A Provocation on the Rooftops of Saint-Omer

In the small northern French town of Saint-Omer, nestled in the province of Artois near the English Channel, a local lawyer named Charles Dominique de Vissery de Bois-Valé decided to make a bold statement in 1780. On his rooftop, he erected a massive lightning rod, an invention still novel and controversial in Europe. This was no mere practical installation; it was a deliberate act of philosophical defiance. Vissery intended his device to scorn those who still believed lightning was a manifestation of divine wrath, aligning himself instead with the emerging ideals of the Enlightenment—reason, scientific progress, and intellectual freedom.

The structure itself was both intricate and symbolic. It consisted of a gilded sword blade mounted atop a sixteen-foot iron rod. At their junction sat a weathervane shaped like a globe, adorned with emblems of lightning bolts radiating in multiple directions. The iron rod descended into a tin chimney, which featured a perforated tin plate at its base. From there, a fifty-seven-inch tin conduit ran down the adjacent wall, burying itself in the ground to safely disperse electrical charges. To Vissery, this was a monument to human ingenuity; to his neighbors, it was an alarming and dangerous eyesore.

Community Backlash and Legal Confrontation

The townspeople of Saint-Omer reacted with fear and hostility. They viewed the lightning rod not as a marvel of science but as an affront to tradition and religion, potentially inviting divine retribution upon the community. Their anxiety quickly escalated into action: they petitioned the local court, which issued an order demanding the structure’s removal. When Vissery refused to comply, the situation turned violent. Neighbors hurled stones at his home, shouting insults and curses, reflecting the deep-seated superstitions and resistance to change that characterized much of provincial Europe at the time.

The local court reaffirmed its demolition order, but Vissery remained steadfast. He appealed to the Provincial Council of Artois, the highest judicial authority in the region based in Arras. For his defense, he enlisted François Bissart, a passionate amateur scientist locally nicknamed “the Barometer” for his meteorological interests. Bissart threw himself into the case, compiling a detailed report that blended scientific argumentation with Enlightenment rhetoric. Recognizing the need for legal expertise, he shared his findings with a young, recently returned lawyer from Paris: Maximilien Robespierre.

The Ascent of a Young Advocate

Robespierre, then twenty-five years old, had just returned to Arras in 1781 after twelve years of study in Paris. He was ambitious, intellectually fervent, and deeply influenced by Enlightenment thinkers. When Bissart presented him with the case in 1783, Robespierre saw an opportunity to champion causes he held dear: reason, progress, and the defeat of obscurantism. Building on Bissart’s groundwork, he crafted a powerful defense that would not only sway the court but also mark his own emergence into public life.

Appearing before the Provincial Council in June 1783, Robespierre delivered a stirring oration. He framed the case as a pivotal moment in the struggle between enlightenment and ignorance, urging the judges to side with science and progress. “Gentlemen,” he declared, “you must defend science.” He emphasized the international significance of their decision, noting that “all of Europe is watching this case,” and that capitals from Paris to Saint Petersburg would learn of their verdict. His argument prevailed; the council ruled in Vissery’s favor, allowing the lightning rod to remain.

Emboldened by this victory, Robespierre took a step that revealed both his ambition and his reverence for the transatlantic Republic of Letters. He sent a copy of his court address to Benjamin Franklin, who was then residing in Paris as the envoy of the newly independent United States. Franklin was not only a founding father of America but also the most celebrated electrical experimenter of his age—the very inventor of the lightning rod. In a letter dated October 1, 1783, Robespierre expressed his admiration and his hope that defending Franklin’s invention would help “eradicate prejudices hindering progress” and earn “the recognition of the world’s most renowned scientist.”

Franklin’s World: Science, Diplomacy, and the Spirit of an Age

Franklin’s life in Paris during this period was a whirlwind of scientific curiosity and diplomatic triumph. On August 27, 1783, he witnessed the world’s first manned hot-air balloon flight at the Champ de Mars—the future site of the Eiffel Tower—an event that captured the public imagination and symbolized humanity’s soaring aspirations. Just days later, on September 3, he rejoiced in the signing of the Treaty of Paris, which formally ended the American Revolutionary War and recognized the sovereignty of the United States.

Franklin was fêted in France not only as a conqueror of Britain, France’s longtime rival, but also as a embodiment of Enlightenment values: a scientist, a republican, and a “man of progress.” His presence resonated with the ideals of the philosophes, who saw in him a living example of reason applied to both nature and governance. Though it is unclear if Franklin ever responded directly to Robespierre’s letter, the episode illustrates how Franklin served as an icon for an entire generation of European intellectuals eager for change.

The Republic of Letters and the Enlightenment Project

The affair of the Saint-Omer lightning rod occurred within a broader context of intellectual ferment known as the Republic of Letters. This was not a formal polity but a transnational community of thinkers, writers, and scientists who shared a commitment to reason, critique, and the dissemination of knowledge. As Voltaire aptly described it, this republic consisted of people capable of self-governance rather than enduring “despotism.” Its reach extended from Italy to Scotland, Philadelphia to Latin America, and even into Eastern Europe and South Asia, but its epicenter was undeniably France.

At the heart of this movement was a radical rethinking of authority—both political and religious. Enlightenment thinkers argued that legitimate governance derived from public consent, not divine right, and that individual freedoms were inherent rights rather than privileges granted by rulers or clerics. Denis Diderot, co-editor of the monumental Encyclopédie, captured this spirit in 1771: “The genius of our age is liberty. The first attack on superstition was violent, unbridled. Once people dared to assail religion—that most formidable barrier—nothing could stop them.”

The Encyclopédie itself, published between 1751 and 1772, stood as a testament to this project. With its 28 volumes, 71,818 articles, and 3,129 illustrations, it sought to compile all human knowledge while subtly critiquing the pillars of the old regime: absolutism and religious orthodoxy. Contributors included luminaries like Voltaire, Rousseau, and Turgot, but also lesser-known figures like Louis de Jaucourt, a Protestant scholar who wrote a quarter of the entries. For Diderot, the Encyclopédie was not just a reference work; it was an engine of revolution—intellectual, and eventually, political.

Cultural and Social Impacts: From Ideas to Action

The lightning rod trial, though a local dispute, echoed the larger cultural tensions of the era. It pitted emerging scientific rationality against entrenched religious belief, individual expression against communal tradition, and cosmopolitan ideals against provincial conservatism. Such conflicts were playing out across Europe, as educated elites increasingly embraced notions of progress, while many ordinary people remained wary of rapid change.

In France specifically, these intellectual currents had profound social implications. The critique of absolutism and clerical power, advanced in salons, books, and courtrooms alike, eroded the legitimacy of the ancien régime. Figures like Robespierre, who would later become a central figure in the French Revolution, cut their teeth on cases that blended legal argument with ideological advocacy. His defense of Vissery was a rehearsal for the larger drama to come—one in which “enlightenment” would be invoked to justify radical political transformation.

Moreover, the transatlantic exchange of ideas, exemplified by Robespierre’s letter to Franklin, helped forge a shared vocabulary of rights and liberties. American independence served as both inspiration and proof of concept for European reformers, demonstrating that republican governance was achievable. Franklin, as scientist and statesman, personified this linkage between knowledge and power, between experiment and emancipation.

Legacy and Modern Relevance

The story of the Saint-Omer lightning rod is more than a historical curiosity; it is a microcosm of the Enlightenment’s broader impact. It illustrates how abstract ideas—about nature, authority, and human potential—could ignite concrete conflicts and catalyze change. Robespierre’s successful defense not only saved a metal rod on a rooftop but also affirmed the principle that scientific progress should not be hindered by prejudice.

In the years that followed, the themes raised by the case would reverberate through the French Revolution. Robespierre, once the young lawyer arguing for reason, would become the architect of the Reign of Terror—a stark reminder that the pursuit of enlightenment could veer into new forms of absolutism. Yet, the ideal of a society guided by knowledge and reason endured, influencing subsequent movements for democracy, human rights, and scientific inquiry.

Today, the lightning rod stands as a symbol of protection and progress, but also of the tensions that accompany innovation. Modern debates over technology, climate science, and public health often echo the dynamics of 1780s Saint-Omer: between expertise and popular belief, between individual rights and communal norms, between the allure of the new and the pull of tradition. Understanding this historical episode reminds us that the path of progress is rarely smooth, and that the defense of reason requires not only intelligence but also courage.

In the end, Vissery’s rooftop device—and the controversy it sparked—encapsulates a pivotal moment when the old world began to give way to the new. It was a spark that helped ignite a revolution, both in minds and in streets, whose echoes we still hear today.