In the early nineteenth century, Philadelphia was already home to the American Philosophical Society, the Philadelphia Museum established by Charles Willson Peale (1741–1827), and a thriving medical community. But the academy founders, members of the city’s growing professional class, felt excluded and poorly represented by the city’s established elite institutions. For its first home, the young academy rented rooms above a milliner at 94 N. Second Street that included meeting space, a reading room, and a room to keep their growing specimen collection. The first major collection acquired by the academy, a large collection of minerals purchased from prominent local geologist and congressman Adam Seybert (1773–1825) in the summer of 1812, provided the basis for the first series of lectures for the members.

While the academy’s founders considered the creation and diffusion of knowledge about the natural world important for its own sake, they also enthusiastically embraced the idea that the study of natural science built character in urban young men and was a patriotic duty that would place the sciences in the young United States on an equal level with those in the Old World. Even though membership was restricted to only those people nominated by two current members, the academy continued to grow. By 1817 it became clear that if it were to take part in the international exchange of scientific theories and discoveries as well as specimens, the academy would need to publish a journal. Scottish-born geologist and academy member William Maclure (1763–1840), a generous donor of money as well as specimens and a large number of volumes for the library, championed the idea most strongly. He was so dedicated to public science education and cooperation that he bought the academy a printing press and housed it in his own home where the Journal of the Academy of Natural Sciences was published for the first few years. The Journal, and later the Proceedings, became important natural science journals.

A History of Expeditions

In 1812, a mere month after its founding, the academy sponsored its first “expedition” to visit the zinc mines in nearby Perkiomen, Pennsylvania. As it grew in size and prestige it organized, sponsored, and staffed more expeditions, often in collaboration with the federal government and other institutions. Army topographer Major Stephen Harriman Long (1784–1864) led one such expedition in 1819 to the Upper Mississippi Valley, which included academy members Thomas Say and Titian Peale (1799–1885), to study and collect the area’s flora and fauna.

By the mid-nineteenth century, the academy’s amateur naturalists gave way to a more professional membership, reflecting a larger trend in American science. The academy continued to collect specimens from around the world through trade, purchase, donation, and sponsorship of expeditions of exploration. In 1834, it cosponsored an expedition to the mouth of the Columbia River with the American Philosophical Society. In 1838 academy members Charles Pickering (1805–78) and Titian Peale, along with several corresponding members, joined the four-year Wilkes Expedition, which explored and surveyed the Pacific Ocean and adjacent land.

The academy’s collection grew quickly throughout the nineteenth century, forcing it to move five times to progressively larger buildings. In 1840 the institution moved to a new, fireproof building at Broad and Sansom Streets where it became one of the most modern, best-equipped natural history museums in the United States. It boasted, among other holdings, the world’s largest ornithological collection. The academy made its final move in 1876, constructing a new building at the corner of Race and Nineteenth Streets, a remote location that later became the heart of Philadelphia’s cultural district. The academy’s location was further enhanced by the creation of the Benjamin Franklin Parkway as the showpiece of the City Beautiful movement in 1917.

A Bent Toward Paleontology

Paleontological work preoccupied the academy during the late nineteenth century, thanks to men such as Joseph Leidy (1823–91) and Edward Drinker Cope (1840–97).  Leidy trained as a medical doctor, taught anatomy at the University of Pennsylvania and later Swarthmore College, and was a curator at the Academy of Natural Sciences from 1846 until his death. He described some of the first dinosaur fossils in America and led the field of vertebrate paleontology for most of the nineteenth century. Leidy did some collecting locally, but relied largely on field naturalists such as Cope and Ferdinand Hayden (1829–87) to send fossils from the American West.

Following early successes by men such as Leidy and Hayden, the field of paleontology exploded, and the academy was at its center, not always for the better. The most brilliant and controversial of these later scientists was Edward Drinker Cope. A student of Leidy’s, Cope was talented and ambitious, and after the Civil War he embarked on a number of expeditions of the American West that sent huge numbers of paleontological specimens back to the academy. Unfortunately, Cope maneuvered himself into a petty, and sometimes violent, feud over access to fossil excavation sites, interpretations of specimens, and prestige with fellow paleontologist O.C. Marsh (1831–99) of Yale University, a feud dubbed by many historians as the “Bone Wars.” This feud had important consequences for the academy and Joseph Leidy. Outlandish stories of the feud published in the popular press sullied the academy’s reputation, and Leidy, disgusted by Cope’s behavior and tired of being caught in the middle of the feud, eventually abandoned paleontology in the West and turned his attention to other projects and helping local organizations, including serving as the president of the faculty and head of the museum at the Wagner Free Institute of Science of Philadelphia.

Twentieth Century and Beyond

By the turn of the century, study of natural science began to shift away from museums to university biology labs. However, the academy continued to sponsor expeditions to the Arctic, Asia, Africa, and Central America and conduct original research in several fields. Years before ecology, pollution, and conservation became topics of public debate, in 1947 the academy embarked on a research agenda to study aquatic ecosystems through its Department of Limnology, and in 1948 it established an Environmental Research Division. Throughout the twentieth century, the academy conducted important research in ecology and biodiversity on its own and in partnership with other area institutions.

In 2011 the academy became the Academy of Natural Sciences of Drexel University when it formed an official affiliation with Drexel University. This partnership created a bridge between university-based biological research and museum-based natural history collecting. The relationship combined the institutions’ educational missions and resources and enhanced their ability to collaborate on natural and environmental science research. The affiliation facilitated, among other projects, creation of a joint Department of Biodiversity, Earth, and Environmental Science (BEES) dedicated to research and education in the fields of environmental science, ecology and conservation, biodiversity and evolution, geoscience, and paleontology.

The mission and motto of this new department, “Field Experience, Early and Often,” echoed the interests and ambitions of the founders of the Academy of Natural Sciences. By remaining true to the vision of its founders, America’s oldest institution of natural history remained relevant into the twenty-first century.

Matthew A. White is a Ph.D. candidate in the History Department at the University of Florida. His dissertation, “Patronage, Public Science, and Free Education: William Wagner and The Wagner Free Institute of Science 1855–1929,” was supported by grants from the Consortium for the History of Science, Technology, and Medicine (Philadelphia). He is also a museum professional with over twenty-five years of experience in museums of science, technology, and history, and is the Director of Education at the Smithsonian Institution’s National Postal Museum. (Author information current at time of publication.)

Beginning in the eighteenth century, early explorations in flight primarily followed two distinct avenues: hot-air balloons developed by brothers Joseph-Michel (1740-1810) and Jacques-Étienne (1745-99) Montgolfier in Paris and hydrogen-inflated balloons tested by the Montgolfiers’ contemporary and fellow Frenchman Jacques Alexander Caesar Charles (1746-1823). Serving as ambassador to France from 1778 to 1785, Benjamin Franklin (1706-90) witnessed and reported on such experiments to associates and friends in Philadelphia, stoking American interest in aeronautical flight.

As Philadelphia, then serving as the national capital, emerged as a focal point for ballooning in the new republic, early aeronautical endeavors in the city had mixed success. On May 10, 1784, Dr. John Foulke (1757-96) successfully recorded the first balloon flight in America, a small, unmanned paper test balloon released from the courtyard of the Dutch minister’s residence. Following Foulke’s demonstration, Maryland innkeeper and lawyer Peter Carnes’ (1749-94) ascension in a tethered hot-air balloon at the city prison yard on July 17, 1784, failed spectacularly when a gust of wind knocked Carnes from the balloon before it caught fire and fell to earth. A decade later, the exploits of European balloonist Jean-Pierre Blanchard (1753-1809) renewed Philadelphians’ interest in aeronautics; on January 9, 1793, citizens paid $2 to $5 per ticket to witness Blanchard’s ascent from the Walnut Street Prison yard at Sixth and Walnut Streets, a spectacle sponsored and attended by President George Washington (1732-99).

Ballooning Set the Stage

While public enthusiasm for ballooning waxed and waned throughout the nineteenth century, early aeronautics nonetheless fostered a public receptiveness to flying that increased as inventors turned their attentions to the problem of heavier-than-air flight. At the dawn of the twentieth century, interest in fixed-wing aircraft and other flying machines drew together a mix of scientists, engineers, part-time researchers, and enthusiasts to form a growing aeronautical community in the Philadelphia region. Notable among these individuals was George A. Spratt (1870-1934), a medical student from Coatesville, Chester County, Pennsylvania, who channeled his scientific training into the study of aerodynamics and participated in the Wright brothers’ gliding experiments at Kitty Hawk, North Carolina, in the summer of 1901. Following the Wright brothers’ success in 1903, airplanes, like balloons a century earlier, gripped the public imagination and developed initially as a form of entertainment. Between 1908 and 1915, the Point Breeze racetrack and the Philadelphia Naval Yard at League Island became popular destinations for exhibition flights and air meets sponsored by the Aero Club of Pennsylvania, which formed in December 1909 from the merger of the Aero Club of Philadelphia and the Philadelphia Aviation Society. In addition to exhibition flights, races between airplanes were also a popular attraction; locally, department store chain Gimbel Bros. (Gimbels) sponsored a 1911 contest from New York to Philadelphia that concluded at Belmont Plateau in Fairmount Park.

While the Aero Club of Pennsylvania, as well as aero clubs at local colleges and universities including the University of Pennsylvania, Haverford, and Swarthmore, brought a degree of organization to amateur aviation, American involvement in World War I served as a catalyst for the emergence of a true aeronautical industry in Philadelphia and the nation. As the War Department increasingly recognized the airplane’s potential for scouting, observation, and tactical support of ground troops, ambitious goals of producing 22,625 airplanes and 4,500 aircraft engines led to the construction of government-owned and operated facilities like the Naval Air Station Lakehurst (New Jersey) and the Naval Aircraft Factory at the Philadelphia Navy Yard. Established in 1917, the Naval Aircraft Factory quickly became a critical hub for the manufacture of flying boats, seaplanes, motors, and other accessories; by war’s end, the facility boasted over one million square feet of floor space and employed more than 3,600 workers. The region’s contributions to the war effort also included the manufacture of component parts by Philadelphia-based firms like G.E.M. Manufacturing, which specialized in aerial cameras, and the J.G. Brill Company, which produced rough cylinder motor liners at its trolley and rail car plant at Sixty-Second Street and Woodland Avenue, as well as the training of aviators and support personnel at the Essington Aviation Station located on the former site of the Lazaretto quarantine station.

Military Influence Persists

Following the war, the symbiotic relationship between government and the nascent aviation industry remained critical, as military needs continued to influence industrial production and priorities, particularly in Philadelphia. Most significantly, the Naval Aircraft Factory scaled back its workforce to approximately twelve hundred workers and, throughout the 1920s, shifted focus from the production of aircraft to research and development of experimental designs. Initially, private industry followed suit and increasingly focused on the engineering and testing of materials and component parts until federal legislation expanding airmail service contracts for private carriers spurred demand for new and more efficient aircraft. Among others, aviation enthusiast Harold F. Pitcairn (1897-1960) capitalized on the 1925 Kelly Air Mail Act to establish a manufacturing facility for light utility aircraft at his Bryn Athyn airfield under the auspices of Pitcairn Aviation, the passenger service and flying school based in Willow Grove. Renewed demand for military and civil aircraft similarly spurred companies like the Huff-Daland Aero Corporation of Ogdensburg, New York, to establish a new headquarters and production plant along the Delaware River in Bristol, Bucks County, Pennsylvania. Notably, the arrival of Huff-Daland in 1926 coincided with the opening of Philadelphia’s first municipal airport, a 111-acre facility located in the Eastwick section of the city, while public interest in the 1927 transatlantic flight by Charles Lindbergh (1902-74) and his subsequent tour, which included stops in Philadelphia and Wilmington, Delaware, likewise spurred a boom in commercial airport construction, including the William Penn Airport on Roosevelt Boulevard and the Philadelphia Aircraft Company’s airfield on Easton Pike near Doylestown.

Throughout the early decades of the twentieth century, Philadelphia’s strategic location along primary east-west and north-south arteries significantly spurred the development and growth of aeronautical infrastructure and industry in the city and surrounding region. Nonetheless, aircraft manufacturing and airfield construction contracted sharply during the Great Depression, as companies once again redirected their focus from aircraft manufacturing to component parts. Amidst this shift, the Edward G. Budd Manufacturing Company of Philadelphia distinguished itself for its innovative use of stainless-steel and a pioneering shot-welding fabrication process used to produce aircraft materials that were stronger and more resistant to corrosion. Similarly, the production of engines, rotary wings, and propellers by companies like Fleetwings Inc. of Bristol and Jacobs Aircraft Engine Company of Pottstown helped to sustain the local aviation industry until demand for new aircraft rebounded in the lead-up to World War II. As the nation mobilized for war, the Naval Aircraft Factory once again stepped up production to meet rising demand and expanded into a wealth of experimental, highly classified projects on pilotless aircraft and guided weapons systems that underscored an ever-growing emphasis on research and development. This shift solidified further in 1943, when the Naval Aircraft Factory was renamed the Naval Air Material Center and the facility’s primary duties divided into two units: the Naval Aircraft Modification Unit, which focused on the conversion of service aircraft and special weapons work, and the Naval Air Experimental Station, which conducted laboratory and materials testing. Technological research and innovation similarly dominated wartime work at the Philadelphia-based Steam Division of the Westinghouse Electric Corporation, which engineered and produced the first operational American turbojet for the U.S. Navy in March 1943.

Cold War and Beyond

Across the state of Pennsylvania, employment in the aircraft, engines, and parts industries peaked at approximately 45,000 workers in July 1944; from there, employment and production statistics steadily declined into the postwar period, as industries struggled with the effects of demobilization and a market over-saturated with readily available used aircraft. In response, the Naval Air Material Center doubled-down on the research and development of specialty parts and materials, including advanced catapult systems, rocket-powered ejection seats, and improved arresting gear. Similarly, in 1947, the navy’s aircraft plant in Johnsville (Warminster), Bucks County, was converted into the Naval Air Development Station and embarked upon research in aviation electronics, medicine, and unmanned aircraft. Over the next decade, the two facilities evolved further, increasingly focusing on missile and spacecraft technologies and effectively positioning themselves at the forefront of Philadelphia’s burgeoning aerospace industry.

Throughout the 1950s and 1960s, a number of private corporations across the region  joined in these endeavors, including the Boeing Vertol facility in Ridley Park, which specialized in helicopter and rotary wing aircraft; the Radio Corporation of America (RCA) facility in Camden, New Jersey, which developed guided missile and checkout equipment; and General Electric’s Missile and Space Vehicle Department based in Philadelphia, which in 1957 received the company’s first Air Force contract to develop a reentry vehicle for intermediate-range ballistic missiles. In April 1960, General Electric broke ground on a new Space Technology Center in Valley Forge, which became the hub for the company’s Space Division and its work on a range of missile and satellite projects for the remainder of the 1960s and into the 1970s. Despite the growth of private industry in the postwar period, the aerospace industry in Philadelphia arguably reached its apex in Johnsville, which in 1959 became headquarters of the Naval Air Research and Development Activities Command. In this capacity, the facility oversaw the Naval Air Engineering Center’s work on pressure suits used by Project Mercury astronauts, as well as jet and rocket engine research and centrifuge testing to measure the effects of G-force on humans. Several Gemini and Apollo program personnel and astronauts, including John Glenn (1921-2016) and Neil Armstrong (1930-2012), trained at the facility, as well as a number of X-15 space plane pilots.

True to the aerospace industry’s increasing dependence on government contracts and projects, cuts in military spending and the consolidation of facilities toward the end of the Cold War hastened the industry’s decline in the Philadelphia region in the 1980s and 1990s. In 1986, General Electric acquired the RCA Corporation and subsequently sold its entire aerospace division, including the Camden facility, to the Maryland-based Martin Marietta Corporation (later renamed Lockheed Martin) in April 1993. Similarly, the Naval Air Research and Development Activities Command in Johnsville closed in 1996 and many of its buildings were subsequently demolished in 2001, a symbolic end to the long history of the aeronautical and aerospace industry in the Philadelphia region.

Hillary S. Kativa is the Chief Curator of Audiovisual and Digital Collections at the Science History Institute in Philadelphia. In addition to an MLIS from Rutgers University, she holds an M.A. in history from Villanova University and received her B.A. in history and English from Dickinson College. Her research interests include American political history and presidential campaigns, public history, and material culture. (Author information current at time of publication.)

Founded in 1743, the APS was an extension of Franklin’s intellectual club the Junto and an answer to London’s Royal Society. Marking a departure from British science, the founding document of the APS asserted that because the American colonies had matured, intellectuals could employ insights from their North American experience to promote human knowledge. Franklin and Bartram designated Philadelphia as the most logical headquarters because of its location, its easy access by sea, and the vibrant bookish culture fostered by the Library Company of Philadelphia, the lending library Franklin founded in 1731. Philadelphia also had the benefit of Bartram’s unparalleled botanical knowledge, as he collected and identified species of plants found only in North America.

Franklin and Bartram organized the APS to promote advancement in all fields of science. They proposed that there should be no fewer than seven members: a physician, botanist, mathematician, chemist, mechanic, geographer, and natural philosopher, in addition to a president, treasurer, and secretary. Members would meet once a month to conduct experiments in brewing, navigation, and agriculture among other subjects. Yearly membership dues (a Spanish piece of eight) funded the cost of experiments and the publication of the society’s findings, both for distribution among society members and abroad.

The APS quickly became much more collaborative than independent as it became an important international link in the exchange of scientific information. Members such as Bartram maintained ties with their British counterparts and sent specimens overseas, even during the Revolutionary War. From its earliest days, the APS made scientific inquiry a matter of international diplomacy as it elected members from around the world. The first international member of the society, elected in 1768, was the French naturalist and cosmologist Georges-Louis Leclerc (1707-88), followed a year later by the Swedish botanist Carl Linnaeus (1707-78). As its first female member, inducted in 1789, the APS chose the president of the Imperial Academy of Sciences in St. Petersburg, Princess Yekaterina Dashkova (1743-1810).

Building a Reputation

In 1769, a merger with another scholarly society in Philadelphia, the American Society for Promoting Useful Knowledge, gave the APS new vigor and initiated a series of scientific activities that solidified its mission. A crucial first step in establishing the APS as a reputable scientific authority occurred in the same year when David Rittenhouse (1732-96) observed by telescope the transit of Venus. His findings, with other observations around the globe, helped to determine the distance of Earth from the sun. Rittenhouse’s results were published in the APS’s Transactions of 1771 and distributed by Franklin across Europe, putting Rittenhouse’s findings on par with those of the Royal Society in London. In 1770, gifts from Thomas Penn (1702-75), members, and from scientific societies in Dublin and London established the APS Library.

In 1783, the APS sought to further secure its future by voting to build a headquarters, a task completed in 1789. Through a combination of members’ donations and a loan from Franklin, Philosophical Hall was constructed on Fifth Street adjacent to the Pennsylvania State House (later Independence Hall) under the direction of Samuel Vaughan (1720-1802), a friend of Franklin. Vaughan’s sense of style was also responsible at the time for gardens around Philadelphia, including that of the State House, and he designed the garden of another member of the APS: George Washington (1732-99) at Mount Vernon. With its new building, the APS also became a resource for public access to the sciences. Member Charles Willson Peale (1741-1827) housed his Philadelphia Museum at the APS from 1794 to 1811, and the University of Pennsylvania also used its space for five years beginning in 1789.

During and following the 1790s, when Philadelphia served as capital of the United States, the APS played a significant role in scientific activities and innovations of the early nation. As U.S. president, APS member Thomas Jefferson (1743-1826) sent Meriwether Lewis (1774-1809) and William Clark (1770-1838) to Philadelphia to study with other APS members, including Dr. Benjamin Rush (1746-1813), to prepare for their cross-country expedition in 1804. The APS helped to sponsor the mission, and in return the explorers contributed a huge bank of new scientific knowledge on botany, zoology, geography, and ethnology from their travels. Just as their founder Franklin was a leading statesman as well as a scientist, and especially after the success of the Lewis and Clark expedition, APS members tied their research to the service of the state and the expansion of American power. For instance, Commander Matthew Fountaine Maury (1806-73), the “Pathfinder of the Seas,” played a key role in charting the geography of the sea to support an expanding American Navy. In 1862, however, Maury was expelled from the APS for joining the Confederate Navy.

The impact of the APS extended as its members of the APS consulted on the founding of other American scientific and cultural institutions, including the National Academy of Sciences, the Franklin Institute, and the Smithsonian Institution. Ophthalmologist Isaac Hays (1796-1879), a leading member of the APS who advanced a theory of natural selection before Darwin published it in The Origin of Species (1859), was among the founders of the American Medical Association in 1847. APS membership in the nineteenth century included such prominent scientists as Alexander von Humboldt (1769-1859), Charles Darwin (1809-82), the Swiss-born Louis Agassiz (1807-73) and his wife American-born Elizabeth Cabot Agassiz (1822-1907), Louis Pasteur (1822-95), and Thomas Edison (1847-1931). The scope of the APS also expanded to an additional field of scholarship in 1884 when, inspired by the creation of the American Historical Association, the society began to elect leading historians into its ranks and created a Committee on Historical Manuscripts to promote access to its own rich history.

Isaac Minis Mays, Secretary and Librarian

The work of producing manuscript catalogues and calendars of historical documents, as well as editing the Proceedings and Transactions of the APS was taken up by Hays’s son, Isaac Minis Hays (1848-1925), who served as secretary and librarian from 1897 to 1922. An energetic leader, Hays ushered the society into the twentieth century. He improved the quality of the APS library, expanded access to the library for researchers and the public, accomplished a fifteen-year project to bind and catalog the papers of Benjamin Franklin, and created the Franklin Medal to recognize excellence in both science and public service.

The APS continued its transition to a multidisciplinary scholarly organization under the leadership of biologist Edwin Grant Conklin (1863-1952), who served in a variety of APS offices leading to two terms as president in 1942-45 and 1948-52. In addition to members such as Margaret Mead (1901-78) and Albert Einstein (1879-1955), in the twentieth century the society expanded its membership from the humanities: poet Robert Frost (1874-1963), philosopher Isaiah Berlin (1909-97), poet Seamus Heaney (1939-2013), and historian Natalie Zemon Davis (b. 1928). By the early twentieth century, in a departure from the society’s early history of collaboration with the United States military and government, members included scholars whose research questioned institutional power over the individual and reflected on access to justice. They included a philosopher of ethics and human rights, Martha Nussbaum (b. 1947), queer theorists Eve Kosofsky Sedgwick (1950-2009) and Judith Butler (b. 1956), and post-colonial theorist Gayatri Chakravorty Spivak (b. 1942).

These APS members and many others extended and elevated Philadelphia’s vibrancy, which initially made the city fit to host the society, to a truly international stage. In the second half of the twentieth century, the society also increased its physical presence in its home city. In 1959, across Fifth Street from Philosophical Hall, the APS opened Library Hall, a reproduction of an eighteenth-century structure that originally housed the Library Company of Philadelphia. In 1984 and 2000, the APS campus expanded to include two adjacent former bank buildings on Chestnut Street. Through its rich library and manuscript collection, research grants, and such prestigious prizes as the Magellanic Premium in navigation and astronomy, established in 1786, and the Barzun Prize in history the American Philosophical Society continued its mission of promoting useful knowledge. As affirmed by a mission statement adopted in 2008, the society’s activities sought to “reflect the founder’s spirit of inquiry, provide a forum for the free exchange of ideas, and convey the conviction of its members that intellectual inquiry and critical thought are inherently in the public interest.”

Brooke Sylvia Palmieri is a Philadelphia native living in London, working toward a Ph.D. at the Centre for Editing Lives and Letters at University College London. Her dissertation details the reading, writing, and publication habits of Quakers at the end of the seventeenth century and how they circulated their ideas from London to the British colonies in the West Indies and North America. (Author information current at time of publication.)

Private and university-based anatomical courses in Philadelphia dated back to the 1750s. However, the scale of anatomical education took a great leap forward in 1762, when William Shippen Jr. (1736-1808), who had studied medicine in Edinburgh, began a public course of lectures on anatomy, which included human dissections. While any man could attend—women would not be allowed to study medicine until well into the nineteenth century—Shippen intended his course to serve as an introduction to a larger medical education geared toward those interested in a medical career. Within four years, Shippen joined another Philadelphia physician, John Morgan (1735-89), to found the Medical School of the College of Philadelphia (later the University of Pennsylvania).

In spite of the first medical school emerging from Shippen’s anatomical lectures, the quality of anatomical education for the rest of the eighteenth and early nineteenth century was stymied by limited access to fresh corpses, partially the result of popular opposition to dissection. Public angst about dissection reached a boiling point in 1765 when a mob of sailors interrupted Shippen’s course and marched on his home.  Philadelphians had suspected since his earliest lectures that Shippen had stolen bodies for dissection from a church graveyard, but he explained that he only dissected executed convicts and occasionally a body from the potter’s field, a public graveyard for the poor.  Resistance also came from other physicians. Prominent physician Benjamin Rush (1746-1813) had little respect for anatomy as a standalone discipline and pushed his own physiological system for understanding human health. In Rush’s system, all diseases were caused by states of imbalance in the body, or as Rush put it “a disproportion between excitement and excitability.” Weather, emotional state, or diet, among other influences, caused these imbalances. Rush, a professor of chemistry at the Medical School of the College of Philadelphia from 1769 until his death in 1813, described anatomical study as just “a mass of dead matter. It is physiology which infuses life into it.” Rush rooted his theories in eighteenth-century approaches to medicine, and he significantly influenced medical education in Philadelphia throughout his life.

Following trends in Paris that emphasized pathological anatomy through postmortem dissections to understand disease, the generation of educators after Rush made anatomy the centerpiece of their educational system, which contributed to Philadelphia’s status as the focal point of American medical and scientific thought in the nineteenth century. During this era, with the University of Pennsylvania, Jefferson Medical College, the short-lived Pennsylvania Medical College, and three private supplemental anatomy schools, Philadelphia developed the most robust culture of anatomical education in the United States. Four Philadelphia anatomy professors—Caspar Wistar (1761-1818) of the University of Pennsylvania; William Horner (1793-1853), who succeeded Wistar at the University of Pennsylvania; Horner’s successor Joseph Leidy (1823-91); and Samuel G. Morton (1799-1851) at the Pennsylvania Medical College–wrote anatomy textbooks. Leidy even had his personal copy of his textbook bound in human skin.

One of the major differences between eighteenth- and nineteenth-century anatomical education in Philadelphia and elsewhere was an increasing focus in the nineteenth century on pathological anatomy, popularized by doctors in France.  Pathological anatomists used post-mortem dissections for the purpose of discovering the cause of death and how specific diseases affected the tissues and organs of the body. While physicians had been making post-mortem dissections for centuries, practitioners in the Paris clinics dissected thousands of cadavers and argued that disease could be observed as lesions in the tissue, as opposed to previous theories that considered specific organs as the seats of disease.

During this period, medical schools began to assemble significant anatomy collections in museums featuring objects like diseased organs, human skulls, and animal skeletons. The University of Pennsylvania’s anatomical museum (first assembled by Caspar Wistar from 1808 to 1818 and later part of the Wistar Institute) and the College of Physicians and Surgeons’ Mütter Museum (founded in 1858) represented two of the largest American anatomy museums in the nineteenth century. Many professors also incorporated artifacts from these collections into their classes. Utilizing museum collections and their professors’ lectures, students in Philadelphia learned about comparative anatomy between animals and humans, along with the supposed differential anatomy of the human races. At the University of Pennsylvania, Leidy even told his students that Black and white people were different species. As a result, in addition to its value as a medical subject, the study of anatomy carried social and political implications.

Because Philadelphia housed so many venues for dissection in the nineteenth century, anatomy professors competed for fresh corpses. Anatomists fashioned a secret arrangement with the city government, which gave them open access to potter’s fields. This arrangement yielded approximately 450 corpses per year, but Philadelphia physicians sometimes still had to ship in bodies from New York City. In 1828, Philadelphia anatomists signed a contract to ensure that each professor received a fair portion of available anatomical material, which helped alleviate tension between anatomy teachers.

The city’s most public body-snatching scandal took place in 1882, after gross anatomy had lost its central position in medical pedagogy. In 1882, Jefferson University Professor of Anatomy William Smith Forbes (1831-1905) was publicly tried on charges of stealing six cadavers for his anatomy course from the historically African American Lebanon Cemetery. While Forbes was eventually acquitted, the case revealed a previously little-known Black market in corpses that went back to the beginning of the century. In spite of scandals like the Forbes case, students continued to view dissection as a right of passage. Into the twentieth century, they persisted in a ritual of posing for photographs with cadavers, a practice that underscored the continued influence of anatomy and dead bodies on medical students and their relationship to patients and death.

The study of anatomy and Philadelphia’s role in it rose to the peak of their importance within American medicine in the antebellum era. Even after the rise of German laboratory medicine and the ascendance of germ theory in the 1870s and 1880s made gross anatomy just one subject among many in the medical curriculum, Philadelphia physicians continued to make breakthroughs in histology (microscopic anatomy) and later neurosurgery. Leidy, whose tenure at the University of Pennsylvania lasted from 1853 until his death in 1891, utilized microscopic anatomy in his lectures and for his 1861 textbook. Pathological anatomy continued to be a fruitful area of medical exploration into the twentieth and twenty-first centuries. Although gross anatomy remained important for medical students to learn the structures of the human body through anatomical education, it never again occupied the central theoretical position in medicine as it had in the first half of the nineteenth century.

While gross anatomy fell into the background of American medical education, professors at Philadelphia universities continued to make names for themselves in anatomy-related branches of inquiry, including neuroanatomy and neurosurgery.  At the turn of the twentieth century, the University of Pennsylvania emerged as one of the country’s leading centers for neuroscience. Charles Harrison Frazier (1870-1936) led a cohort of neurosurgeons in Philadelphia who contributed to the creation of the Departments of Neurosurgery at the University of Pennsylvania and Temple University. Frazier and William Gibson Spiller (1863-1940) pioneered a new surgical method for treating trigeminal neuralgia and made additional breakthroughs in treating pain in the nervous system. Together these neurosurgeons shaped the future of neuroanatomy and trained the next cohort of the country’s leading neurosurgeons, including Francis Grant (1891-1967) and Robert Groff (1903-75).  Through the neurosciences, Philadelphia continued to maintain a prominent position in the American medical profession, and anatomy continued to occupy a central role in the production of medical knowledge.

Christopher Willoughby is a Ph.D. candidate in the History Department at Tulane University in New Orleans, where in 2012 he also received his master’s.  He is completing his dissertation entitled “Pedagogies of the Black Body: Race and Medical Education in the Antebellum United States,” which has been supported by grants from the National Science Foundation and the Consortium for the History of Science, Technology, and Medicine (Philadelphia).  He was the 2014 winner of the W. Curtis Worthington Jr. Prize from the Medical University of South Carolina’s Waring Historical Library, for the best graduate student essay in the history of health science. (Author information current at time of publication.)  

This material is based upon work supported by the National Science Foundation under Grant Number 1353086. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Eighteenth-century almanacs contained various kinds of astronomical data, including schedules of eclipses and sunrise/sunset tables. Some of the more popular Philadelphia imprints included Poor Richard’s Almanack, printed by Benjamin Franklin (1706–90), and Der Hoch-Deutsch Americanische Kalender, printed by Germantown’s Christopher Saur (1693–1758). Almanacs commonly included a Zodiac Man or Man of Signs, an astrological diagram that showed how planets governed specific parts of the human body. Historically, though the practice was on the decline by the eighteenth century, the image was intended to be used in conjunction with the almanac’s astronomical data to diagnose illnesses. However it was used, the relevancy of astronomical information in almanacs was contingent upon one’s geographical location, prompting local residents, notably David Rittenhouse (1732–96), to provide almanac calculations for the vicinity of Philadelphia.

David Rittenhouse was a celebrated early American astronomer whose work on the 1769 transit of Venus brought him transatlantic fame. A transit of Venus occurs when the orbit of Venus passes between the sun and the earth, a rare though predictable phenomenon that occurs twice separated by a gap of roughly eight years after a longer gap of over one hundred years. Not to miss a literal once-in-a-lifetime opportunity, the American Philosophical Society organized a committee consisting of Rittenhouse, William Smith (1727–1803), John Lukens (1720?–89), and John Sellers to take observations in Norriton, near Rittenhouse’s home. A second observatory was constructed in the State House Garden. The Royal Society of London published Rittenhouse’s delineation of the transit, and the American Philosophical Society released an account of the committee’s doings in the first issue of its Transactions, in 1773. This work was met with approval from European scientists. Rittenhouse supplied local astronomers, often using his mechanical talents to make complex and beautiful astronomical instruments. In addition to crafting some of the equipment for the observatories at Norriton and the State House, he made two orreries, mechanical devices for studying the movement of planets, for the College of New Jersey in 1770 and the University of Pennsylvania in 1771.

School Observatories

Local colleges and universities maintained a number of impressive observatories between the eighteenth and twenty-first centuries, but a Philadelphia city high school became one of the most technologically advanced institutions in the country in 1837. The city set aside $50,000 for the establishment of Central High School, which included $10,000 to build and furnish an astronomical observatory and library. Sharon Female Academy, founded by John Jackson (1809–55) in nearby Darby, seeking to emulate Central High, acquired a similar observatory and telescope.

Use of telescopes was not exclusive to observatories. Popular speakers used telescopes to teach astronomy in lyceum halls. In the 1840s, Irish lecturer Dionysius Lardner (1793–1859) offered his take on the theory of “The Plurality of Worlds,” an early argument for extraterrestrial life, while traveling through Philadelphia. The argument posited that if God had made other planets, they must be inhabited. Through Lardner’s performances telescopes became a means of visualizing intelligent design.

Popular thirst for astronomical knowledge, coupled with school curricula, encouraged local markets for textbooks and scientific instruments. Ezra Otis Kendall (1818–99), who taught at Philadelphia High School, authored Uranography and Atlas of the Heavens, which appeared in various editions in the 1840s and 1850s. The latter contained maps of stars and constellations. Kendall preferred color-printed star charts that depicted white stars on a blue field because he felt this better represented the nature of the heavens, Kendall’s charts also eschewed fanciful representations of constellations that confused his students. Fellow Philadelphian, Henry Whitall (1819–87), in Treatise on Fixed Stars (1850), followed suit. Testimonials for Whitall’s charts suggest that they were used by pupils of various ages, male and female alike. Women, too, wrote astronomy texts. Hannah M. Bouvier (1811–70), a resident of Crosswicks, New Jersey, wrote her Familiar Astronomy, a Philadelphia imprint, in 1855. The fifth part of her work dealt with practical astronomy, or the use of astronomical instruments. Philadelphians could visit local manufacturing companies, including McAllister & Brothers and James W. Queen & Co. These companies made telescopes, celestial globes, and various astronomical tools and glass lenses. In the 1870s and 1880s, James W. Queen & Co. advertised Henry Whitall’s “Moveable Planispheres,” large printed or brightly painted paper disks that could be rotated to determine visible stars for a particular time and date.

Other Astronomical Societies

Philadelphia’s culture of astronomy spawned a number of popular astronomical societies in the late nineteenth and twentieth centuries. In 1888, residents of Philadelphia and Camden met in New Jersey to found the Camden Astronomical Society, one of the oldest amateur astronomy clubs in the country. Edmund Read Jr. (1859–1923), a Camden businessman, became its first president. For the first thirty-five years, the society held its meetings at Read’s house. In 1927, it became the Rittenhouse Astronomical Society, meeting at the Sproul Observatory, built in 1906, at Swarthmore College. Newly renamed, the society, with the cooperation of the Historical Society of Pennsylvania, American Philosophical Society, and other area institutions, did much to promote the bicentennial of Rittenhouse’s birth in 1932, including establishing the Rittenhouse Medal, an award for outstanding achievement in astronomy. When the Franklin Institute opened a museum on the Benjamin Franklin Parkway, the society began to meet there, taking advantage of the new Fels Planetarium and Institute Observatory. Other local societies included the West Jersey Astronomical Society (founded 1967) and student-run societies at colleges and universities, such as the Physics and Astronomy Club at the University of Pennsylvania.

Well-established scientific institutions ushered in popular interest in astronomy, too. In the late twentieth century, Derrick Pitts (b. 1955) transformed the Franklin Institute’s astronomical programs. Pitts began working at the Franklin Institute as a college student in 1978 and became chief astronomer in 1990. Pitts was influential in creating the “Space Command” permanent exhibit, which provided children a hands-on experience with astronomical artifacts. In 2004, Science Spectrum magazine named Pitts one of the fifty most important African Americans in research science. In 2008, Pitts became the host of SkyTalk on WHYY Radio, a weekly broadcast of astronomical news made accessible for a popular audience. He became a NASA Ambassador in 2009. Pitts, the Franklin Institute, and the Rittenhouse Astronomical Society held various educational astronomy events during the Annual Philadelphia Science Festival, including a citywide telescope night.

Between the eighteenth and the twenty-first centuries, Philadelphians maintained a steady interest in astronomy. Scholars and popular practitioners looked to the sky to answer various questions—medical, religious, philosophical, and scientific—all means of finding their place in the universe.

Jessica Linker is a doctoral candidate at the University of Connecticut, Storrs, and the recipient of fellowships from a number of Philadelphia-area institutions, including the Library Company of Philadelphia, the American Philosophical Society, and the McNeil Center for Early American Studies. Her work focuses on American women and scientific practice between 1720 and 1860. (Author information current at time of publication.)

Philadelphia’s connections with the Atlantic predated William Penn’s founding of the city in 1682. Imperial rivalries among European powers in the seventeenth century made the Delaware Valley a site of colonization, conflict, and diplomatic wrangling. In 1638, the powerful Swedish monarchy established the colony of New Sweden in the area that later became portions of Delaware, Pennsylvania, and New Jersey. The colony survived until 1655, at which point the Dutch Republic conquered it and incorporated New Sweden into New Netherland. Less than ten years later, in 1664, the English took over New Netherland (renaming New Amsterdam as New York in the process), although the Dutch recaptured the colony during the Third Anglo-Dutch War (1672-74). The Treaty of Westminster (1674) relinquished New Netherland to the English. Such contests among European monarchies and republics gave the Delaware Valley a cosmopolitan hue. Before Penn arrived, Lenape people lived alongside Swedes, Dutch, Finns, and Germans; enslaved African people have been documented around the Delaware region from 1639.

Within a few decades of the city’s founding, Philadelphia had become a bustling port city and a center of transoceanic trade. Commercial networks bound Philadelphia to the Atlantic World. By the 1750s, Philadelphia had outgrown Boston to become the busiest port in British America. Its shipping carried flaxseed exports to Ireland and sugar grown by enslaved people in the Caribbean for refining along the Delaware waterfront. Philadelphia, in other words, quickly became integrated into the dense web of connections stretching across the Atlantic and beyond. From the beginning, pirates took advantage of these connections as they preyed on vessels. William Penn discovered to his dismay in a 1699 visit to his city that pirates thrived in Philadelphia, where they received significant support from some of the city’s well-to-do residents and royal officials, and from whence they ventured to target Muslim pilgrims in the Indian Ocean.

Religious Freedom, Economic Opportunity

Transatlantic migration peopled early Philadelphia and its surroundings. Irish, English, Welsh, and German Quakers accompanied Penn across the ocean, drawn—like other dissenting groups—by Penn’s promise of the religious freedom denied to them in the Old World. Other newcomers in the eighteenth century, frequently from the British Isles and Germany, flocked to the rich agricultural land to the west of the city. Their small farms offered better economic opportunities than could be found in Europe, giving the region a reputation as “the best poor man’s country.”

But that land belonged to other people and, consequently, European immigration to the Delaware Valley assumed a settler colonial character marked by diplomacy and conflict. Negotiations between Lenape people and Europeans in Greater Philadelphia became an important, if much mythologized, part of the early history of the region. Some Native Americans appear to have preferred dealing with pacific Quakers and established productive relationships with them. At least in the beginning, Penn and Quakers seemed to negotiate in good faith. However, as time passed, more and more Europeans arrived in the region, eyed Native American lands covetously, and plotted to appropriate further territory for themselves. By the mid-eighteenth century, Scots Irish settler colonials to the west of Philadelphia blamed the colony’s Quakers for checking further conquest. In 1763, a marauding band known as the Paxton Boys massacred the residents of a Susquehannock settlement in Lancaster County that had been on good terms with the colony. Such instances reveal how voluntary European migration across the Atlantic led to the violent expropriation of the region’s Native peoples.

Not all passages across the ocean, though, were voluntary. Indentured servitude and African enslavement—the first a temporary form of unfree labor, the second a permanent one—also crossed the Atlantic. Some European immigrants could pay their fare, but those who could not traded up to seven years of their future labor for passage to the Americas. Conditions indentured servants experienced varied wildly across different times and places, but most did not have easy lives. The German schoolmaster Gottlieb Mittelberger sought to discourage such emigration from his homeland. His Journey to Pennsylvania (1756), based on his voyage from Rotterdam to Philadelphia and his subsequent sojourn in Lancaster County, did not pull any punches about the misery and exploitation that indentured servants and other immigrants often faced.

Trafficked African people, assigned by their captors with the inheritable status of enslavement, also arrived in Philadelphia, sometimes on ships outfitted in the city. In the early years of the colony most came from the Caribbean. However, when that supply became more fraught, as it did during Seven Years’ War, Philadelphian traffickers turned to direct importation from Africa. At the beginning of the American Revolution, Philadelphia contained roughly seven hundred enslaved people, who brought with them elements of African and Caribbean culture like pepper pot soup. Philadelphia and its hinterland—where enslavers held over two thousand more people as property—never developed the export-oriented plantation economy that flourished in Virginia, the Carolinas, and the Caribbean. That said, enslaved people served in households, craft industries, and aboard ships. Furthermore, Philadelphians who did not enslave people themselves often purchased the products of enslaved labor, invested in slaving voyages, and facilitated the buying and selling of their fellow human beings.

Clashes Abroad Reverberate in Philadelphia

A region scarred by Black enslavement became a cradle of white liberty over the middle decades of the eighteenth century. As the foremost port in British North America, Philadelphia played a critical role during the Seven Years’ War, the Imperial Crisis, and the American Revolution. Each of these upheavals had Atlantic origins and ramifications. The struggle between Great Britain and France in Europe reverberated in the Americas. Similarly, events that occurred in the Americas, like George Washington’s military encounter with Joseph Coulon de Jumonville in Fayette County, Pennsylvania, rippled across the Atlantic as well. For Philadelphians, the backdrop of conflict among great powers intensified existing transatlantic connections and created opportunities for new ones. Benjamin Franklin spent considerable time in Great Britain in the 1760s and 1770s trying to prevent war between Great Britain and the thirteen colonies, as well as securing jobs for his friends and associates. Franklin had long been an Atlantic celebrity and his growing disillusionment with Great Britain represented the fraying political and intellectual links between Parliament and its American possessions.

Over these years Philadelphia and its surrounding region became a key battleground in the age of Atlantic Revolutions. Between 1770 and 1833, violent upheavals transformed France, Haiti, and vast colonized regions of North and South America into republics. In 1776 the Second Continental Congress, composed of delegates who were often born and educated in Europe, met in Philadelphia to sign the foundational document of the new United States. The Declaration of Independence reverberated across the ocean and reflected the influence of transatlantic thought. Its authors presented facts to the candid world and addressed a much broader audience than the residents of the thirteen colonies. The draft of Thomas Jefferson also revealed the western drift of Enlightenment ideas. He adapted, for instance, the claim of the seventeenth-century English philosopher John Locke that men had the right to “Life, Liberty, and the Pursuit of Property.” But the declaration, and the new republic it announced, were also shaped by Atlantic World slavery. As scholars have demonstrated, ideas about white freedom and liberty developed in tandem with racialized ideas about Black enslavement and submissiveness. Jefferson’s initial draft of the declaration placed the onus for slavery solely on Great Britain. From London, it prompted the lexicographer Dr. Samuel Johnson to wonder why the loudest cries for liberty emanated from the mouths of enslavers.

The Imperial Crisis and the American Revolution severed links to Britain. For some in the Delaware Valley the divorce proved hard to imagine. By no means did all residents in the region flock to the Patriot cause, and “Loyalists” who wanted to maintain relations with the mother country could be found among both the economic elite and ordinary people. The Delaware Valley’s Atlantic merchants confronted a difficult dilemma. Ties to the British Empire granted local merchants access to imperial markets, not least in the Caribbean, where food grown in Philadelphia’s fertile hinterland had been exchanged for sugar and cash crops. War cut off such long-established trading routes and led to the questioning of loyalties. Quaker merchants like Henry Drinker often had deep ties to Great Britain. Drinker and his wife Elizabeth faced the challenge of trying to thread the needle between making concessions to revolutionaries while maintaining their Atlantic connections. Revolutionaries eventually arrested him for treason, imprisoning him in Virginia, while Elizabeth navigated life in British-occupied Philadelphia during 1777-78. After regaining control of the city, Patriots held 638 “Tory” collaborators as suspected traitors. The Drinkers, embedded in Atlantic World networks, suffered as they attempted to navigate the complex politics of the Revolutionary era. Other Philadelphian merchants turned their gaze to the west, looking for new markets in China and the Pacific.

Ripples of the American Revolution

The Revolutionary War, like the Seven Years’ War before it, recalibrated Atlantic relations in other ways, too. At Valley Forge in 1777-78 the Prussian officer Baron von Steuben helped to drill George Washington’s army. The British evacuated Philadelphia in June 1778 and retreated to New York. Around three thousand Philadelphian loyalists left the city with the British military forces, joining a wider exodus of Tories and their allies (including enslaved Black Americans who had been promised freedom in exchange for military service) to Canada and Britain. Von Steuben’s work at Valley Forge helped Washington fight the British to a draw at Monmouth. A few months before Patriots retook Philadelphia, Benjamin Franklin, having been dispatched to Paris, steered the rebel colonies into a crucial alliance with France that helped to determine the outcome of the war. The decision to use Franklin as a diplomat proved a sound one. He fascinated the French, who saw him as the premier example of American genius, and he played his role with aplomb.

In the decades following the American Revolution, Philadelphia remained closely connected to the political currents of the Atlantic World. The ideas of the American Revolution were carried east and south. Revolutions erupted elsewhere—in France, in other parts of Europe, in Haiti, and in Spanish America. The career of Thomas Paine indicates their entangled paths. Paine, who was born in Norfolk, England, had been convinced by Franklin to go to the Americas. Arriving in Philadelphia in late 1774, his influential pamphlet Common Sense made the case for revolution in plain language that appealed to a wide readership. In the doldrums of 1776, Paine’s The American Crisis helped buoy Patriot morale. After the American Revolution ended, Paine traveled to France and served as a member of the National Convention, where he narrowly avoided the guillotine after falling out of favor with leading Jacobins. Paine’s career as an Atlantic revolutionary, with Philadelphia at its center, demonstrates how ideas easily crossed oceans.

As a major port city and an Atlantic World hub, Philadelphia often welcomed revolutionaries like Paine, while selectively supporting revolutions elsewhere. French Minister Edmond-Charles Genêt, also called Citizen Genêt, arrived in Philadelphia to a rapturous welcome in 1793. Genêt angered George Washington by attempting to subvert Washington’s proclamation of U.S. neutrality in the brewing conflict between Great Britain and France. Another figure to become embroiled in partisan battles of the early republic was the Polish nobleman Tadeusz Kościuszko. Having fought with the colonials during the American Revolution and then for Poland against Russia and Prussia, in 1797 he returned as a political exile to the United States, where he lived briefly in Philadelphia until leaving for Europe in 1798. Kościuszko wrote a will that named Thomas Jefferson as the executor, dedicating his estate to purchasing the freedom of enslaved people and providing them with an education.

Exiles Find a Home

Whether as a place of refuge from revolution and reaction or as a source of support for insurgents, the Delaware Valley became enmeshed with tumultuous upheavals across the Atlantic. When revolution erupted in Haiti in 1791, French masters fled the island, forcing many of the people they enslaved to join them. The exiles who arrived in Philadelphia brought firsthand accounts of the hemisphere’s first Black-led revolution, which energized both abolitionist and anti-abolitionist politics. Another Francophone uprooted by revolutionary wars was Joseph Bonaparte, who fled to the United States after his brother Napoleon’s defeat at Waterloo. Following a short sojourn in Philadelphia he moved out to an estate in nearby Bordentown, New Jersey, where he spent most of his remaining years. Supporters of the Greeks in the Greek War for Independence from the Ottoman Empire raised money for the cause and even tried to persuade the United States to intervene. And in 1848, citizens gathered on Independence Square to welcome the proclamation of a new French Republic. People did not always like the direction foreign revolutions took, but Philadelphians, both Black and white, recognized their city’s place in a revolutionary Atlantic World.

Black Philadelphians insisted that those Atlantic revolutions had to reckon with enslavement—the cry of liberty rang hollow if new republics were built on the back of forced labor. Finding allies, however, did not prove easy; abolitionism was never more than a minority sentiment among white people in the eighteenth century. That said, some of the region’s Quakers, African Americans, and other friends of liberty raised their voices in favor of ending enslavement and emancipating enslaved people. Connections to the Caribbean and Europe shaped antislavery activism in the Delaware Valley. An extraordinary individual named Benjamin Lay, a Quaker immigrant, became one of the region’s earliest abolitionists. Born in England the same year as Philadelphia’s founding, Lay spent years traversing the Atlantic as a sailor, left for Barbados, and from there migrated to Philadelphia. Lay’s abolitionism sprang from his ardent Quaker faith, as well as his experiences in Barbados, where he witnessed enslavement’s brutality firsthand. While in Barbados, Lay and his wife Sarah held meetings at their house and served meals to enslaved people, which infuriated white slaveholders. After he and Sarah relocated to Philadelphia, Lay tried to convince fellow Quakers in the region to emancipate enslaved people. While some Friends had rejected enslavement before Lay’s arrival, his activism led to his disownment, and he retreated to a cave he converted into a cottage in Abington, Pennsylvania. From there Lay continued to urge the region’s Friends to acknowledge Atlantic enslavement as apostasy. By the end of his life more Quaker voices in the region had begun to proclaim the abolitionism gospel, including the New Jersey merchant John Woolman, a member of the Chesterfield Friends Meeting, who died in Britain on an antislavery mission, and the French-born religious refugee Anthony Benezet, who played an important role in founding the Society for the Relief of Free Negroes Unlawfully Held in Bondage in 1775. The first abolition society in the Americas, it was later reorganized as the Pennsylvania Society for Promoting the Abolition of Slavery and for the Relief of Free Negroes Unlawfully Held in Bondage (usually referred to as the Pennsylvania Abolition Society) in 1789.

The AME Church Goes Global

In the decades that followed, Black abolitionists in Philadelphia built institutions and cultivated connections that reached across the Atlantic. By doing so they recognized that the struggle against enslavement in the United States was part of a wider battle for rights that extended to Europe, the Caribbean, and Africa. Richard Allen, building on his efforts in establishing Philadelphia’s Free African Society in 1787 and Mother Bethel Church in 1794, founded the African Methodist Episcopal Church in 1816 and became the church’s first bishop. AME churches subsequently sprang up all over the globe. By the end of the nineteenth century they had reached Bermuda, West Africa, and South Africa. An African American institution that began in Philadelphia therefore shaped the global spread of Black Christianity. Bishop Allen supported abolition, as did James Forten, a self-made sailmaker who after an initial flirtation with the idea of “colonizing” formerly enslaved Americans in Africa or Haiti became a fierce opponent of such schemes and an ardent advocate of an immediate end to enslavement. But the Atlantic connections of Philadelphia’s Black abolitionists are perhaps most evident in the career of Robert Purvis. Born free in Charleston, South Carolina, to parents of British, Moroccan, and Jewish roots, Purvis migrated to Philadelphia, where he helped found the American Anti-Slavery Society. Like many of his fellow abolitionists, Purvis sought to rally support in the United Kingdom, which had put enslavement on the path to extinction in its own colonies, and he traveled back and forth across the Atlantic Ocean on fundraising missions while corresponding with prominent British figures in the antislavery movement. When, on August 1, 1842, Black abolitionists marched through the southern wards of the city to mark the eighth anniversary of abolition across the British empire, a rampaging white mob threatened to burn down Purvis’s house.

The Lombard Street Riot of 1842, as it became known, proved just one of a series of riots that pitted rival immigrant and racial groups against one another in the “turbulent era” of the 1830s and 1840s. Tensions over religion, enslavement, and politics that reached across the Atlantic Ocean played out on the streets of Philadelphia. Immigration from Europe continued in the decades after the Revolution, with British, Germans, and Irish (especially after the beginning of the Potato Famine in the 1840s) the most heavily represented. Old World experiences shaped their politics. British Chartists, veterans of the struggle for the vote in the United Kingdom, welcomed the political rights denied to them in their country of origin. Irish Catholics gravitated toward the Democratic Party, in part due to the hostility of prominent Democrats like Andrew Jackson toward Britain. Indeed, the frequency with which Irish Catholics participated in anti-abolitionist violence owed something to their equation of abolitionism with support for the British crown. Germans, on the other hand, often backed the new antislavery Republican Party in the 1850s, and many of them saw the fight against enslavement as a continuation of the revolutions of 1848 in Europe. Catholic immigration in particular met a nativist backlash. The Philadelphia Nativist Riots of 1844, which saw the county placed under martial law, sprang from rumors that Irish newcomers wanted to replace the Protestant King James Bible in the city’s public schools. Philadelphia became a battleground in a conflict that stretched back to the English colonization of Ireland and break with Rome.

Movement across the ocean brought epidemics as well as people. Diseases rarely remained within the borders of one country; they spread rapidly across an increasingly connected world. Philadelphia’s status as an Atlantic port increased its vulnerability. A yellow fever epidemic in 1793, possibly carried on ships transporting French enslavers fleeing the Haitian Revolution, killed at least five thousand Philadelphians and sent tens of thousands fleeing from the city. Yellow fever recurred on a less destructive scale for decades. After the epidemic in 1793, the city decided to build new waterworks and engaged British-born architect Benjamin Latrobe to design them. Latrobe built the waterworks in a neoclassical style that evoked Athens. Cholera too crossed the Atlantic and caused epidemics in 1832, 1849, and 1866. By the late nineteenth century, Philadelphia’s sanitarians were learning from the hygiene measures that had begun to control such diseases in Europe.

The Arts and Sciences Flourish

Such exchange of knowledge had long been a feature of the region. The arts and sciences flourished in eighteenth- and nineteenth-century Philadelphia. Benjamin Franklin and John Bartram’s establishment of the American Philosophical Society in 1743 marked the first of many efforts for Philadelphians to demonstrate leadership in the arts and sciences. Philadelphia was the first city to lay claim to the mantle of the “Athens of America,” although some people later argued that Boston also deserved the title. The Academy of Natural Sciences of Philadelphia was founded in 1812, in part to impel the creation and diffusion of knowledge about the sciences and in part to place science in the United States on a par with its status in Europe. While Atlantic World rivalries proved important, the flourishing of the arts and sciences in Philadelphia also sprang from cultural exchange and connection, with leaders in fields as diverse as medicine (Benjamin Rush), botany (John Bartram), and history (Henry Charles Lea) all maintaining close links through either education or correspondence to their European counterparts. The French, in particular, had a powerful influence on the city, not least through the career of the merchant Stephen Girard, an immigrant who became one of the richest men in the United States and left most of his estate to his adopted city. Such figures cultivated and affirmed Atlantic World relationships.

If Philadelphia’s intellectual connections to the Atlantic remained a constant across the eighteenth and nineteenth centuries, the region’s significance to the transoceanic economy eventually started to wane in the 1800s. In contrast to Washington, D.C., which foreign observers and even many people in the U.S. derided as a miasmic swamp or a sleepy, provincial village, Philadelphia remained an Atlantic financial hub well into the 1830s. The Second Bank of the United States, based on Chestnut Street and boasting a federal charter from its foundation in 1816 to 1836, maintained transatlantic financial ties between the U.S. and Europe, particularly Great Britain. Its demise at the hands of President Jackson strained those relations, which suffered further when Pennsylvania defaulted on its debt payments to European creditors in 1842, prompting the English Lake poet (and out of pocket “surly creditor”) William Wordsworth to rail against the commonwealth’s “degenerate Men.” Furthermore, Philadelphia lost ground to New York City as an Atlantic port, as the Erie Canal (among other factors) fueled Manhattan’s ascent as the financial capital of the United States. The source of Greater Philadelphia’s wealth shifted from commerce to manufacturing, as the Athens of America transformed into the workshop of the world, which increased local support for high protective tariffs to protect home industry. These higher tariffs, however, made it harder for the city to cultivate European markets. Some Philadelphians nevertheless found overseas clients. Joseph Harrison Jr., for example, built locomotives for Russia and Czar Nicholas I awarded him a gold medal for completing the St. Petersburg-Moscow Railway. After his return to Philadelphia, Harrison amassed an impressive art collection, which he displayed at his mansion off Rittenhouse Square. Harrison, like some of his contemporaries, remained connected to the Atlantic World and prioritized connections and cultural exchange.

Philadelphia’s reputation as an Atlantic center of politics, finance, and commerce may have declined over the course of the nineteenth century but its links to its nearest ocean persisted in other respects. Immigration, which had slowed during the Civil War, accelerated again in the decades that followed. These arrivals increasingly came from eastern and southern Europe— especially Italy—rather than the western and northern reaches of the continent. Their children and grandchildren then often made the Atlantic crossing in reverse to fight in that continent’s wars. U.S. intervention in European conflict left a marked impact on the region’s economy and society. World War I and World War II stimulated ship production along the Delaware. During the latter, the Philadelphia Navy Yard employed over fifty thousand workers, whose labor made Philadelphia a vital part of the “Arsenal of Democracy.” Europe and Africa continued to exert an influence in art, design, and politics, too. Jacques-Henri-Auguste Gréber, a French landscape architect, designed and built the Benjamin Franklin Parkway. Marcus Garvey, the founder of the Universal Negro Improvement Association and a proponent of Pan-Africanism, had a following in Philadelphia. Garvey is not the only example of Philadelphia’s connections to Africa. After the loosening of federal restrictions on immigration in the 1960s, Ethiopians, Ghanaians, Liberians, and Nigerians were prominently represented in the new African diaspora of the late twentieth and early twenty-first centuries to Philadelphia.

Bonds of Culture Persist

Philadelphia’s Atlantic connections remained evident in spaces and civic life of the twenty-first century region. The Irish Memorial near Penn’s Landing, dedicated in 2003, sought to remind visitors about the migrants who built the city. The Mummers Parade could trace its roots back to older immigrant traditions from England, Germany, and Sweden. Annual Columbus Day celebrations testified to both the strength of Italian-American pride and the contested legacy of European colonization. Founders of the ODUNDE Festival, held the second Sunday in June, sought to celebrate the history and heritage of African peoples around the globe and created one of the longest-running and largest African American street festivals in the United States. Philadelphia’s historical connections to the Atlantic—forged in cultural exchange, revolutionary conflict, and the movement of peoples and revolutionary ideas—helped make the twenty-first century city a mecca for tourists. Yet such connections have sometimes underpinned a resurgent nativist politics that echoed an earlier era, as some residents used the region’s European cultural heritage to question the place of new immigrants from the Americas and Asia in the city. Philadelphia connections by the twenty-first century were global rather than primarily Atlantic. But the ocean the Delaware River empties into made the city a political and economic hub and the links it enabled remained lodged in civic memory.

Evan C. Rothera is Assistant Professor of History at Sam Houston State University. He is author of Civil Wars and Reconstructions in the Americas: The United States, Mexico, and Argentina, 1860–1880 (Baton Rouge: Louisiana State University Press, 2022) and coeditor, with Brian Matthew Jordan, of The War Went On: Reconsidering the Lives of Civil War Veterans (Baton Rouge: Louisiana State University Press, 2020). (Author information current at time of publication).

The Philadelphia region’s history as a botanical paradise and center of discovery began in the eighteenth century with the work of individual collectors and enthusiasts such as John Bartram (1699–1777), who used his home at Bartram’s Garden to cultivate and sell native plants to an international group of botanists and collectors, including Peter Collinson (1694–1768), Sir Hans Sloane (1660–1753), and Carl Linnaeus (1707–78). Linnaeus even named a variety of moss after Bartram in recognition of his botanical efforts. Bartram introduced as many as two hundred North American plant species into Europe, including the magnolia, mountain laurel, azalea, and rhododendron, and by the nineteenth century the botanic collection at Bartram’s Garden was the most extensive and varied collection of North American plants in the world.

Another eighteenth-century botanist operating in Philadelphia was Bartram’s neighbor, William Hamilton (1745–1813), who turned his country estate on the west bank of the Schuylkill River, The Woodlands, into a botanical paradise with a collection of native and exotic plants said to number ten thousand. The Woodlands and Bartram’s Garden drew plant enthusiasts of all kinds to Philadelphia, from medical students studying botany and materia medica at the University of Pennsylvania to such international luminaries as André Michaux (1746–1802), Alexander von Humboldt (1769–1859), and Peter Kalm (1716–79).

Hamilton, John Bartram’s son William (1739–1823), and other area botanists ensured that later generations of botanists would continue to make their mark in the science by establishing Philadelphia as a training ground: Hamilton employed several gardeners who went on to international careers, such as nurseryman John Lyon (1765–1814) and botanist Frederick Pursh (1774–1820). Benjamin Smith Barton (1766–1815), professor of botany and materia medica at the University of Pennsylvania, sent his student and protégé Thomas Nuttall (1786–1859) to both The Woodlands and Bartram’s Garden for training.

Philadelphia continued to dominate the botanical scene in the nineteenth century. When, as president, Thomas Jefferson (1743–1826) sought to expand the sciences on a national level, he sent Meriwether Lewis (1774–1809) to study with Barton, Hamilton, and William Bartram before he headed west to explore the recently acquired lands of the Louisiana Purchase. As there was yet no national botanic garden or arboretum, both Jefferson and John Adams (1735–1826) saw Bartram’s Garden as the appropriate substitute.

Botanical practice underwent a number of changes in the nineteenth century, both in Philadelphia and farther afield. As the century wore on, reliance on individual botanists gave way to various new institutions focused around the promotion and propagation of scientific discovery. The American Philosophical Society begun by Benjamin Franklin (1706–90) had long been a promoter of enterprising individuals working to advance understanding of science, medicine, and literature, as had other, more narrowly focused Philadelphia institutions. The Philadelphia Society for Promoting Agriculture, the oldest agricultural society in the United States, had been sponsoring scientific farming experiments and developments since 1785 and included among its early members Benjamin Franklin, George Washington (1732–99), and George Logan (1753–1821), a politician and gentleman farmer whom Thomas Jefferson considered the best farmer in Pennsylvania. However, it was not until 1812, when the Academy of Natural Sciences was founded, that Philadelphia—and the entire Western Hemisphere—had an institution specifically and explicitly devoted to the study of the “natural sciences.”

The Academy of Natural Sciences promoted botanists and other scientists through the publication and dissemination of their work. It provided an alternative for young researchers who had plenty of ambition but lacked a wealthy elite patron or an independent income that would allow them to pursue botany as more than a hobby. The academy, which sponsored public lectures on botany for women beginning in 1814, popularized the discipline and made it accessible. It also funded increasingly ambitious collecting expeditions to the Arctic, Central America, Africa, and Asia. Other institutions soon followed, including the Pennsylvania Horticultural Society, founded in 1827, which brought together botanical and horticultural enthusiasts; the Wagner Free Institute of Science, formally established in 1855, with the goal of bringing free science education to the wider public; and the Philadelphia Botanical Club (1891), which counted among its members several prominent naturalists such as Thomas Meehan (1826–1901) and John Harshberger (1869–1929). Institutional support of botanical and other scientific activities in Philadelphia contributed to the founding of the first college of pharmacy in North America in 1821, the Philadelphia College of Pharmacy, which drew broadly on Philadelphia’s reputation as a center for botanical and medical science.

The later nineteenth and twentieth centuries saw even more expansion in botanical activities in Philadelphia and beyond as interest in new areas of study including conservation, evolutionary biology, and ecology grew along with a devotion to a more general public audience. In 1907 Pierre S. DuPont (1870–1954) established Longwood Gardens in Chester County as a botanical conservation and horticultural sanctuary outside the city, which grew into an extensive landscape devoted to public education in horticulture and ecological conservation. Other institutions furthered interest in botanical activities by capitalizing on the public’s interest in horticultural displays revived by the 1876 Centennial Exhibition and the construction of Horticultural Hall. A century later, the modern Horticultural Center in Fairmount Park replaced Horticultural Hall and brought visitors to the display and demonstration gardens all year round. The Pennsylvania Horticultural Society built on this interest with its annual Philadelphia Flower Show (first established in 1829), which drew an estimated 250,000 visitors annually by the early twenty-first century, and its locally targeted efforts coordinated through the Philly Green program (established in 1974).

In the later twentieth century, institutional support for botanical activities expanded through consolidation as Philadelphia-area universities formed partnerships with other local institutions including the Morris Arboretum (University of Pennsylvania) and the Academy of Natural Sciences (Drexel University) to further ecological, horticultural, and biological research across multiple platforms. Botanical activities, consolidated under the larger umbrella of biology and life science departments and medical research programs, continued to expand our understanding of the natural world.

The story of botany in the Philadelphia region is a story of individuals and institutions that, from the eighteenth century forward, established Philadelphia as a city of botanical discovery and abundance as well as a destination for botanical enthusiasts from around the world.

Sarah Chesney is a historical archaeologist who earned her Ph.D. in anthropology from the College of William and Mary in 2014. She has worked on several landscape archaeology projects in Philadelphia exploring the intersection of archaeology, landscape, and early modern science. Her publications include “The Root of the Matter: Searching for William Hamilton’s Greenhouse at The Woodlands Estate, Philadelphia, Pennsylvania,” in Historical Archaeology of the Delaware Valley, 1600–1850, edited by Richard F. Veit and David G. Orr (University of Tennessee Press, 2014). (Author information current at time of publication.)

In Philadelphia, John Harrison (1773–1833) built the first chemical plant in the United States in 1793. His plant on Green Street, west of Third, produced sulfuric acid using a lead chamber process, originally developed in Europe. Sulfuric acid was the first chemical produced on an industrial scale, leading to its widespread use. In 1802, the French immigrant family led by Eleuthère Irénée duPont  (1771–1834) founded the DuPont Company, which manufactured gunpowder, a mixture of charcoal, sulfur, and saltpeter, on the Brandywine River a few miles northwest of Wilmington, Delaware. Several years later, in 1804, Samuel Wetherill (1736–1816) began to make white lead pigment for paint near Harrison’s plant. When the War of 1812 disrupted trade and cut off European supplies of sulfuric acid, Wetherill began to make his own.

Soap and Sulfuric Acid

The regional chemical industry grew along with the local economy. By the start of the War of 1812, Philadelphia had twenty-eight soap and candle works, eighteen distilleries, fourteen glue factories, ten sugar refineries, seven paper mills, and six drug-making concerns. By 1830 Charles Lennig (1809–91) operated the largest sulfuric acid plant in America, located in Bridesburg. He diversified into other chemicals, and by 1859 his plant was one of the most important chemical operations in the United States. During the Civil War, the DuPont Company prospered by selling gunpowder to the Union. Later, the company diversified into the new high explosive, dynamite, and military smokeless powder. DuPont was one of 105 local chemical manufacturers to mount exhibits at the 1876 Centennial Exhibition in Philadelphia.

In the twentieth century, the DuPont Company and Rohm and Haas emerged as the two most important chemical enterprises in the Philadelphia area. Rohm and Haas became a Philadelphia company in 1909 when Dr. Otto Haas (1872–1960) arrived to sell a leather tanning chemical, Oropon, which had been developed by his partner Otto Rohm (1876–1939) in Germany. After World War I, Rohm and Haas began making chemicals for Philadelphia’s leather and textile industries. In 1920, it acquired the Charles Lennig Company. In the 1930s, company researchers developed a lightweight clear acrylic polymer that was trademarked Plexiglas. Plexiglas was widely used for windows in airplanes during World War II. After the war the company continued to develop important products from acrylic polymers, such as water-based paints. In the postwar decades, Rohm and Haas became a large and profitable manufacturer of specialty chemicals.

DuPont Faces Antitrust Action

By 1912, DuPont had grown so large that the U.S. government had filed an antitrust suit, which forced the company to spin off parts of its explosives business to form two new companies, Hercules and Atlas, named after popular brands of dynamite. These companies later became diversified chemical manufacturers, which were bought by other chemical companies in the second half of the twentieth century. DuPont’s assets grew tremendously during World War I, when the company supplied the Allies and the United States with explosives. DuPont used its newfound wealth to diversify into chemical manufacture, principally by buying other firms, such as the venerable Harrison Brothers Company in 1917, which by this time made chemicals and paints at Gray’s Ferry. During the war, DuPont began a major research initiative to manufacture the dyes that the Germans had supplied before the war. To make dyes, the company built a large plant on the Delaware River at Deepwater Point, New Jersey (just north of the Delaware Memorial Bridge).

After the war DuPont continued to diversify into rayon fibers, cellophane films, and plastics. Having been one of the first American companies to establish research laboratories (early in the twentieth century), DuPont called upon its chemists to improve these products, but they soon began to invent new ones. In the 1930s researchers began a decades-long investigation of polymers (long-chain) molecules that produced, among many iconic products, neoprene synthetic rubber, nylon, Teflon polymers, Lycra spandex, Tyvek spun-bonded fabric, and Kevlar fibers. These inventions helped to make DuPont an extremely prosperous company, a bulwark of the Delaware Valley economy, employing tens of thousands of people in several local plants, but mainly in management, research, and engineering.

The Philadelphia area also was well-represented at midcentury by two industries closely related to chemicals: oil refining and pharmaceuticals. There were five large refineries in the Delaware Valley, making it the second only to Houston, Texas, in output, and the city also hosted four major drug manufacturers.

Late Twentieth-Century Slowdown

Beginning in the 1980s, the chemical industry generally began to experience a decline in innovation, slowing growth, and shrinking profits. Rohm and Haas’s performance, following these trends, deteriorated significantly. In response, it sold off its Plexiglas business and acquired a company that made chemicals for the semiconductor industry. In 2008, the Michigan-based Dow Chemical acquired Rohm and Haas. DuPont survived by shifting its focus to pesticides and seeds. However, competition in this field led the company to a merger effort with Dow Chemical, its longtime competitor, in 2015. By the early decades of the twenty-first century, the chemical industry had been radically reorganized through numerous mergers and acquisitions.

Chemical production began in Philadelphia in the late eighteenth century to serve nearby manufacturers in what soon would become one of America’s major industrial cities. By the middle of the nineteenth century, Delaware Valley companies, notably DuPont, were taking advantage of railroad transportation to serve larger markets. In the twentieth century, the regional chemical industry served national and international markets, expanding to become a significant contributor to the local economy. In the last quarter of the century, however, the chemical industry globally matured, leading to a decline of its importance locally.

John Kenly Smith Jr. teaches history at Lehigh University. He specializes in the history of technology and is coauthor with David A. Hounshell of Science and Corporate Strategy: DuPont R&D, 1902–1980. (Author information current at time of publication.)

Philadelphians used chemistry to enhance manufacturing, household practice, and artisan trades, mixing scholarly with practical aims from the outset. Furthermore, chemistry’s relationship to other scientific disciplines, including botany, geology, and medicine, made Philadelphians particularly keen to promote and diffuse chemical knowledge. Encouraged by widespread interest in chemistry between the eighteenth and twenty-first centuries, a number of cutting-edge chemical societies, research laboratories, and educational institutions dedicated to the advancement of the science made their home in the region.

Eighteenth-century Philadelphians recognized chemistry’s importance to various trades. Chemists prepared and sold chemical substances, functioning much like a pharmacist. Although chemists’ primary relationship was to the medical profession, they also supplied chemicals used in various arts and industries. Artists, printers, and clerks, for example, often required colored inks and paints; these could be made from pigments and compounds available at the local chemist’s shop. This relationship between chemist and community, along with prevailing popular narratives about the importance of “useful knowledge,” helped to foster a belief that chemistry could improve daily life for individuals, the locality, and, after the American Revolution, for the nation. Philadelphians readily embraced the concept that practical application of chemistry could improve one’s labor and, consequently, sought to expand access to chemical education.

Women were at times the beneficiaries of these arguments, insofar as chemistry could be justified as important to their labor. Philadelphia’s flagship female academy, the Young Ladies’ Academy (founded 1787), offered chemistry lessons in relation to household management. An early syllabus suggests that female students learned how to improve cooking, washing, and dyeing by understanding the chemistry behind these tasks. Popular publications echoed the agenda of the academy. For example, in 1789–90, John Penington (1768–93) wrote a number of essays, first for the Columbian Magazine, and later in a treatise called Chemical and Economical Essays, showing chemistry’s usefulness to pottery, soap making, painting, and other arts practiced by women.

Multiple Scientific Institutions

Given Philadelphia’s widespread interest in chemistry education, it is not surprising that the city became home to several learned societies that championed chemical research and helped to professionalize the discipline. Broadly focused scientific institutions, such as the American Philosophical Society (founded 1743) and the Franklin Institute (founded 1824), facilitated the diffusion of chemical knowledge for both practical and scholarly matters. The first dedicated chemical society in America, predating the Chemical Society of London (1841) by nearly fifty years, was the short-lived Philadelphia Chemical Society, founded in 1792. Prominent members included Benjamin Franklin’s grandson, William Bache (1773–1820), who served as president of the society in 1794; James Woodhouse (1770–1809), chair of chemistry at the University of Pennsylvania; and Joseph Priestley (1733–1804), best known for isolating and identifying oxygen gas. Priestley had fled England in the 1790s for religious and political reasons, settling for a time in Philadelphia. The society extended honorary membership to the Scottish national Elizabeth Fulhame (active between 1780 and 1794), who experimented in synthesizing cloths of metal and first described the chemical process of catalysis, the acceleration of a chemical reaction. Late eighteenth-century societies participated in debates over phlogiston theory. Practitioners hypothesized the existence of a firelike element released during combustion and evaluated chemical reactions in terms of adding or subtracting phlogiston. Priestley’s discoveries and the work of Antoine Lavoisier (1743–94) in France, helped to disprove phlogiston theory by the 1790s. Early nineteenth-century societies, including the Columbian Chemical Society (founded 1811) became increasingly engaged with atomic theory, which states that all matter is composed of atoms.

Chemical societies offered individuals the opportunity to share their research with a knowledgeable audience, allowing them to refine their ideas and promote their discoveries, ultimately furthering their careers. In 1801, the Philadelphia Chemical Society sought to improve the efficiency of blowpipes, a tool that amplifies the heat of a flame in chemical experiments. Robert Hare (1781-1858), a corresponding member of the society, demonstrated a solution to the problem posed by the society of increasing the concentration of heat available for chemical experiments. Previously experimenters used blowpipes powered by their own lungs to increase the supply of air available to affect the combustion of various materials under study. He developed an oxyhydrogen blowtorch for this purpose, which he recounted in his Memoir on the Supply and Application of the Blow-Pipe (1802). Shortly after, in 1803, the American Philosophical Society elected Hare a member, giving him a wider audience. Other instruments developed by Hare include an improved eudiometer (c. 1820s), an instrument used for gas analysis; a calorimeter (c. 1819), a tool for measuring the heat of chemical reactions; a litrameter (c. 1819), an instrument that determined the specific gravity of fluids; and a galvanic deflagrator, an instrument that uses powerful electrical discharges to create high temperatures. In 1818, Hare became the chair of chemistry at the University of Pennsylvania, a position he held until 1847. In 1826, Hare published a descriptive account of the various chemical apparatuses used in his chemistry classes, many of which were his own design, to supplement his lectures.

Generally, institutions of higher education continued to underscore the importance of chemistry to various scientific professions. Some of these institutions, such as the Woman’s Medical College of Pennsylvania (founded 1850) and Polytechnic College of Pennsylvania (founded 1853), an engineering school, offered chemistry to women, and in the case of the medical college, to women of color. Rachel Littler Bodley (1831–88) traveled from Ohio to Philadelphia in 1860 to pursue educational opportunities at both schools. By 1865 Bodley became chair of chemistry and toxicology at the Woman’s Medical College and offered popular lectures at the Franklin Institute regarding applications of chemistry to household management. Bodley taught chemistry while it was undergoing significant change; it was only in 1869 that Russian chemist Dmitri Mendeleev (1834–1907) put forth a relatively modern version of the periodic table of elements based on atomic weight. She was also instrumental in organizing a group of prominent chemists who met at Joseph Priestley’s gravesite in Northumberland, Pennsylvania, to commemorate the centennial of his discovery of oxygen in 1774. Excitement generated by this meeting contributed to organization of the American Chemical Society in 1876, of which Bodley was a charter member. That same year, Edgar Fahs Smith (1854–1928) became an assistant professor of chemistry at the University of Pennsylvania. Though Smith briefly left to work at Muhlenberg College (1881–88), by 1893 he had assumed directorship of the chemistry laboratory, allowing women to work alongside male students. Because of his liberal policies, the first two women admitted to the University of Pennsylvania, Gertrude Klein Pierce (1859–1953) and Anna Lockhart Flanigen (1852–1928), came to study chemistry.

Discoveries Outside the Academy

Outside the academy, manufacturers fostered a number of important chemical discoveries. DuPont, located in nearby Wilmington, was responsible for some of the more significant twentieth-century discoveries, though the company had a long history of chemical innovation. Founded in 1802 by French chemist Éleuthère Irénée du Pont (1771–1834) to produce gunpowder, DuPont laboratories became increasingly focused on the discovery and production of new polymers in the 1920s and 1930s. Wallace Carothers (1896–1937), hired in 1928, was instrumental in the development of neoprene in 1930 and nylon in 1935. DuPont produced Teflon, commonly used as a nonstick coating in cookware, in 1938. Joseph Shivers (1920–2014), who began working for DuPont in 1946, produced the synthetic fiber known as Lycra in 1958. In 1909, Otto Röhm (1876–1939) and Otto Haas (1872–1960) moved from Esslingen, Germany, to Philadelphia and founded the pseudonymous chemical company, Röhm and Haas. The company developed Orophon, a synthetic chemical that made the leather tanning process more hygienic, and were the first to bring acrylic glass (as Plexiglas) to market in 1933.

Similar breakthroughs occurred within the pharmaceutical industry, launching local Philadelphia chemists to financial success and philanthropic giving. In 1899, Albert C. Barnes (1872–1951), along with Hermann Hille (1871–1962), developed Argyrol, an antiseptic of silver nitrite that successfully treated gonorrhea. Profits from Argyrol enabled Barnes to buy a number of important works of art, which today are kept at the Barnes Foundation. McNeil Laboratories, founded by Robert McNeil (1856–1933) in 1879, started as a drug store in Kensington and became a full-fledged research facility by 1933. McNeil’s grandson, Robert Lincoln McNeil Jr. (1915–2010), a graduate of Philadelphia College of Pharmacy and Science, began to develop the chemical acetaminophen for use as a painkiller. The company eventually was able to market Tylenol after it was approved by the Food and Drug Administration in 1955.

Philadelphia’s chemistry-rich history made it a natural home for an institution dedicated to studying the history of the science. In 1982, the University of Pennsylvania and the American Chemical Society jointly sponsored the Center for the History of Chemistry. With the additional support of the American Institute of Chemical Engineers, the center gained national nonprofit status by 1987 and was renamed the Chemical Heritage Foundation in 1992. The Chemical Heritage Foundation sought to provide resources to researchers interested in chemistry’s societal impact. In the early twenty-first century, the institute offered several scholarly fellowships and maintained a library and museum. Its collections reflected an interest in chemistry’s relationship to manufacturing, but also manufacturing’s relationship to chemistry, a collecting interest most suited to Philadelphia’s scientific past. The region’s historical emphasis on practical applications of chemistry frequently shaped the nature of its contributions and its practitioners.

Jessica Linker is a doctoral candidate at the University of Connecticut, Storrs, and the recipient of fellowships from a number of Philadelphia-area institutions, including the Library Company of Philadelphia, the American Philosophical Society, and the McNeil Center for Early American Studies. Her work focuses on American women and scientific practice between 1720 and 1860. (Author information current at time of publication.)

Before 1750 the majority of clockmakers in the colonies were trained in England. However, Pennsylvania in particular became noted for the influence of German designs on its clock production. Although English Quakers dominated Philadelphia, William Penn’s “holy experiment” attracted tens of thousands of settlers from Germany, Switzerland, and Ireland. These immigrants included many skilled artisans from northern Europe, including clockmakers, making Pennsylvania a prime site for producing high-quality clocks.

One of the earliest clocks to make its way to the Philadelphia region was the “Dial of Ahaz,” named after the King of Judah who supposedly invented the sundial in the eighth century B.C.E. The Ahaz sundial was made by Christopher Schissler (ca. 1531-1608) in Germany in 1578 and arrived some time before 1700 with a mystical religious group known as the Pietists or the Hermits of the Ridge. This group, dissatisfied with Protestant and Catholic ritual and led by Johannes Kelpius (1667-1708), came to Pennsylvania in 1694 and settled in Germantown. The group’s interests in mathematics and the astronomy used to calculate the time of the millennium made them prime candidates for clockmaking.

The Eminent Christopher Witt

An entire school of clockmakers trained under another Pietist, Christopher Witt (1675-1765), who arrived in Germantown in 1704 and began making clocks as early as 1706. It is believed that Witt gave the Dial of Ahaz to Benjamin Franklin as a gift. Witt went on to apprentice another important clockmaker in the German tradition, Christopher Sauer (1695-1758). A brass dial, tall-case clock made by Sauer around 1735 became the earliest American-made clock in the collections of the Library Company of Philadelphia.

Pennsylvania clock production was set apart from New England by the high quality and individual construction of the tall case clock, a design that consisted of parts often made separately in England, France, and America. These included a case, dial, and mechanism and required collaborative work among cabinetmakers, iron founders, engravers, braziers, ornamental painters, and mathematicians. The weight-and-pendulum design housed in a tall case became known as a “grandfather clock,” the name of which can be traced to a Philadelphia songwriter. In 1876, Henry Clay Work (1832-84) wrote these lyrics: “My grandfather’s clock was too tall for the shelf so it stood twenty years on the floor.” In Pennsylvania, clocks were a symbol of family and stability, often passed down as important heirlooms through generations.

Businesses and government relied on clocks to facilitate meeting times and to regulate working hours. As business and trade increased, the variability of watches necessitated the construction of a public clock. The first of these in Philadelphia was housed in the old courthouse built in 1710 at Market and Second Streets. Made by English clockmaker Peter Stretch (1670-1746), the device told time aurally by ringing a bell.

As the city grew and the center of town shifted farther west, Philadelphia needed a new public clock. According to legend, Benjamin Franklin asked his friend Edward Duffield to make a clock for public display after growing tired of being constantly stopped by workmen on the street wishing to know the time. At this time, personal watches were still a luxury item. Duffield’s clock hung outside his shop at Second and Arch Streets from the 1740s until the Revolutionary War. In 1753, a new public clock was installed at the Pennsylvania State House (Independence Hall). The clock faces on the building’s east and west gable ends were made by Peter Stretch’s son, Thomas (1697-1765). It was not until 1828 that a clock designed and constructed by Isaiah Lukens (1779-1846) and Joseph Saxton (1799-1873) was installed in a new tower, built to replace the long-demolished original.

David Rittenhouse

When David Rittenhouse moved from Germantown to Philadelphia in 1770, clock making continued to be his chief source of income. Rittenhouse made approximately seventy-five clocks in his lifetime and, in a distinctly Pennsylvania tradition, each was unique. Thomas Jefferson described one Rittenhouse orrery, a mechanical model of the solar system, as “a machine far surpassing in ingenuity of contrivance, accuracy, and utility, anything of the kind ever before constructed. …He has indeed made a world, but by imitation approached nearer its Maker than many man who has lived from the creation to this day.” The orrery’s clockwork mechanism represented a view of an orderly, clockwork universe, something essential to the values and ideals of the new republic.

By the 1820s clocks ceased to be a luxury item and became so common that they were considered just another piece of household furniture. Around 1835, the Pennsylvania tall clock began to be supplanted by the cheaper, mass-produced New England shelf clock. Consequently, the definition of “clockmaker” began to shift. Various individuals who had no part in the final construction of a clock and who had no knowledge of its mechanisms could separately manufacture individual parts. Under this division of labor, a clockmaker referred primarily to a tradesman who polished a clock’s teeth and steel parts and adjusted the mechanism to maintain accurate timekeeping.

While mass production of clocks flourished in New England, Philadelphia, New Jersey, and Delaware remained known for a tradition of artisanal clocks of the highest quality and individual character. In Delaware, between 1740 and 1840, forty-five clock and cabinetmakers had establishments in Wilmington alone. In New Jersey, notable clockmakers included Isaac Brokaw (1746-1826) in Elizabethtown and Aaron Dodd Crane (1804-1860) in Newark. Brokaw was known for his handcrafted clock pieces, down to the hand hammering of brass dials. Crane published several patents for improving clock mechanisms and the market for his clocks extended as far as New York and Boston. These tall case clocks illustrated and reflected the diverse and collaborate nature of the wider Philadelphia region’s artisanal and scientific communities.

Influence of Mass Production

With the proliferations of mass-produced clocks and smaller, inexpensive watches at the beginning of the twentieth century, artisanal clock production slowed. However, public clocks continued to play an important role in shaping the landscape of Philadelphia. The synchronization of time became necessary to coordinate and regularize the flow of rail travel, leading to the 1893 implementation of Standard Railway Time across the United States. Public clocks in Philadelphia could be seen at its many transportation hubs, including the Pennsylvania Railroad’s Broad Street Station built in 1881. In 1892, a twenty-one-foot Victorian-style clock stood at Broad and Chestnut Streets in front of the ticket office for the Reading and Baltimore & Ohio Railroads. After being moved to Twelfth and Chestnut Streets in 1901, the timepiece was nicknamed “Lover’s Clock” since it was used as a meeting place for couples on dates.

Public clocks dramatically shaped the iconography of Philadelphia’s skyline. The city’s most iconic timepiece, the fifty-ton clock at City Hall, 362 feet above Broad and Market Streets, was the largest and highest in the world when installed and put to service at midnight December 31, 1898. Time could be determined from approximately a mile away, allowing citizens to adjust their home clocks to official Philadelphia time. The 150 incandescent light bulbs that illuminated the clock were originally bright white. By the 1940s, the plate glass of the clock faces were yellowed by sulfurous coal smoke, producing the now-iconic amber glow of the City Hall clock. In 1963, the city officially changed the cleaned bulbs to a tinted yellow color, creating the most recognizable fixture of the Philadelphia skyline. Several blocks north on Broad Street, the four-faced clock atop the Inquirer Building, the tallest building north of City Hall when constructed in 1924, could be seen from miles away. Even after cheap wristwatches and cell phones replaced the need for the manufacture of clocks, the public clocks of Philadelphia continued to define the city’s landscape and iconography.

Michelle Smiley is a Ph.D. candidate in the History of Art at Bryn Mawr College. Her dissertation considers the history of photography and its technological development in the United States. (Author information current at time of publication.)