Once Alexander von Humboldt settled down in Paris after his monumental five-year journey through the Americas, he started to publish books. Among the first was a massive coffee-table extravaganza titled Vues des Cordillères, et monumens des peuples indigènes de l’Amérique (Views of the Cordilleras and monuments of the indigenous peoples of America). If you are ever so lucky as to find a copy, open it to the first plate, “Statue of an Azteck Priestess” (fig. 1).
Crouched like a sphinx, stony, inscrutable, she gazes blankly out over your right shoulder, lips parted as if to speak. She looks vaguely Egyptian. Does this mean that the peoples of the Nile sent emissaries to the New World? Or did the Aztecs invent, on their own, similar sculptural forms? Humboldt thinks the latter, though he does note a case of genuine long-distance transmission: the pearls that ornament the priestess’s forehead show that the cosmopolitan city of Tenochtitlan, located high in the Mexican interior plains, was in contact with the California coast, “where pearls are fished up in great numbers.” Contemplating the statue leaves Humboldt with a congeries of questions: Why has she feet but no hands? Is she truly a priestess? A deity? Or simply an Aztec woman? Where did such imagery originate? Perhaps here is a reflection of the light from Asia that led to “the commencement of American civilization.” But these questions cannot be answered. In the vacuum left by the wholesale Spanish destruction of her civilization, the words she speaks cannot be heard. She reigns, silenced, mysterious, alien yet familiar, over the entirety of Humboldt’s works.
Humboldt’s next plate points directly to the cause of her silence and mystery (fig. 2). It shows the center of what was once her city—but now it is the center of Mexico City, a trim and elaborate European square built, as Humboldt points out, on the site of Tenochtitlan, “totally destroyed” by the Spanish in 1521. Not one stone was left on another, and out of Tenochtitlan’s shattered buildings the Spanish quarried the materials for their new capital. Humboldt’s image is therefore a palimpsest: where the square stands, there formerly stood the spacious temple of Mexitli. Behind the cathedral once stood the palace of the king of Axajacatl, where Montezuma lodged his guests, the Spaniards. To the right of the cathedral now stands the palace of the viceroy of New Spain; to the left once stood Montezuma’s own palace. These specifics may, Humboldt drily remarks, interest those who study the conquest of Mexico. Here, in its opulent presence, ready to vie with the finest cities of Europe, rises an erasure of all the past, the heart of the American civilization Humboldt is attempting to resurrect. Where are its people? Humboldt admires the great equestrian statue of his patron Carlos IV in the center of the square but notes that the Indians call it “the great horse” (not “the great king”); he also notes that the four ornamental gates to the statue’s raised enclosure are kept “closed, to the great discontent of the natives.” Indeed, the square itself is strikingly vacant, the inhabitants evacuated. Humboldt peoples the margins of this apparently European city not with elegant Spaniards or bustling Creoles but with a handful of “Guachinangoes,” the mixed race “lower class of the Mexican people”: their places destroyed, they yet remain, the erased and the excluded, strolling through the space of their ancestors, gazing on the emptiness that was their history.
Next in this sequence comes the first of Humboldt’s natural scenes (fig. 3). The German scholar Ottmar Ette has remarked that in Humboldt, the ocean becomes “not the separating element but the one that engages everything into worldwide communication and connects everything.” Here, in Natural Bridges of Icononzo, is an image of separation and connection iconic of all Humboldt’s work, itself a bridge between natural and human. His text tells us that in the Andean high plains it is not the mountains but the valleys that stagger the European imagination, for they carve depth into the landscape, a wild aspect that fills the soul with “astonishment and terror.” Icononzo is the name of the ancient Muysco Indian village at the southern end of the valley of Pandi in the kingdom of New Granada (now known as Colombia), a valley sliced in two by this impassible gulf which yet is bridged, twice, by the hand of nature. Down its length thunders the Rio de la Summa Paz. Humboldt believes this chasm to have been created by an earthquake, which a single stratum of compact quartzose resisted, forming a natural bridge nearly a hundred meters above the torrent below. The second, lower bridge was formed when masses of rock tumbled into the gulf in such a way as to support each other, with the middle rock forming a keystone—a fact which in time, he speculates, might have given the Indians the concept of the arch, unknown to the Americas as it was to ancient Egypt. Here in this image are natural history and human purpose united: travelers use the upper bridge to pass between the valley’s northern and southern halves, and there on its flank the Indians have erected for the safety of travelers “a small balustrade of reeds.”
That these bridges are natural is important: they were already inscribed in nature, principles of architecture embodied in unworked stone. But humans have discovered them and use them—and so there is that frail reed fence: Don’t fall off! it cries. The artist, down in the riverbed looking up, turns utility into aesthetics, a lived experiential reality into a “view.” Yet this view can exist only in imagination. True, it is based on Humboldt’s own sketch, made in the field—but Humboldt sketched the bridges from the northern valley above, in a side view. The Paris artist has accomplished the impossible, vaulted us to the midst of the river far below, a place so dark and inaccessible that the only way Humboldt can see the thousands of cave-dwelling birds that live and fly in its depths is to bounce rockets off the canyon sides and glimpse them flying in the flare of artificial light.
In this view not just two but many worlds cross: the plate tectonics that split open the rock, the waters that plunge down the crevasse, the vegetation that clothes the rock walls, the birds who call this chasm home and fill it with their “lugubrious cries,” the Muysco Indians who name the birds—cacas, Humboldt tells us—and who travel to market across this bridge, the European scientist who ventures to place the Cordilleran birds in their Linnaean genus, Caprimulgus, even as he records the native’s speech and sketches the site in his notebook, the artist, M. Bouquet of Paris, who reimagined Humboldt’s field sketch as a sublime view, the viewer who sees in this one image the braiding together of fact and beauty, science and poetry, nature and society, history poised on the present instant.
The discipline I work within is conventionally named “literature,” understood to include that subset of written texts encompassing fiction and poetry and understood as “aesthetic”—expressive and emotive—rather than “scientific,” objective and factual, or “political,” social and contested. But Humboldt resisted the tectonic shift that was splitting the world of knowledge under his feet even as he wrote and lived, and in his writings he created his own natural bridge. More: this is not a light structure thrown across like a plank to provide perilous passage between two great realms. It is pulled into place by gravity and by its weight supports the whole, becoming the keystone to Humboldt’s cosmic architecture. Humboldt chose the title for his late work, Cosmos, with care; though it daunted him a little, he stood by it, for it allowed him to articulate both landings of his bridge: first, what Thoreau called “hard matter and rocks in place,” the physical universe as it exists apart from human purpose; and second, the beauty and order of that universe, the very idea of the whole. The physical universe exists without us, no doubt, beyond us and other than us; but the Cosmos needs us. Only in the dance of world and mind, subject and object, does Humboldt’s Cosmos come into being. It is the act of human art—as in this very image—to represent the real, not to copy or replicate it but to make it “present” to our minds and hearts and souls, an image or trace of the Cosmos realized, renewed, and revitalized in mind.
Vues des Cordillères was a gorgeous production, but it priced itself right out of the market; only a few copies exist in the United States today. So Humboldt’s friend, the English radical poet and publisher Helen Maria Williams, persuaded him to select just a few of the illustrations and republish the book in a smaller and cheaper London edition. Her translation, published in 1814 under the rather gusty title (complete with exclamation point) Researches concerning the Institutions and Monuments of the Ancient Inhabitants of America, with Descriptions and Views of Some of the Most Striking Scenes in the Cordilleras!, circulated Humboldt’s ideas much more widely among English-speaking audiences. In any language, this was a very odd book, a jumble tossing together sculpture, costumes, mountains, buildings, hieroglyphs, waterfalls, calendars, pyramids, and geological wonders. Was there a method to this joyous, exuberant madness? Yes: each illustration is supported by an essay, and each essay references an illustration. As text and picture, theory and illustration, complete each other, so do science and art, nature and mind. The landscape cannot be understood without its people, nor can the various cultures and civilizations Humboldt documents be understood without seeing the landscape that shaped them and that they, in turn, shaped. Thus the experimental, hybrid form of this book puts on display the complex ways in which nature and culture produce each other within the historical context of Spanish colonialism. Humboldt provided a fascinating glimpse into the exotic and secret kingdom of Spain’s New World colonies, and his illustrations not only influenced the development of Latin American art, but modeled for North American scientist-explorers a new way to represent the landscapes of the American West.
Humboldt periodically flashes into anger at the stupidity, barbarism, and fanaticism of the Spanish conquerors who destroyed all they touched, leveling the cities, burning the libraries, and abandoning what little was left to decay and misfortune. From the shards and fragments he attempts to piece together the moral, aesthetic, political, cultural, and religious life of pre-Columbian Native Americans, centering on Mexico and the Andes and borrowing from the languages and historical traditions of their descendants. His approach is deliberately comparative. How much, he asks, do New World nations resemble those of the Old World? From whence came these peoples, with their hundreds of languages, their legends and sophisticated calendars, their technologies and distinctive religions? Most likely from East Asia, he decides, pointing for evidence to linguistic, cultural, and technological roots across the Pacific among the Tibetans and the Japanese. Yet so long ago had they migrated that American nations developed wholly new and independent civilizations, in isolation from the rest of the world. The implications were startling: civilization did not dawn once in the Old World, spreading outward from a single cradle; it had multiple centers of origin, many cradles, and one of them was in the New World. Given the affinity of the hundreds of American languages and the similarities in “the cosmogonies, the monuments, the hieroglyphics, and institutions,” Humboldt is convinced that a single people entered North America from Asia to spread and diversify across two continents.
Many cradles, but one people. Everywhere Humboldt looks he sees one great truth verified: “The Caucasian, Mongul, American, Malay, and Negro races” are not “insulated” from one another but form one “great family of the human race, one single organic type, modified by circumstances which perhaps will ever remain unknown.” If all humanity forms one “great family,” then all human works, even those that do not meet our European standards of beauty, are worthy of respect and attention, for they all tell a part of the greater human story. As Humboldt says, different nations have followed many “different roads in their progress toward social perfection,” and their progress is helped or hindered not by internal, biological limitations of race but by external, or environmental, circumstances and accidents. The Americas, for instance, lacked milk-giving ruminants capable of domestication. Instead of cattle, the Asian immigrants encountered untamable musk oxen and bison, and so their road from hunting to agriculture necessarily skipped over the supposedly required “pastoral” stage, derailing the traditional doctrine that human cultures must advance through the three “stages” of hunting, herding, and agriculture. By another trick of geography, American peoples were cut off from communication with the rest of mankind, left to struggle with a “savage and disordered nature” with no resources other than their own ingenuity. Who can wonder, then, at the apparently “rude” style or “incorrect” expression of the arts of native America, or at their slower progress? How many nations, asks Humboldt, can boast the mild climate of the gentle Mediterranean?
Humboldt argues, then, that all races form one great human family, and their great diversity comes from adapting to their many and various environments. Since environment is crucial to understanding how human unity flowers into such diverse societies, the only way to understand a people is to become immersed in their landscape. Cultures cannot be judged from afar. Scholars who “never quitted Europe” say foolish things—for instance, that America is a marshy country with few animals, overrun by savage hordes. Travel allows us to overcome such prejudices, to explore the ways human and natural history shed mutual light on each other, and so Humboldt’s method emerges in his book’s mad scramble of nature and culture. As he declares, “An accurate knowledge of the origin of the arts can be acquired only from studying the nature of the site where they arose.” Archaeological research must take into account climate and soil, the presence or absence of animals, the physiognomy of plants and of landforms, for they all influence the progress and style of human arts. Thus his landscape views are not intended as decorative but to drive forward his argument: the cultures of the mountain peoples of the Cordilleras are stamped by the massive and wild nature of their high peaks and hanging valleys. After apologizing for the book’s lack of order, Humboldt ends his introduction with a frustrated but hopeful note: may his “feeble sketches” lead other travelers to visit these regions and “retrace accurately” the “stupendous scenes, to which the Old Continent offers no resemblance.”
Travelers came, of course, not all of them so idealistic as Humboldt. In his time, the face of nature he so loved was being remade by colonial imperialism, global capitalism, and the industrial revolution. He himself was a knowing participant, both in creating and circulating new regimes of knowledge and in helping to construct a global economy that would, he perhaps naively believed, advance the cause of freedom through free trade and the open exchange of ideas. Though his ideas and methods were co-opted by the imperialist projects of Europe and the United States, Humboldt consistently protested against the evils of colonial exploitation, particularly slavery and the oppression of indigenous peoples, and he deliberately incorporated the voices and knowledges of ethnic and colonial peoples into his planetary project.
Humboldt attempted, in short, to create a counternarrative to the drumbeat of imperial progress, and in this attempt he effectively created what we would now call an environmental discourse. His foundational assumption was that neither humans nor nature can be understood in isolation. In his social writings, nature was never merely background but played an essential role in the development of human societies; in his natural writings, the ways various societies construct their views of nature were crucial to understanding their physical environment. For Humboldt that environment was overwhelmingly historical and spatial: though he worked some in physics and chemistry, his interests always centered on the Earth and the processes that generate its forms and surfaces. His scientific methods were relentlessly inductive, for he sought to identify patterns in nature by combining and collating hundreds of measurements—myriads of data points—until out of what the Russian physical geographer Peter Kropotkin called “the bewildering chaos of scattered observations” flashed a new vision of the “harmonious whole” they described, “like an Alpine chain suddenly emerging in all its grandeur from the mists which concealed it the moment before, glittering under the rays of the sun in all its simplicity and variety, all its mightiness and beauty.” Far out on the horizon, “the eye detects the outlines of new and still wider generalizations.” As Kropotkin’s lyrical description suggests, such quantitative work was not the enemy but the ally to poetic insight. For the Humboldtian scientist, the doing of science combined rigorous and exacting labor with the joy of poetic creation and an almost spiritual sense of revelation, as if nature borrowed the mind and hand of the scientist to describe its own most beautiful laws and structures.
Generating an environmental discourse was only half the journey. To complete it meant enrolling others to the cause: in letters and mentoring relationships with young scientists and artists, salon conversations, political negotiations, the organization of scientific societies and international scientific research, and lectures and publications both popular and technical, Humboldt sought to create institutions and practices that would spread his particular way of thinking about humans and nature. In one sense he succeeded spectacularly. He virtually invented modern international science and seeded so many fields with productive new ideas that historians of science call the era “Humboldtian.” However, the scientific results of his initiating efforts eventually passed him by, and by his death his predisciplinary insistence that the physical and natural sciences, economics, politics, cultural history, ethnology, linguistics, and aesthetics all be practiced together in an environmental network of interacting discourses was resisted as heroic but impossible, fractured by the rise of specialization and standards of scientific objectivity, and suppressed as useless and old-fashioned. The old Baron, the most loquacious man of his time, was effectively silenced.
This silencing has done real damage to environmental studies, for Humboldt stands at the head of environmental and ecological thinking today. Recovering Humboldt does more than deepen our knowledge of the long foreground of such iconic figures as Henry David Thoreau, George Perkins Marsh, and John Muir—Humboldtians all. First, it locates the first global wave of environmental studies just prior to the era of scientific specialization, when scientific discourses were fluid and a single mind could still innovate in multiple disciplines across the humanities and social and natural sciences, allowing each to inform the others. Second, and more importantly, it places at the head of environmental studies an alternative narrative that closes the gap between mind and nature by demonstrating how each creates or constructs the other—a concept that, thanks to modernism’s persistent dualisms, still seems novel today.
Finally, recovering Humboldt positions the first wave of environmental thinking not within a nationalistic debate over resource exploitation but within a global debate over capitalism and imperial power. The apparent roots of Anglo-American nature writing in imperial discourses of exploration have made it too easy to dismiss such writing as ideologically complicit. But the story is deeper and more complex than this. Humboldt grew up knowing that nature was the site of deeply political conflict, and his popular works deplored the tragic destruction of the civilizations of the Americas and tried to reconnect them with the global human community, by showing that colonial exploitation of the land went hand in hand with the destruction and continuing oppression of its ethnic peoples. Building on the insights of eighteenth-century colonial scientists, Humboldt became what Ramachandra Guha calls “a pioneering analyst of global deforestation,” arguing as early as 1805 that cutting down forests causes climate change, and in later works attributing the alarming and inexplicable fall in water levels in both Mexico’s Lake Tetzcoco and Venezuela’s Lake Valencia to deforestation by the Spanish, which desiccated the landscape and caused periodic destructive floods. This cycle was made even worse in Mexico by imperial Spain’s ill-informed and catastrophic attempt to reengineer Mexico City’s water system, in which colonial rulers forced natives to build a massive canal to drain the upland lakes. As Humboldt documents, the folly of the Europeans ruined once-plentiful water resources and poisoned once-fertile agricultural land, and their abusive labor practices killed untold numbers of workers and plunged the entire Indian population into poverty.
Richard Grove argues that the nineteenth-century growth of natural knowledge and resulting new ecological concepts of nature were—and are—inseparable from European colonialism. Humboldt added the necessary conclusion that environmental destruction was also socially devastating: natural ecology entails social ecology. In Humboldt the two were forged together, humans and nature forming two sides of the same coin. Humboldt’s work is refracted in the writings of Henry David Thoreau, who also joined the causes of natural and social justice; their separation into non-communicating fields came later. As Aaron Sachs has recently argued, today, with social justice forming an exciting new front in ecocriticism, recovering Humboldt would open a radical environmental tradition that would link with the social justice orientation of postcolonialism. Splitting humans from nature has other consequences, too: the separation of scientific from literary knowledge is now so total that leading ecocritics like Ursula Heise can see no viable connection. Academic environmental studies have “to date not established any significant links between literary and scientific approaches to the environment.” Instead, literature and art have become “bulwarks” against the encroachments of science and technology rather than “sites of encounter between different types of knowledge and discourse.” Even works sympathetic to science show no “conceptual bridging between scientific description and aesthetic valuation.”
We are back, standing, once again, on Humboldt’s bridge. Two hundred years later, does it still hold? Or has it, too, broken into ruins, one more monument to a lost civilization? Let us imagine it holding. In bridging peoples, disciplines, places, and historical eras, Humboldt sought to create a zone of exchange rather than domination, a pluriform and multivocalic world that would allow humans and natures to speak through a range of representations, from scientific to social to aesthetic, augmenting the stripped-down world of scientific fact by presenting those facts as elements of a renewed and revitalized Cosmos. Humboldt tried to intervene at the discursive level—which is to say he collected, he wrote, published, and lectured, voluminously and persistently, letter by letter, essay by essay, book by book, person by person, building over seventy years a massive global network of scientific and cultural knowledge and artistic expression by which he hoped to bring natural knowledge into the public sphere as a form of liberation. In an era of bloodshed, revolution, imperial warfare, and Malthusian struggle against a nature “red in tooth and claw,” Humboldt found in nature not limitation and conflict but freedom, justice, and harmony. His was a quixotic vision, aimed at changing the course of history, and it failed.
But not entirely. Humboldt’s subversive vision of science for the people lived on in Europe (most provocatively in the work of Peter Kropotkin), and in the United States he succeeded in bringing into being a discourse, a way of speaking, about nature that we now call “environmental”: namely, a planetary interactive causal network operating across multiple scale levels, temporal and spatial, individual to social to natural, scientific to aesthetic to spiritual. Darwin, one of Humboldt’s closest readers, would envision an interactive network of chance and inheritance working across time and space to evolve new life forms. Thoreau, another of Humboldt’s closest readers, would recast Humboldt’s methods into the idiom of American Transcendentalism, thereby, with John Muir, the “American Humboldt,” and George Perkins Marsh, another Humboldt convert, founding North American environmental thought. Soon this new discourse of nature would receive a name: ecology. The new name designated a science, one more subspecialty in the widening panorama of natural knowledges. But before it was a science, before it could be a science, “ecology” was a discourse. It was, in fact, Humboldt’s discourse. It had first to be imagined, thence to be represented, circulated, and reimagined in works of great beauty and power, from Humboldt forward, among thinkers, poets, and painters. His writings and ideas are like a rhizome, the root connecting a ramifying community: Coleridge, Darwin, Emerson, Susan Cooper, Thoreau, Whitman, and Poe; George Catlin and Frederic Church; John Muir and George Perkins Marsh; Franz Boas and Lewis Mumford. Each was moved by Humboldt’s words and pictures to imagine a new way of envisioning nature, a way that stamped its mark on a distinctive American literature and art and that remains alive in American culture today.
Acknowledgements: Reprinted with permission from The Passage to Cosmos: Alexander von Humboldt and the Shaping of America by Laura Dassow Walls, published by The University of Chicago Press. © 2009 by The University of Chicago. All rights reserved.
Figure 1. Statue of an Azteck Priestess, plate 1, Alexander von Humboldt, Vues des Cordillères (Paris, 1810). Rare Books and Special Collections, University of South Carolina Libraries.
Figure 2. View of the Great Square of Mexico, plate 3, Alexander von Humboldt, Vues des Cordillères (Paris, 1810). Rare Books and Special Collections, University of South Carolina Libraries.
Figure 3. Natural Bridges of Icononzo. Plate 4, Alexander Von Humboldt, Vues des Cordilleres (Paris 1810). Rare Books and Special Collections, University of South Carolina Libraries.
 A. von Humboldt, Researches Concerning the Institutions and Monuments of the Ancient Inhabitants of America, trans. H.M. Williams, 2 vols. (London, 1814; facs. ed., Amsterdam: Plenum Publishing, 1972), 1:45, 48; hereafter cited as Researches. This figure, now a major work in the canon of Aztec art, has been identified as Chalchiuhtlicue, “the goddess of groundwater.” In late May to early June the Aztecs performed a rite to her at a shrine in the middle of Lake Tetzcoco, part of the most important festival for Tlaloc, the deity of rain, meant to summon the rainy season. See plate 17 and p. 261 in The Aztec Empire, ed. Felipe Solis (New York: Guggenheim, 2004).
 Researches 1:52. The American who took Humboldt’s invitation the farthest in this direction was William Hickling Prescott, who built on the work of Humboldt, among others, to recreate the civilizations of Mexico and Peru in his two classic histories, The Conquest of Mexico and The Conquest of Peru.
 O. Ette, Literature on the Move, trans. K. Vester (Amsterdam: Rodopi, 2003), 115.
 A. Perez-Mejia, A Geography of Hard Times: Narratives about Travel to South America, 1780–1849, trans. D. Cluster (Albany: State University of New York Press, 2004), 42.
 Researches 1:22-23. D.A. Brading suggests that Humboldt believed nature rendered the Indian peoples so savage that civilization had to be introduced by “missionaries” from Asia, but this interpretation leaves Humboldt’s actual question unanswered: not where did this civilization come from, but where did the American peoples come from? See D.A. Brading, The First America: The Spanish Monarchy, Creole Patriots, and the Liberal State, 1492–1867 (Cambridge, UK: Cambridge University Press, 1991), 524-25.
 Researches 1:14–15, 6, 31, 27. For Humboldt’s role in unseating the “three stages” argument, see F.L. Kramer, “Eduard Hahn and the End of the ‘Three Stages of Man,’” Geographical Review 57, no. 1 (January 1967): 73-89.
 Researches 1:4, 40–41, 42.
 P. Kropotkin, Memoirs of a Revolutionist (Montreal, QC, Canada: Black Rose Books, 1989), 211-12.
 R. Guha, Environmentalism: A Global History (New York: Longman, 2000), 26. Richard Grove has demonstrated Humboldt’s attention to theories explaining environmental destruction on island colonies such as Mauritius and the Eastern Caribbean, and his central role in applying these theories on a continental scale. See R. Grove, Green Imperialism: Colonial Expansion, Tropical Island Edens and the Origins of Environmentalism, 1600–1860 (Cambridge, UK: Cambridge University Press, 1995). Humboldt offers a favorable view of deforestation in Essay on the Geography of Plants, in Foundations of Biogeography: Classic Papers with Commentaries, ed. M.V. Lomolino, D.F. Sax, and J.H. Brown (Chicago, IL: University of Chicago Press, 2004), 52; his key (and much more critical) discussions of deforestation are in the generally overlooked Political Essay on the Kingdom of New Spain, trans. J. Black (London, 1811; facsimile ed., New York: AMS Press, 1966), 2:24-27, 109-130; and more widely cited Personal Narrative, trans. H.M. Williams (London: Longman, Hurst, Rees, Orme, and Brown, 1814–29), 4:63-64, 134-54.
 A. Sachs, “The Ultimate ‘Other’: Post-Colonialism and Alexander von Humboldt’s Ecological Relationship with Nature,” History and Theory, theme issue 42 (December 2003): 111-35.
 U.K. Heise, “Science and Ecocriticism,” American Book Review 18.5 (July-August 1997), 4+; posted at https://www.asle.org/wp-content/uploads/ASLE_Primer_Heise.pdf ; accessed 24 January 2020.
 The word “ecology” was coined in 1866 by the so-called German Darwin Ernst Haeckel, whose thinking was profoundly influenced by Humboldt and his followers. See D. Worster, Nature’s Economy: A History of Ecological Ideas (Cambridge, UK: Cambridge University Press, 1977), 191-93. Worster calls Humboldt “a pioneer in biological ecology” (135). For specific links between Humboldt and modern ecology, see M. Nicolson, “Humboldtian Plant Geography after Humboldt: The Link to Ecology,” British Journal of the History of Science 29 (1996): 289-310.