The Welshman at first continued as well with the Lehigh Crane Co. until 1860 when he finally severed ties with that company to fully develop his own endeavor.

David Thomas, and later his son Samuel Thomas, ran a great number of highly profitable blast furnaces at Hoken­dauqua, Island Park near Glendon and Hellertown south of Bethlehem. Between 1840 and 1865, twenty blast furnaces sprang up along the Lehigh River within a five-mile radius of each other. The East’s iron production was most ener­getic here, and the construction of railroads, locomotive wheels, axles, frames and rails utilized pig iron from these and other Pennsylvania furnaces.

For the Welsh engineer now turned businessman, techni­cal matters were as much a part of the Thomas Iron opera­tion as the overseeing of outside purchases and transfers of stock. He took personal interest in the construction of new equipment. Thomas called upon Samuel McHose of Allen­town to perform the principal masonry work for all his furnaces. Boilers averaged $9 ,35 3 and were built by a Brooklyn manufacturer. Beam-blowing engines were pur­chased from a shop in Cold Spring, New York, at a cost of $42,000 per furnace. Details were an important part of business and Thomas frequently involved himself in estab­lishing specifications. “The engines are to have steam­-cylinders of 84 inches diameter by 9 foot stroke,” he wrote.

In tandem with furnace operations. Thomas maintained iron mines at Hellertown, Ironton, Rittenhouse Gap and in central New Jersey. Thomas soon controlled forty percent of the Catasauqua and Fogelsville Railroad (C&FRR) thus insuring the hauling of limestone and brown hemitite from the company’s mines and quarries. By the late 1860s, the company controlled the Ironton Railroad and in a few years became the principal industrial employer in Lehigh and Northampton counties. In July 1869 the second and final furnace at Lock Ridge was built. The furnaces, now designated numbers 7 and 8 in order of fire-up, completed the company’s acquisitions to that date.

Throughout its fifty-five year industrial life, the iron village of Lock Ridge was a dirt road lined with company homes for an ethnic mix of thirty-six employees. Pennsyl­vania Germans, Scotch Irishmen. Welshmen and Irishmen manned the furnaces. By 1900, the Lock Ridge ethnic “brew” included Slovaks, Hungarians and Poles newly arrived in America from their distant European homelands. Hardly any of these workers, however, ever reached management positions. Henry Knerr, the last superintendent of the Lock Ridge operation, was the only Pennsylvania “Dutchman” to rise from the labor ranks. Many of Thomas’s relatives were given key positions at various plants and quarries owned by the Thomas Iron Co. One rather bitter Thomas employee recalled in the I 930s, “there was alot of inbreeding there.”

In the Lock Ridge furnaces, and elsewhere throughout the Lehigh Valley, the magic mixture of limestone flux, iron ore and coal was dumped into the furnace and melted to settle at the base of the 3,000 degree Fahrenheit caul­dron. Slag then floated to the top of the furnace while the molten pig iron (called “pig” because it was later cast into bars called pigs) flowed out of the furnace maw and was directed downhill into the cast house via sand troughs where it settled in to specially constructed packed-sand floor beds. The liquid iron occasionally splashed up on the legs of workers. though oddly enough no major industrial accident was ever reported at Lock Ridge. To avoid these incidents workers donned heavy leather aprons and wool leggings for protection. In addition, nineteenth century ironworkers stood on platform shoes with thick wooden soles. The shoes, strapped to workboots, enabled a man to walk across the searing floor of the cast house.

The twelve-hour day ended with cooling pigs of iron. Each man then received a financial reward for his efforts that was considered quite substantial for the day. It has been recorded that farmers. idle during the winter months, often sought the demanding. spirit-lifting labor of the furnace. The furnace blacksmith, for example, was con­sidered a well paid specialist. Records kept by the Thomas Company showed a “Smithy” could earn at least $2.50 a day at the Lock Ridge operation.

A pioneer in public relations, Thomas was sensitive to the religious beliefs of the Christian workers and their wives at Lock Ridge. As a result, he donated property to the community for the construction of Memorial Presby­terian Church and cemetery in the summer of 1870. Addi­tional property and financial contributions to the workers went to the building of a schoolhouse in 1874. The company’s generous financial aid supported the village school for many years.

Life in the iron village was regimented. A boarding house was built for “bachelor” workers and stood in harsh contrast to the ornate Superintendent’s House that still stands today, a short distance from the furnace site. From the Superintendent’s House, the ironmaster, as he was called, watched workers trudge off to the furnaces each morning to fuel the foes of the industrial Age.

At Lock Ridge, tunnels were burrowed under the foun­dation of the furnaces. Though dry today, these subterran­ean tubes carried the waters of the nearby Swabia Creek into the plant to run the steam engines and cool the fur­naces. Later, a unique hydraulic system was employed to lift various elevators inside the plant.

A narrow-gauge railroad was even built within the con­fines of the plant to haul ore and supplies from the C&F cars which pulled up outside the furnace. A narrow-gauge locomotive is believed to rest at the bottom of a water­-filled minehole near what is now the Alburtis Rod and Gun Club. In the summer of 1979, several Allentown scuba divers attempted to locate the locomotive but failed to bring any substantial evidence to light. It is hoped that the artifact will be recovered at a future time to further illuminate the history of the Alburtis furnace.

It wasn’t until the Depression of 1873 that the Thomas Iron Co. lost its competitive edge in iron production. With larger furnaces using purer grade iron ores from the Great Lakes region, Pittsburgh soon grew to become the nation’s iron and steel leader. In Bethlehem, John Fritz of the Bethlehem Iron Co. convinced the company’s board of directors that the new bessemer convertor process for making steel was the wave of the future. By 1900, Bethle­hem Iron had become Bethlehem Steel, the second largest steel producer in the nation today. Fritz, a contemporary of Thomas, proved to be more of a visionary, anticipating new technology and customer demands. Despite Fritz and the movement of iron and steel to the west, the Thomas Iron Co., undiversified and showing age, managed to keep afloat beyond the founder’s passing and on into the twentieth century. Death came quietly to the company, though the funeral was not unexpected.

Steel jackets, ironically manufactured by Bethlehem Steel, were installed in both furnaces at Lock Ridge during World War I. Anticipating a post-war boom, Thomas Iron attempted to update its ailing furnaces in Alburtis. The in­vestment was too little, too late. The fires of Lock Ridge furnace were extinguished forever in December 1921. The great stacks of 7 and 8 were eventually dismantled and the new Bethlehem steel jackets were sold for scrap. An Albur­tis family purchased the site and profited briefly by ped­dling the remains of the furnace; slag was sold by the truck­load for road fill. By 1927, the last of the Thomas furnaces was closed at Hokendauqua and Lock Ridge had already fallen into ruin.

Today, Lock Ridge Furnace stands as a silent reminder of immigrant determination to build a Pennsylvania indus­try and leave a legacy.


Lehigh County has partially restored Lock Ridge Fur­nace. Prepared for the United States Bicentennial celebra­tion, Lock Ridge Furnace Park hosts the remains of the twin furnaces, the C&F Railroad grade, the blacksmith’s house, oil house and weighstation, where incoming sup­plies were weighed and distributed and where workmen received their wages. The park is open through the winter months with week-end tours of the furnace interior con­ducted from April to November. Each year tourists visit Alburtis to enjoy craft shows, square dancing and histori­cally related lectures which recall past glories.


The author wishes to thank the Lehigh County Historical Society for their assistance in the preparation of this piece, as well as Dr. Mahlon H. Hellerich and the Office of Archives and Mu­seums of Lehigh County.


Louis J. Varricchio, a native of Allentown who recently served as editor of the Weekly Free Press in Emmaus, is a freelance writer now residing in Tempe, Arizona.