John Sullivan is a 2025-2026 Consortium Research Fellow.
My project, Fractious Knowledge: Earthquakes and Engineering between Italy and America, examines environmental engineering measures proposed and implemented after seismic disasters in the kingdoms of Guatemala and Naples in the late eighteenth century. An unlikely pairing at first blush, both realms existed under Bourbon rule during this period and participated in the dynasty’s sweeping programs of political, social, and economic reform. These governmental overhauls extended to institution-building efforts that professionalized and patronized growing cohorts of engineers, architects, and naturalists. Graduates of the Bourbons’ new academies and colleges coalesced into an interrelated class of Italo-Spanish technocrats who spanned disaster zones in Guatemala and Calabria, investigated the nature of seismicity, and supervised reconstruction.
I thus trace how a diasporic expert class, forged in the same cultural matrices, came into contact with representatives of local seismic cultures—informants, guides, laborers—endemic to peripheral regions of intense seismicity. The troves of memoranda, reports, correspondence, and testimonies that burgeoning technocracy generated document the Bourbons’ ambitious post-disaster renovation efforts and disclose the numerous instances where metropolitan expertise relied on and appropriated local knowledge and skill to achieve its ends. In the siting of new cities, the raising of grand cathedrals, and the execution of complex hydraulic engineering schemes, an understanding of how earthquake-prone environments behaved that could not be replicated through academic study compelled Bourbon officials to engage with the tacit knowhow of the mason and the carpenter. Ultimately, seismic disasters laid bare the inseparability of built structure from building site, the necessity of architectures of adaptation, and hence the reliance of accreted, urban, transoceanic imperial power on its subjects’ vernacular traditions.
During my 2025–2026 Consortium Research Fellowship, I augmented my project’s existing source base—mostly consisting of manuscript materials in Guatemalan, Italian, and Spanish archives—with a broad range of printed works treating the natural philosophy of earthquakes. I consulted these texts at the Newberry Library, the University of Oklahoma, the Huntington Library, the Smithsonian, and the University of Illinois and am in the process of shaping them into a new chapter, “Electric Earthquakes: Seismicity’s Scale in the Enlightened Atlantic.” Generally, since plate tectonics as a reigning theory of seismogenesis did not gain currency until the twentieth century, historians of science have not paid too much heed to early modern explanations of earthquakes’ cause. No major advances, like those in astronomy and physics, mark the period for glory in the annals of earthquake science. Natural philosophers, though they enjoyed squabbling over small differences, fundamentally retained Aristotle’s pneumatic understanding of seismicity, whereby tremors resulted from air currents moving through subterranean passageways. Hence, where notable earthquakes enter the historical record, Lima in 1746, Lisbon in 1755, scholarly interest focuses much more on their status as disaster events with social and political implications. Their status as physical phenomena and the principles that contemporaries invoked to explain them command relatively less attention. But despite such historical continuities and historiographical neglect, change did occur.
My Consortium research demonstrates a scalar shift, from local to global, in early modern European thinking about earthquakes that the era’s concurrent colonial and imperial expansions brought about. Europeans did not just inherit a theory of seismogenesis from Aristotle. The Athenian also bequeathed them a conception of earthquakes as specifically local in scale. They occupied interstitial zones, where different subterranean currents met and admixed, sometimes disastrously. But never, in Aristotle’s view, did seismic destruction extend farther than a couple hundred miles from a given epicenter. An earthquake’s remit was limited. As Europe’s remit expanded, however, Aristotle’s theory of localized seismicity came under increasing strain.
A clear example of how early modern globalization troubled classical understandings of earthquakes is Marcello Bonito’s Terra tremante (1691), an encyclopedic, as-yet undigitized volume that I encountered in the Cavagna Sangiuliani Collection at UIUC. A Neapolitan nobleman who survived southern Italy’s catastrophic 1688 Sannio earthquake, Bonito devoted the three subsequent years to compiling information on every seismic event recorded in world history. He committed countless hours to his enterprise in Naples’ archives and libraries, searching through rare books and obscure manuscripts, histories and newssheets, for any mention of earthly upheaval. Nine of his volume’s ten books chronologically ordered every earthquake he had found, commented on sources briefly, and excerpted them at length. The first volume faithfully repeated classical, chiefly Aristotelian, wisdom concerning earthquakes’ origins, signs, effects, and cures, as a way of orienting readers to the compendium’s subject matter.
Despite its status as a reference book pieced together out of the words of others, Terra tremante was more than the sum of its parts. By its end, as Bonito shuttled back and forth between earthquakes reported in South America, East Asia, and Europe, his mediating commentary talked in terms of individual seismic events’ outsize scales and the global interconnection of subterranean seismogenic currents. Giovanni Botero’s Relazioni universali introduced the nobleman to a 1562 earthquake in Chile that ruined the port of Concepción and coursed across 900 miles of the Pacific coast. Its reach was, according to Bonito, “strange to Philosophers,” given that it affected an area more than four times larger than what Aristotle had determined to be a seismic wave’s farthest possible extent. Examined in isolation, the spatial scale alone of this Chilean temblor made it “something truly marvelous.” It disrupted Bonito’s belief, of ancient pedigree, that earthquakes were local events.
Equally noteworthy is how Bonito discussed earthquakes that, if unremarkable when taken individually, gained significance when considered in relation to others of close temporal proximity and vast spatial distance. Shifting between reports of two different, but to Bonito’s mind possibly interrelated seismic events, he watched as “these tyrants [the movements] undertook a long journey in the same year 1640, for from Calabria they arrived in America, where, hitting the mountains of Chile, they made such fissures that a volcano [Llaima] opened.” Likewise, he noted earthquakes felt in his homeland in 1604, while the next year “Italy exhaled and enjoyed a reprieve, hearing that this rabble [the earthquakes] had retreated to America,” where it inflicted grave damage on Peru. In such examples, Bonito is not yet thinking about the simultaneity of far-flung seismic events. He is, nonetheless, imagining the circulation of quake-inducing air currents on a novel, planetary scale. Italy and South America became hotspots studding the same system of global seismic activity even if they didn’t, in Bonito’s telling, experience earthquakes at precisely the same time. The wide assortment of earthquake reports that he had access to in Naples, transmitted across European networks of trade and conquest, inculcated his broad perspective.
Eventually, the difference of seismic degree that Bonito perceived—larger earthquakes than anything the ancients allowed for—crystallized into countenancing a difference of kind. In a sense, post-classical Europeans had long drawn quantitative and qualitative distinctions when assessing earthquakes, believing localized seismicity to typically be a natural occurrence and universal seismicity to always be divinely directed. The new question that Enlightenment natural philosophy asked was whether the ancients’ pneumatic explanation of seismicity had correctly identified the mundane mechanism, through which God may or may not act, generative of earthquakes that affected supralocal areas. Given that Aristotle only imagined small-scale seismic events, could his seismogenic theory really apply to the larger earthquakes of early modernity? By the 1750s, savants said no.
Take, for instance, the prominent exponent of the Spanish Enlightenment, Benito Jerónimo Feijoo, whose Nuevo systhema sobre la causa physica de los terremotos I referenced at the Smithsonian. Penned immediately after the infamous 1755 Lisbon earthquake, which had also sent violent shocks all throughout Spain, the volume groups five of Feijoo’s letters with several lengthy responses from his correspondents. From the first, the monk thought about Lisbon as a scalar problem, baffled by how he had felt it in Asturias at the same time as it was destroying the Portuguese capital, far to the southwest. He searched around for historical analogs and found one in the Americas, whose seismicity had so captured Bonito’s imagination a half-century prior. Through the published reports of Catholic missionaries, those allied agents of European imperialism, Feijoo knew of the 1663 Charlevoix earthquake in New France, which extended over some 400 leagues and had, in fact, caused structural damage even in distant Massachusetts Bay. Closer to home, there was the periodic seismic activity of southern Italy, known to occasionally stir surf along the Provençal coast hundreds of miles north. Classical examples impressed Feijoo less. The only one worthy of mention was the 17 CE earthquake in Asia Minor, which he conceded had inflicted significant urban ruin. Yet, he countered, the twelve cities had been clustered in an area no more than a sixth as large as Spain.
This historical review led Feijoo to conjecture ominously that earthquakes were getting worse and to name as culprit that phenomenon that so obsessed eighteenth-century philosophers: electricity. Since modern earthquakes outstripped anything that the ancients had experienced, the causal explanations that their texts offered required revision, the Spaniard reasoned. His first letter thus concluded with the observation that electricity’s “communication of movement at such enormous distances within a moment” very much resembled the “momentaneous communication” of earthquakes. Feijoo’s following letters picked up on these themes of spatiotemporal collapse.
The third letter opened with the declaration that classical authors’ vaporous theories of seismicity simply could not account for the 1755 earthquake’s effects, specifically the “circumstance of their simultaneous extension to very distant parts.” Feijoo granted that inflammation of noxious gases could cause localized seismic events, such as those experienced in the volcanic regions of Italy, Iceland, and South America. “But what man of any judgment,” he asked, “will consent to the simultaneous burning of so many mines that the entire population of Spain felt the earthquake at the same time?”. Feijoo reminded the letter’s recipient, a merchant of Cadiz, that the meticulously kept cathedral clocks of both their cities, on opposite ends of the kingdom, each read 9:45 a.m. when the earthquake ripped through. Although he was unimpressed with classical seismic history, Feijoo, unlike some of his contemporaries, did not wield electricity to completely break with classical seismic theory. The electrical matter he hypothesized accumulated beneath the surface, amplifying gaseous inflammations that would otherwise have affected much smaller areas. Feijoo thereby grafted his seismogenic hypothesis onto ancient precedent and updated Aristotle for early modernity’s intensified earthquakes. As savants like Feijoo reimagined earthquakes’ spatiotemporal parameters, seismicity became, to borrow a phrase from Lydia Barnett, “a machine for transforming local knowledge into global.” Electric earthquakes were, that is, a means to make sense of a world that invasion, migration, and commerce rendered at once larger and more entangled.
Bonito and Feijoo represent only a small sample of the many texts and manuscripts that I had the pleasure to read at Consortium member institutions over the past year and that I will incorporate into my project’s new chapter in the months to come. Helping me at every stop along the way during my fellowship were curators and librarians whose subject knowledge and commitment to their collections’ accessibility never failed to inspire. I must extend particular thanks to JoAnn Palmeri at the University of Oklahoma and Lilla Vekerdy at the Smithsonian.
