Humboldt and Bonpland's Landmark Expedition to the Spanish Colonies of South America (1799-1804)

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Humboldt and Bonpland's Landmark Expedition to the Spanish Colonies of South America (1799-1804)

Overview

Alexander von Humboldt (1769-1859), a German geologist and naturalist, and Aimé Bonpland (1773-1858), a French botanist, engaged in a new sort of scientific travel involving systematic measurement and observation of a remarkable range of organic and physical phenomena with dozens of sophisticated scientific instruments. Humboldt's ultimate goal for these researches was to understand nature as an interconnected whole. Humboldt and Bonpland inspired a generation of scientific explorers and established new methodologies and new instrumentation standards.

Background

The eighteenth-century expeditions of Charles Marie de La Condamine (1701-1774), Louis Antoine de Bougainville (1729-1811), and Captain James Cook (1728-1779) provided the model of scientific exploration followed by Humboldt and Bonpland. In all of these earlier instances scientific travelers bravely explored mysterious lands and oceans while continuously collecting specimens and measuring astronomical and geological phenomena. Upon returning home these explorers published popular and scientific accounts describing heroic adventures and exotic sights and, especially in the case of Cook, presenting a wide range of botanical, geological, oceanographical, and anthropological findings.

While mostly adhering to this model, Humboldt's efforts in particular were inspired by a range of scientific interests and a commitment to comprehensive empirical observation surpassing those of any scientific explorer before or after. Natural objects, Humboldt insisted, can be understood only within the full range of their environment: rainfall, humidity, temperature, barometric pressure, electrical charge of the air, chemical composition of the atmosphere and soil, geomagnetism, longitude, latitude, elevation, surrounding geological formations, surrounding plants and animals, and nearby human activity and culture must all be measured or observed. Humboldt called his scientific enterprise a physique du monde, or terrestrial physics. Inspired by the philosophy of Immanuel Kant (1724-1804), Humboldt was seeking to discover amid the geographical distribution and variation of phenomena nature's constant and most simple laws and forces.

Towards this end Humboldt and Bonpland carried with them an unprecedented array of instruments, all financed by Humboldt himself. Telescopes, sextants, theodolites, compasses, a magnetometer, chronometers, a pendulum, barometers, thermometers, hygrometers, a cyanometer, eudometers, a rain gauge, leyden jars, galvanic batteries, and chemical reagents were carried and used across the continent. Scientific instruments had been greatly improved in recent years both in accuracy and in portability. Humboldt had gained expertise in using these instruments through years of scientific study and travel in Europe. The expedition of Humboldt and Bonpland to the Spanish colonies, then, was truly at the frontiers of science.

For almost five years, from July 1799 to April 1804, as the Napoleonic Wars raged in Europe, Humboldt and Bonpland traveled throughout what is now Venezuela, Cuba, Colombia, Peru, Ecuador, and Mexico mapping, collecting, measuring, sketching, describing, and observing all the way. It was a tremendously arduous journey accomplished on foot, canoe, and horse with equipment carried by a caravan of as many as 20 mules or by numerous canoes assisted by Indian guides. Not surprisingly, glass jars and instruments broke. Despite the hardships Humboldt, in particular, thrived in the tropical climate, displaying tremendous energy and strength and, unlike Bonpland, rarely falling ill.

In Venezuela their primary goal was to explore the Orinoco River and discover its connection to the Amazon watershed. After trekking through Venezuelan mountains and plains they canoed the Orinico's vast system for 75 days. Humboldt performed calculations upon observations of Jupiter's moons and other celestial objects in order to map the Orinico's course. Humboldt and Bonpland also systematically collected plants while carefully measuring every possible environmental factor. Through global studies in "plant geography" Humboldt hoped to eventually be able to infer the diversity and density of vegetation at any point on Earth. Vegetation for Humboldt represented an organic force as measurable as heat or magnetism.

Upon reaching the southern border of the Spanish colonies, the explorers traveled back through Venezuela. After visiting Cuba they explored Colombia, Ecuador, and Peru for 21 months. Humboldt, an expert in geology and minerals, was particularly interested in studying volcanoes of the Andes and sites of major seismic activity for clues as to Earth's formation. Crossing the Andes four times (and setting a mountaineering record of 19,289 feet) Humboldt and Bonpland carefully measured the magnetic axes of mountains and the inclination of strata in order to understand the forces that had generated the volcanic range. By carefully attending to all the data, especially data deviating from the general north-south orientation, Humboldt hoped to develop a comprehensive dynamical theory of mountain ranges to replace what he considered simplistic explanations of his predecessors.

In January 1803 the explorers sailed to Mexico. During the voyage Humboldt charted the course of the cold coastal current that now bears his name. Humboldt and Bonpland paid special attention to Mexico's mining districts in relationship to the geology, economy, and anthropology of the country. After a year in Mexico Humboldt and Bonpland sailed to Cuba and then to Philadelphia. They met with President Thomas Jefferson, an ardent scientist himself, in Washington and Monticello. In June 1804 Humboldt and Bonpland departed Philadelphia for home carrying 30 large crates of collected materials. For all their tremendous successes they were disappointed in one thing. Originally they had planned to travel to the Philippines and other Spanish possessions throughout the globe. War and bad luck had frustrated those plans.

Impact

Upon return to Europe Humboldt and Bonpland were celebrated as heroes. Humboldt went on to write numerous books recounting the rigors of the trip and the beauty and strangeness of the mysterious continent. These books, which were widely translated and widely read, portrayed the scientist as a fearless, virile adventurer who was willing to endure any hardship for the pursuit of knowledge.

Through his voluminous popular and scientific writings on the South American expedition, Humboldt became the most famous naturalist of his day and inspired a generation of scientific explorers. He and Bonpland had proven the possibility of a sophisticated inland scientific expedition employing a vast range of the best instruments. Humboldt's quantitative, technical methodology was quickly taken up by many American explorers of the western United States and by British, German, French, and Scandinavian explorers. His model of plant geography greatly inspired, for one, Charles Darwin (1809-1882) in his studies of the geographical distribution of species. Humboldt's style of scientific travelogue, in which he vividly recounted sights, sensations, and scientific observations from a personal viewpoint, was adopted by Darwin, Alfred Russel Wallace (1823-1913), Louis Agassiz (1807-1873), and other scientific explorers. The extent of Humboldt's influence on later explorers is indicated by the number of towns, counties, rivers, and mountains bearing his name in the western United States.

Humboldt's influence extended well beyond scientific exploration. His work on plant geography became a basis of the field of plant ecology at the end of the century. His "political geography" of Mexico, which incorporated social, economic, and manifold environmental factors, was quickly emulated by other geographers. His technique of "iso-maps," which connected with lines geographical points of equal mean temperature, magnetic intensity, rainfall, and so on, was adopted by researchers in many sciences and, notably, is retained in the isobars and isotherms of our weather maps. Even painters such as the American F. E. Church responded to Humboldt's writings by journeying to the tropics to faithfully portray exotic plants amid their sublime, tangled environment.

More generally, Humboldt's scientific writings contributed to a new vision of science and nature. Under Humboldt's influence, any science centered around the isolated specimen in the laboratory had come to be branded as out-moded or even false. Nature was complex and science must attend to the myriad of interconnected factors contributing to this complexity. Humboldt was not the first to conceive of nature or science this way. Nor did all natural scientists embrace Humboldt's goal of discovering nature's unity through measurement. But through his and Bonpland's exploits in a difficult terrain with dozens of sophisticated instruments and through his extensive writings presenting data and explaining their significance, Humboldt demonstrated how such a science could be pursued.

Inspired by Humboldt's vision, many scientists turned their attention to complex phenomena such as the tides, the weather, and geomagnetism, which required heterogeneous empirical investigations across the globe. In order to study these phenomena researchers invented better, more accurate instruments and carried their instruments to diverse locations. They also adopted Humboldtian tables, graphs, and isomaps as tools for organizing and understanding data. Perhaps the most successful developments in Humboldtian science came in the field of geomagnetism. Humboldt himself had urged governments to establish global stations for observing magnetic and other phenomena. This idea gained impetus after famed German mathematician Carl Friedrich Gauss (1777-1855) successfully analyzed Humboldt's measurements in terms of spherical harmonics in 1833. Observational stations were established around the globe in the 1830s and 40s by several European nations. Especially in Britain this enterprise was motivated as much by colonial and navigational concerns as by a commitment to knowledge or international cooperation in science. In 1852 British astronomer Edward Sabine (1788-1883), comparing data tabulated at the stations in Toronto and Tasmania, determined that statistical variations in geomagnetic disturbances corresponded to the recently discovered sunspot cycle. With this discovery the science of solar-terrestrial physics was born. The success of the magnetic stations encouraged the establishment of similar observational networks, most notably in meteorology. That network is, of course, still with us today on a much larger scale.

By the middle of the nineteenth century Humboldt's mode of universal science, in which an individual single-handedly seeks to integrate understanding of a vast range of organic and physical phenomena, had become untenable. In an era of scientific specialization Humboldt was indeed the last scientific polymath. In the meantime Humboldt and Bonpland's scientific accomplishments in South America, which had so astonished their contemporaries, had been over-shadowed by the work of new generations of investigators using better instruments and pursuing geographically broader investigations.

JULIANNE TUTTLE