Humboldt's Cosmos

by Gerard Helferich

  Not only do volcanoes tend to congregate together, Humboldt was the first person to notice that they also are apt to run in more or less straight lines, as up the coast of South America. In recognition of this phenomenon, he named the majestic row of peaks extending south from Quito the “Avenue of the Volcanoes,” a term so perfectly descriptive it is still used today. The reason for this linearity, Humboldt realized, is that volcanoes are positioned along fissures in the earth’s crust, through which the lava finds an outlet to the surface.

  By the time he left the Andes, Humboldt had more direct experience of active volcanoes than anyone else who had ever lived. Thanks to his perspicacity and scientific rigor, he also understood the volcanic processes more clearly than any of his predecessors. True, there were many more questions to resolve. And Humboldt by no means was correct on every point. For instance, to his dying day he believed, along with his friend the great geologist Leopold von Buch, in the theory of “craters of elevation,” which held that mountains were formed by the subterranean upwelling of gases; if the earth’s crust were weak at a particular point, the lava forced its way through and created a volcano, but if the lava were unable to break the surface, the crust swelled like an unpopped blister. Though wrong, the idea was one of the most important geological theories of the nineteenth century, defended by Darwin and many others. Similarly, Humboldt, along with other geologists of his day (including the greatest, Charles Lyell) believed that the lava expelled from volcanoes originated deep within the earth’s core, whereas today we realize that it is formed much closer to the surface, as the result of powerful tectonic forces.

  “The philosophical study of nature endeavors, in the vicissitudes of phenomena, to connect the present with the past,” Humboldt wrote in Aspects of Nature. And there is no doubt that by the time Humboldt quit the Andes, Hutton’s principle of uniformitaritarianism—the crucial concept that the processes that shaped the earth are still at work and still visible today—offered a much more plausible connection between past and present than Werner’s idea that the world’s landforms had been sedimented out of the primordial sea in a one-time act of creation. After seeing the great mountains of the New World, Humboldt would never again consider himself a neptunist. Thus, “problems which long perplexed the geologist in his native land in these northern countries, find their solution near the equator.” And after his reports to the scientific societies of Europe and his copious publications, neptunism became an increasingly moribund theory. The old paradigm didn’t succumb all at once, but over the next two or three decades became so compromised, as it was perpetually modified to accommodate contradictory data, that it gradually ceased to resemble itself. It would be left to Sir Charles Lyell to deliver the coup de grâce, in 1830.

  That was the year that Lyell, a Scottish lawyer-turned-geologist, published the first volume of his Principles of Geology, which created an immediate sensation after its release. A landmark of scientific publishing, the three-volume work effectively reconciled vulcanism and neptunism, adopting the best parts of each and merging them into a coherent whole that formed the modern basis of the science. In fact, Lyell’s ideas went far beyond geology, and, by helping to redefine science as the study of universal, continually operating laws, influenced a host of other scientific disciplines and made a deep impact on nineteenth-century thought.

  Lyell acknowledged his obvious debt to his countryman James Hutton—and to Humboldt. In fact, Lyell visited Humboldt in Paris in 1823, when the latter was world famous and the former a twenty-six-year-old student. The older man kindly showed him around the observatory, prompting Lyell to write his father, “There are few heroes who lose so little by being approached as Humboldt.” But Lyell clearly wasn’t one to be cowed by Humboldt’s celebrity. “He was not a little interested in hearing me detail the critiques which our geologists have made on his last geologic work [Essai géognostique sur le gisement des roches dans les deux continents],” Lyell also told his father, “a work that would give him a rank in science if he had never published aught besides.”

  In the Principles, Lyell cited Humboldt no fewer than twenty-six times, on topics ranging from earthquakes to the distribution of plants and animals. He also used Humboldt’s meteorological data as well as Humboldt’s technique of isotherms to illustrate his own ideas on climate. Indeed, Lyell’s theory of climate built directly on the other’s: Whereas Humboldt had suggested that differences in climate between the northern and southern hemispheres were the result of differences in their relative sizes, Lyell generalized from this to state that all differences in climate were due to differences in physical geography and that past climatic shifts had been caused by changes in the proportion of land and sea. (Today we understand that other factors, such as the composition of the atmosphere, play important roles in climate change as well.) Lyell accepted Humboldt’s ideas on several other points, including that volcanoes tended to be positioned along distinct lines on the earth’s crust, that they were connected beneath the surface, and that volcanoes and earthquakes were different manifestations of the same underlying phenomenon.

  Not even all Lyell’s theories were vindicated, though—for example, he believed that volcanoes were somehow dependent on seawater (since so many volcanoes were found in the ocean or along the coast), and, as mentioned above, that volcanoes’ heat came from the earth’s primordial core. Still, Lyell’s work was a fundamental breakthrough in geology, representing the resolution of the science’s principal controversy and, as the book’s title implied, the first compelling articulation of the principles that would guide the discipline into a new age.

  Just as Lyell had drawn from Humboldt, others were greatly influenced by Lyell, including perhaps the greatest name in nineteenth-century science—Charles Darwin. Along with the Bible and Humboldt’s Personal Narrative, Darwin shipped on board the Beagle the Principles of Geology, which he found a revelation. As the young Briton made his round-the-world voyage, Lyell’s ideas supplied a crucial framework on which to fix his own thoughts concerning geologic and biological change on earth. For one thing, the sort of incremental modifications in species that Darwin would ultimately theorize required an immensely long period over which to operate—clearly longer than the six thousand years that had, according to contemporary interpretations of the Bible, lapsed since the Creation. However, the enormous geologic modifications that Lyell suggested required an even longer period. If the earth were ancient enough to accommodate those changes, it was clearly old enough to accommodate natural selection.

  In addition, as Lyell had adapted to geology Isaac Newton’s principle of vera causa—theidea that a cause must be independently verifiable—Darwin adapted the principle of uniformitarianism to biology: Just as the earth’s landforms had not been produced by a unique act of creation, but had been shaped by age-old processes that were still operating and still observable today, the world’s species had not resulted from a one-time act of creation, but had evolved—and were still evolving—according to universal principles. Recognizing the congruence with his own work, Lyell became an early supporter of natural selection after On the Origin of the Species was published in 1859. For his part, Darwin acknowledged, “The science of geology is enormously indebted to Lyell—more so, I believe, than to any other man who ever lived.”

  HUMBOLDT’S unplanned trek across the Andes would have momentous significance for him as well as for the disciplines he studied. Not only would his partial ascent of Chimborazo catapult him to international celebrity, Humboldt’s thinking began taking exciting new turns in the Andes, especially concerning the origin of volcanoes and the formation of mountains. In the coming years, the ideas he had germinated in this barren landscape would revolutionize geology—and, through their influence on such seminal figures as Charles Darwin and Charles Lyell, would exert a profound effect on the course of science itself.

  But Humboldt wasn’t yet through with the great mountains of South America. Lima, where he hoped to find passage to Mexico
, lay some eight hundred miles to the south.

  Ten: Cajamarca

  AT more than nineteen thousand feet, the massive, snow-covered, nearly symmetrical cone of Cotopaxi presents the picture-perfect image of a volcano. The type geologists call composite (i.e., with layers of lava alternating with those of ejected stones and ash), the peak towers over the Ecuadorean altiplano about forty miles south of Quito. But on its southern face, Cotopaxi’s symmetrical perfection is marred near the summit by a thousand-foot-tall protuberance called la Cabeza del Inca, “the Head of the Inca,” which, according to legend, was created by an explosive eruption in 1533, the year Francisco Pizarro executed the Inca Atahualpa.

  One of the tallest active volcanoes in the world, Cotopaxi has been the most destructive in all of South America. Since 1534, it has erupted ten times, including five particularly devastating outbursts in the eighteenth century, in 1742, 1743, 1744, 1766, and 1769. In the last of these, the shower of ash was said to be so dense that residents of the indomitable town of Latacunga (wiped out by the volcano on three separate occasions) were forced to use lanterns to navigate in the middle of the afternoon.

  But when Humboldt visited Cotopaxi, in September 1802, the volcano was quiet. Stopping at the nearby hacienda La Ciénega, where the “Humboldt Suite” has been preserved to this day, he sketched the mountain, which he considered “one of the most majestic and awe-inspiring views I ever beheld in either hemisphere.” Fresh from their triumph on Chimborazo, the travelers decided to make an attempt on Cotopaxi. It’s not known what route they chose, but at fourteen thousand feet, just below the snow line, they were forced back by loose, wet ash. Humboldt pronounced the peak unclimbable. And so it would remain for seventy years, till 1872, when German scientist and explorer Wilhelm Reiss and his Colombian companion Angel Escobar gained the rim of the crater by following a still-warm lava flow up the western side. Eight years later, Edward Whymper, hero of the Matterhorn and Chimborazo, climbed Cotopaxi’s north face and spent the night on the summit; today his route is the standard path to the top.

  From Cotopaxi, the explorers turned south. Humboldt intended to cross the mountains to the Pacific Coast, where he hoped to find a ship to Mexico. From there, he planned to sail to the Philippines, then continue his voyage around the world.

  At Riobamba, the town about a hundred miles south of Quito where the disastrous earthquake of 1797 had been centered, the travelers stayed for a few weeks with Carlos Montúfar’s brother, who served as the local magistrate. Here Humboldt had the opportunity to inspect some sixteenth-century manuscripts written in a pre-Inca language called Purugayan, which had been translated into Spanish. In the possession of a cultured man named Leandro Zapla, who claimed to be an Indian prince, the manuscripts related the dramatic story of a volcanic eruption and the religious and political significance that the local shamans had ascribed to it.

  To Humboldt, the manuscripts were an epiphany, captivating the romantic side of his nature with their glimpse of bygone glories. In fact, they “revived in me,” he wrote his brother, “the wish to study the early history of the aborigines of these countries . . . ,” whose “languages suffice to give evidence of a higher civilization before the Spanish conquest in 1492. . . . The priests of those ages,” for instance, “possessed sufficient knowledge of astronomy to draw a meridian line and to observe the actual moment of the solstice. They changed the lunar into the solar year by the inter-calculation of days, and I have in my possession a stone in the form of a heptagon which was found at Bogotá, and which was employed by them in the calculation of their calendar.”

  This evidence convinced Humboldt that a sophisticated civilization had once flourished in these mountains. But the Spanish, intent on their agenda of salvation and conquest, had never cared to delve into the astounding achievements of these native cultures. In Venezuela and Colombia, Humboldt had suggested that the Indian peoples he saw were the debased remnants of an earlier, more advanced nation. Now in the Andes, he at last found tangible evidence of a great indigenous civilization. In the coming months, as he trekked through Peru, the Inca’s ancient homeland, Humboldt would fix his attention on this magnificent culture with the same determination and perspicacity with which he’d examined the continent’s botanical, zoological, and geological treasures.

  Traveling south-southeast, the party passed over stormy, ten-thousand-foot-high páramos dotted with alpine vegetation and ravaged by violent hailstorms. Humboldt was still eager for his first glimpse of the Pacific, and the muleteers had assured him that from the Inca ruins on the Páramo de Guamini, between Loja and Guancabamba, he would be able to make out “the sea itself which we so much desired to behold.” But when the travelers reached the site, they were dismayed to see that thick mist covered the plain, obscuring whatever view of the Pacific there might have been. Instead of the ocean, they “saw only various shaped masses of rock alternately rise like islands above the waving sea of mist, and again disappear, as had been the case in our view from the Peak of Tenerife.”

  Leaving New Grenada, the explorers entered the fabled country of Peru, whose name is thought to derive from a Native American nation called either Virú or Birú. “After a residence of an entire year on the crest of the chain of the Andes or Antis, between 4 degrees north and 4 degrees south latitude . . . ,” Humboldt wrote, “we rejoiced in descending gradually through the milder climate of the Quina-yielding forests of Loja. . . .” Quina (the Quechua Indian word for “bark”), also known as quinine, was the product of the renowned cinchona tree.

  A genus of evergreen trees and shrubs found in high, humid areas ranging from Bolivia to Colombia and in some regions of Central America, cinchona had been used by native peoples to control malarial and other fevers for centuries. The plant’s name commemorates Francisca Henríquez de Ribera, the countess of Chinchón, wife of the Peruvian viceroy, who, according to an apocryphal story, carried some of the bark to Spain after being successfully treated with it in 1638. More likely, it was a Jesuit priest who introduced the substance to Europe; in fact, it was once known as Jesuit’s bark. But La Condamine repeated the Chinchón story to Linnaeus, who named the plant in the countess’s honor. (When Humboldt and Bonpland discovered a new species of cinchona, they returned the Frenchman’s courtesy, calling it Chinchona condaminea. “This beautiful tree is adorned with leaves five inches long and two broad . . . ,” Humboldt wrote, “and as it spreads its upper branches, the foliage glistens from a distance with a peculiar reddish tint when moved by the wind.”)

  Even after the bark was introduced to Europe, its use spread slowly among Protestant nations, who were suspicious of its Spanish, Catholic provenance. In 1820, French chemists J. B. Caventou and P. J. Pelletier isolated the active ingredient, and over the next 130 years quinine is credited with saving more than a million lives, before being replaced by synthesized forms in the 1950s.

  Continuing southward, the travelers were forced to cross the Río Guancabamba, a tributary of the Amazon, no fewer than twenty-seven times. The Guancabamba was only 120 to 150 feet wide—a creek compared to the miles-wide rivers they had encountered in the rain forest. But it was a “torrent . . . ,” Humboldt said, “so strong and rapid that in fording it, our heavily laden mules were often in danger of being swept away by the flood.” Worse, the animals “carried our manuscripts, our dried plants, and all that we had been collecting for a year past [since they had divided their collections in Cuba]. Under such circumstances, one watched from the other side of the stream with very anxious suspense until the long train of eighteen or twenty beasts of burden had passed in safety.”

  Farther downstream, Humboldt discovered that the Guancabamba’s swift current was harnessed to deliver mail all the way to the Pacific Coast, via el correo que nada, or “the mail that swims.” In this unique postal system, a young Indian man would carefully tie outgoing letters into a large cotton handkerchief, which he would wind around his head like a turban. Then he would jump into the river (crocodile-free here
owing to the strong current) and ride it downstream for two days, occasionally gripping a balsa log to rest and climbing ashore wherever necessary to avoid the many waterfalls. At night he would stop at one of the huts along the way, where he would be provided with a meal and a place to sleep. Though el correo que nada may not conform to conventional notions of postal efficiency, according to the governor of the province, the mail was rarely lost or damaged, and after returning to Paris, Humboldt himself received letters that had been posted this way. Indeed, the river was used to transport more than correspondence. Humboldt also reported seeing groups of thirty to forty Indians—men, women, and children—bobbing sociably downstream as the current swept them to their destination.

  As the travelers approached the Amazon Basin, Humboldt was “cheered by the aspect of a beautiful, and occasionally very luxuriant vegetation,” including a new species of bougainvillea with bright-red bracts, the finest orange trees he had ever seen, and a remarkable tree named Porlieria hygrometrica, which would predict a coming storm by closing its fine leaflets. (“It very rarely deceived us,” Humboldt testified.)