By Kevin K. Olsen, Montclair State University,


For most readers of The Indicator, the New Jersey shore is a place for vacations, and unless they are oceanographic chemists, “working” at the shore probably means having sold tee-shirts or pizza on the boardwalk during school vacations. However the shore region and the Pinelands beyond the beach were home to a number of chemical industries throughout the states history.


Many of the industries were located in the New Jersey Pinelands. This is a region of low, undulating hills and sandy soils on the Outer Coastal Plain. Holding over 17 trillion gallons, the Cohansey Aquifer underlines much of the region. The aquifer is very shallow and where it lies at or near the surface feeds the many streams of the region and produces its characteristic bogs, marshes, and swamps. The streams of the Pinelands are nutrient-poor. The early settlers of the region noted the nutrient-poor soils and named it the Pine Barrens.  The forest resources of the region were anything but poor. There are low, dense forests of pine and oak with stands of cedar and mixed hardwoods bordering the wetlands. These forests provided the raw materials for the production of charcoal, pitch, tar, and turpentine.  Approximately 1.1 million acres of the Pinelands were set aside in 1979 as the Pinelands National Reserve. Occupying 22% of New Jerseys land area, it is the largest area of openspace between Boston and Richmond. In 1983 the area was designated a U.S. Biosphere Reserve by UNESCO, and in 1988 it was designated as an International Biosphere Reserve.


The best known industries in the Pinelands were the ironworks. At the height of the industry about thirty ironworks were active. Two of these works are preserved as museums, Allaire Village ( in Farmingdale, and Batsto, in the village of Hammonton, and inside the Wharton State Forest ( Unlike the ironworks of northern New Jersey that exploited the ores mined from the regions mountains, the ironworks in the Pinelands smelted bog iron. Bog iron is formed by the precipitation of dissolved iron in groundwater. In a process mediated by the presence of bacteria, limonite and related iron hydroxides precipitate to form an iron-rich dark-orange to yellowish-brown sandstone. In the New Jersey Pinelands, bog iron is often found at the edges of cedar swamps and bogs. The water in the Pinelands has a high iron content and as it seeps through the sandy soils it can form a rusty encrustation. The encrustations can build up to sizeable chunks that are large enough to process on a commercial scale. The bog iron industry was active from the early 1700s to about 1850. Bog ore is not particularly rich in iron and is difficult to process in large quantities. Competition from the iron industry of southeastern Pennsylvania caused the demise of the bog-iron industry.  The skills required to build and operate high-temperature iron furnaces could also be used in the production of glass. Most southern New Jersey ironworks eventually became the sites of glass manufacturing operations. The abundant sand provided the raw material, and new railroads brought coal from Pennsylvania. It is not the purpose of this essay to describe these well-documented industries and the reader should consult Iron in the Pines: The Story of New Jerseys Ghost Towns and Bog Iron by Arthur D. Pierce, Rutgers University Press or the classic Early Forges & Furnaces in New Jersey, by Charles S. Boyer, University of Pennsylvania Press.


Intimately linked to the iron industry in both northern and southern New Jersey was the production of charcoal. Charcoal was critical to the iron-smelting process because it burns at very high temperatures and has an high energy density. Even the driest cordwood does not burn hot enough to smelt iron. In the years before the Civil War, charcoal was the major source of fuel for the south Jersey ironworks. Once the ironworks began to close and new railroad connections made fueling glass furnaces with coal practical, charcoal making declined in importance but continued sporadically. The last commercial charcoal burn in the Pinelands took place in 1974. Charcoal was also used by blacksmiths, can serve as a filter medium, and as a source of carbon in many industrial processes.  Charcoal is produced in the fractional distillation of wood under conditions of controlled combustion.  Wood must be heated to 482°F at which temperature it decomposes into solids, gasses, and water vapor. If too much air is introduced during the heating process, the wood burns and turns to ash. But if the amount of oxygen remains low, the volatile gasses and water escape from the wood and the remaining solids turn to carbon. Properly made charcoal is between 75 and 90% carbon with only a small amount of ash. One metric ton of charcoal contains 30 GJ or 12,800 BTU/lb. of energy according to figures published by Washington University.


The traditional method of making charcoal is to use a circular clearing in the forest that has been raked clean and leveled. This area was referred to as the “pit” even though in many instances the floor level was raised anywhere from a few inches to as high as 18 inches above the level of the forest floor. Sometimes the edge of the pit was delineated by a ditch and in other places by an earthern berm. Archaeologists have measured pits in the New Jersey Pinelands ranging from 20 to 40 feet in diameter.  The typical charcoal pit in the New Jersey Pinelands used thirty cords of wood (a cord of wood measures 4X4X8 feet or 128 cubic feet) although the largest documented pits could hold up to 100 cords of wood. The wood was cut into 3 or 4 foot lengths and stacked on end. The resulting charcoal kiln was a beehive-shaped pile of neatly stacked wood about six to ten feet high. If there was a central chimney open to the atmosphere, the pit was the chimney type and if the top layer of wood was shaped into an arch, the pit was of the arch type. In either case the wood was covered with a layer of dirt or turf which would exclude oxygen. Burning kindling was dropped down the chimney, or placed in the arch, to start the wood burning. By opening or closing holes in the layer of dirt, the charcoal burner carefully regulated the amount of air allowed into the mound. The charcoal burn required about 1 to1.25 days for every cord of wood and the typical burn lasted two weeks.


The burn required constant attention so the charcoal burner, or collier, lived in a small hut or turf-covered cabin near the pit for the duration. When the burn was over, the pit was raked open. The typical yield was between 540 and 600 pounds of charcoal per cord of wood.  Permanent charcoal kilns were shaped like squat bee hives and constructed of brick but this type of kiln was not used in New Jersey. Descriptions of charcoal kilns can be found in the Encyclopedia of New Jersey and an article about them, appeared in the 1997 Bulletin of the Archaeological Society of New Jersey.


Another important industry in the Pinelands was the production of naval stores. This is the collective name for the tar, resin, pitch, and turpentine which were vital for the construction and maintenance of wooden ships. Mariners used tar to preserve standing rigging from decay and to waterproof timbers. A sailing ships rigging is divided into the running rigging and the standing rigging. The running rigging are the ropes that are in constant motion because they are used to control the sails. The standing rigging are those ropes permanently fixed in place that help support the masts. Standing rigging took a beating from the elements and had to be coated with pine tar for protection. Even when tar produced from coal became widely available in the early 1800s, pine tar was regarded as being better suited for coating ropes. The organic chemists at Montclair State suspect that coal tar has a much higher proportion of benzenes and other light hydrocarbons. These would tend to dissolve the naturally occurring oils in hemp rope and cause it to become brittle. It was the seamans practice in the era of the sailing navies was to use tar as a sort of hair gel to keep hair out of their faces. This gave seaman the nickname tar or Jack Tar.


Shipwrights used pitch to caulk the seams between the planks of wooden hulls. It was mixed with oakum (fibers created by picking apart old ropes) and hammered into the seams between hull planks. It was also used to seal the seams between deck planks. These seams were called “devils” and pitch was “paid” into them. A practice that gave rise to the expression “having the devil to pay.”


Turpentine was used to manufacture paint. (Salt water is a very harsh environment and readers who have served in the Navy will remember these three rules; “If it wears brass, salute it. If it is brass, polish it. If it does not move, paint it!”) At the time New Jersey became a colony, England was importing naval stores from Sweden. In 1703, the Swedes cut off the supply and the British government responded by offering a bounty of 4 Pounds per ton of pitch and tar and a bounty of 3 Pounds per ton for rosin and turpentine. This encouraged colonial production all along the eastern seaboard. Among other effects, it gave rise to the nickname “tar heels” for the people of North Carolina. After the American Revolution and throughout the 1800s production of naval stores continued but the industry declined in importance after the widespread introduction of iron-and steel-hulled ships. Turpentine is made from the oily resins (oleoresins) found in pine trees. An early method to harvest crude turpentine was to make a series cuts in the trunk of a pine tree. These incisions were called a “box.” A typical box started as a deep rectangular box cut into the tree trunk about one foot off the ground. This was about 4 inches deep and 8 inches long. In the trunk above this box, slanting scarifications were cut into the tree so that they formed a V with its point directed at the base of the box where a collection vessel was placed. The boxes were cut beginning in March and continued into the summer. Not surprisingly cutting boxes damaged the tree and turpentine could only be harvested for three or four years.  Towards the end of the 1800s the boxes were replaced with a system of gutters.  The distillation of the crude turpentine began with applying gentle heat until all of the resins were melted. Small fragments of bark and wood chips were skimmed off the top. Since the water had evaporated by this point a small stream of distilled water was directed into the still to keep the temperature below 316°F, the boiling point of liquid turpentine. The turpentine distilled over and was collected in wooden barrels. The distillation was halted when the percentage of water in the distillate reached 90%. At that time, heating stopped and the top of the still was removed. Rosins were then drained out of the tank and remaining residues were collected as pitch.


Rosin was used in the manufacture of paints, varnishes, adhesives, and when mixed with tallow was used to make shoemakers wax. Rosins is used on bows for violins and other string instruments. Powdered rosins are used by both dancers and athletes to prevent shoes from slipping. Stickier than rosin, the pitch was used for caulking the seams of wooden ships and for general waterproofing. In 1847, 2200 barrels of tar, pitch, turpentine and rosin were produced in New Jersey.


As the forests in the northern states became depleted, the industry gradually migrated southwards until turpentine production became concentrated in the southeastern states and Florida.


While the production of rosins, turpentine, and pitch all used the resins of the pine trees, tar was made from pine logs. Sometimes the waste wood and pine stumps left over from the production of turpentine were used as the raw material for tar production. In the Pinelands, tar was produced in temporary kilns similar to charcoal kilns. Only one tar kiln in the Pinelands has been investigated by archaeologists. A polygonal kiln 35 feet in diameter was discovered in Galloway Township, Atlantic County. As it was located at the site of the Gloucester Furnace, archaeologists first thought that it was a charcoal kiln. Both types of kilns are temporary structures but there are significant differences.


Unlike like charcoal kilns, tar kilns were polygonal and, if the example found in Galloway is typical, were larger in diameter. Tar kilns were usually constructed on a slope or along the bank of a swamp. This was to allow the molten tar to collect at the bottom of the kiln and drain through a wooden trough, hollow log, or other channel. The tar was collected in a barrel placed downslope. Construction of the kiln began with creating a shallow, concave pit lined with clay. The clay lining was only two to four inches thick. The opening of the collection trough sat at the lowest point of the pit. The walls of the kiln were made from notched, freshly cut green logs laid horizontally. Inside this enclosure “dead wood” was laid with the long axis of the logs pointing outwards from the center and the narrow ends of the logs nearest the center. The dead wood was covered with a layer of stumps and other waste woods.  The whole structure was covered with earth or turf so that the admission of air could be controlled.


It is thought that a kiln this size would have required about ten days to burn completely.  It was crucial during tar distillation that the burning start in the topmost layer of wood and work downwards. This allowed the tar to melt and drip downwards toward the collection trough. Depending on the production process and the source woods, pitch could also be obtained from tar kilns. Tar kilns of this type were last used in New Jersey about 1865. A complete description of this kiln can be found in the Bulletin of the Archaeological Society of New Jersey, number 59, 2004.


Readers who are concerned about chemical safety (and we all are) will no doubt wonder if it was safe to harvest a combustible substance from a burning pile of pine logs. Careful management of the kiln was critical, and there are accounts of kilns exploding in dry weather or after becoming too hot.


We usually do not think about papermaking in New Jersey, but the industry did flourish here.  The village of Harrisonville on the East Branch of the Wading River began as a mill site with a combination grist and saw mill in the 1750s. An iron forge and slitting mill were established in 1795. The property changed hands in 1832 and the new owners, seeing that the bog iron industry was declining, decided to manufacture paper. The water power that had run the earlier mills was used to power the papermaking machinery. The raw materials were the soft hay and rushes that grew in the nearby salt marshes. The mill produced heavy-butcher style paper. By 1834 the mill had a 240 foot-long paper-making machine and could produce one ton of paper per day. The mill was rebuilt after a fire in 1846 and was closed in the 1890s.  No buildings survive from the era of papermaking; they were destroyed in a 1914 forest fire.


Recovering metals from seawater has long been a dream of chemists and chemical engineers.


Of the many elements in seawater, only magnesium, the third most abundant element in the ocean, has been extracted on a commercial scale.  Prompted by the war-time demand for magnesium, in 1941 Dresser Industries opened the Harbison Walker - Cape May Works (also known as the Northwest Magnesite Plant) nearSunset Beach on the Cape May peninsula. The plant was on the west side of the peninsula only a few yards from Delaware Bay. The plant clarified sea water from Delaware Bay and mixed it with limestone to precipitate magnesium hydroxide. This solution was filtered and the filtrate was fired in rotary kilns to produce magnesite refractory brick. While much of the magnesium produced during World War Two was used for aircraft manufacturing, the magnesium bricks produced in Cape May were used instead to line steel furnaces. The plant continued in operation until 1983 when it was demolished. Today world magnesium production is 429,000 metric tons per year. Extraction of magnesium from seawater is mostly confined to the United States and Israel. The Israeli magnesium industry is centered on the Dead Sea.


The site of the plant in NJ consists of 125 acres of undeveloped beach front that is being transformed into a bird sanctuary. Although the site was cleaned up under the Environmental Cleanup Responsibility Act (ECRA), a landfill containing magnesium carbonate and limestone remains. The pH of the soils on the site is high and this has prevent native vegetation from reestablishing itself; the one exception being a native alkali saltgrass (Puccinellia sp.).To reduce the pH of the soils, dredge spoils from the Cape May Canal have been mixed into the ground. The organic material contained in the dredge spoils will support beneficial microbes that will eventually lower the pH through oxidation. Unfortunately the dredge spoils are themselves alkaline pH (8.1) and have high levels of soluble salts. For the immediate future, only alkali and salt-resistant plants will be growing on the site.


Some years ago, the author was giving a second-last-before-lunch presentation at a chemistry symposium. Nervous about the presentation, I skipped breakfast. As it happened everything went fine and I took my seat to hear the last presentation before lunch. A food science laboratory had been commissioned to study why pizzas with lots of cheese taste better those without and why French fries on the New Jersey boardwalks taste so good. Itwas agony to watch the slides on an empty stomach. But I can say, that extra cheese traps volatile flavor molecules and thus enhances the pizzaʼs taste. French fries on the boardwalk taste so good because airborne salts blow in from the ocean and settle on the fries. That is the kind of chemistry I think we can all appreciate.


Beyond the Beach, some suggestions for scientific summer travel:


Allaire State Park


4265 Atlantic Avenue


Farmingdale, NJ 07727


The museum village at Allaire interprets life at the ironworks in the 1800s. Restored buildings open to the public include the workers row homes, the foremans cottage, the Allaire Mansion, the bakery, the blacksmith shop, carpenter shop, and the blast furnace. During the summer months the village is open from Wednesday thru Sunday, 12:00 PM – 4:00 PM.  This is an excellent day trip for families with young children since Allaire State Park is also home to New Jerseys official railroad museum, the Pine Creek Railroad. The railroad operates summer weekends with trains departing every half hour between noon and 4:30 PM.  Fares are $4.00 per person and credit cards are not accepted.


Batsto Village & Wharton State Forest31 Batsto Road Hammonton, NJ 08037In addition to the museum village that interprets the sites iron and glass making history, Batsto also features a nature center where visitors can learn about the ecology of the New Jersey pine lands and take guided canoe tours of Batsto Lake.


Edwin B. Forsythe National Wildlife Refuge


800 Great Creek Road


Oceanville, NJ 08231


Just over 20,000 acres of tidal wetlands, forested wetlands, upland forests and shrub-scrub habitat. The Wildlife Drive and trails are open seven days a week from sunrise to sunset.  The refuge is home to American Black Ducks, Mallards, Buffleheads, Brant, Greater Scaup, Northern Pintails, Terns, Scarlet Tanagers, Yellow Warblers, Kentucky Warblers, Prairie Warblers, Blue-winged Warblers, Black-and-white Warblers, and Pine Warblers.


Wheaton Arts Center


1501 Glasstown Road


Millville, NJ 08332


800 998 4552,


The Wheaton Arts Center is home to the Museum of American Glass, working glass studios(open to the public for demonstrations), and the Down Jersey Folklife Center. Between April and December, the center is open Tuesday through Sunday, 10:00 AM to 5:00 PM.  Admission: $10.00 Adults, $9.00 Senior Adults (62+), $7.00 Students, Children 5 and under are free.