The Invention of Nature (8 page)

4

South America

WHEREVER HUMBOLDT AND Bonpland turned during those first weeks in Cumaná, something new caught their attention. The landscape held a spell over him, Humboldt said. The palm trees were ornamented with magnificent red blossoms, the birds and fish seemed to compete in their kaleidoscopic hues, and even the crayfish were sky blue and yellow. Pink flamingos stood one-legged at the shore and the palms’ fanned leaves mottled the white sand into a patchwork of shade and sun. There were butterflies, monkeys and so many plants to catalogue that, as Humboldt wrote to Wilhelm, ‘we run around like fools.’ Even the usually unruffled Bonpland said that he would go ‘mad if the wonders don’t stop soon’.

Having always prided himself on his systematic approach, Humboldt found it difficult to come up with a rational method of studying his surroundings. Their trunks filled so quickly that they had to order more reams of paper on which to press their plants, and sometimes they found so many specimens that they could hardly carry them back to their house. Unlike other naturalists, Humboldt was not interested in filling taxonomic gaps – he was collecting ideas rather than just natural history objects, he said. It was the ‘impression of the whole’, Humboldt wrote, that captivated his mind more than anything.

Humboldt compared everything he saw with what he had previously observed and learned in Europe. Whenever he picked up a plant, a rock or an insect, his mind raced back to what he had seen at home. The trees that grew in the plains around Cumaná, with their branches forming parasol-like canopies, reminded him of Italian pines. When seen from a distance, the sea of cacti created the same effect as the grasses in the marshes in the northern climates. Here was a valley that made him think of Derbyshire in England, or caverns similar to those in Franconia in Germany, and those in the Carpathian Mountains in eastern Europe. Everything seemed somehow connected – an idea that would come to shape his thinking about the natural world for the rest of his life.

Humboldt in South America (Illustration Credit 4.1)

Humboldt had never been happier and healthier. The heat suited him and the fevers and nervous afflictions from which he had suffered in Europe disappeared. He even put on some weight. During the day he and Bonpland collected, in the evening they sat together and wrote up their notes and at night they took astronomical observations. One such night they stood awed for hours as a meteor shower drew thousands of white tails across the sky. Humboldt’s letters home burst with excitement and brought this wondrous world into the elegant salons of Paris, Berlin and Rome. He wrote of huge spiders that ate hummingbirds and of thirty-foot snakes. Meanwhile he amazed the people of Cumaná with his instruments; his telescopes brought the moon close to them and his microscopes transformed the lice in their hair into monstrous beasts.

There was one aspect that dampened Humboldt’s joy: the slave market opposite their rented house, in Cumaná’s main square. Since the early sixteenth century the Spanish had imported slaves to their colonies in South America and continued to do so. Every morning young African men and women were put on sale. They were forced to rub themselves with coconut oil to make their skin shiny black. They were then paraded for prospective buyers, who jerked open the slaves’ mouths to examine their teeth like ‘horses in a market’. The sight made Humboldt a lifelong abolitionist.

Then, on 4 November 1799, less than four months after their arrival in South America, Humboldt for the first time felt the danger that might threaten his life and his plans. It was a hot and humid day. At midday dark clouds rolled in and by 4 p.m. thunderclaps reverberated across the town. Suddenly the ground began to tremble, almost knocking Bonpland to the floor as he was leaning over a table to examine some plants, and violently rocking Humboldt in his hammock. People ran screaming through the streets as houses crumbled, but Humboldt remained calm and climbed out of his hammock to set up his instruments. Even with the earth shaking nothing would prevent him from conducting his observations. He timed the shocks, noted how the quake rippled from north to south and took electric measurements. Yet for all his outward composure, Humboldt experienced inner turmoil. As the ground moved beneath him, it destroyed the illusion of a whole life, he wrote. Water was the element of motion, not the earth. It was like being woken, suddenly and painfully, from a dream. Until that moment he had felt an unwavering faith in the stability of nature, but he had been deceived. Now ‘we mistrust for the first time a soil, on which we had so long placed our feet with confidence,’ he said, but he was still determined to continue his travels.

He had waited for years to see the world and knew that he was putting his life in danger, but he wanted to see more. Two weeks later and after an anxious wait to draw money with his Spanish credit note (when it failed, the governor gave Humboldt money from his private funds), they left Cumaná for Caracas. In mid-November Humboldt and Bonpland – together with an Indian servant called José de la Cruz – chartered a small open thirty-foot local trading boat to sail westwards. They packed their many instruments and trunks, which were already filled with more than 4,000 plant specimens as well as insects, notebooks and tables of measurements.

Situated 3,000 feet above sea level, Caracas was home to 40,000 people. Founded by the Spanish in 1567, it was now the capital of the Captaincy General of Venezuela. Ninety-five per cent of the city’s white population were criollos, or as Humboldt called them ‘Hispano-Americans’ – white colonists of Spanish descent but born in South America. Though a majority, these South American creoles had been excluded from the highest administrative and military positions for decades. The Spanish crown had sent Spaniards to control the colonies, many of whom were less educated than the creoles. The wealthy creole plantation owners found it infuriating to be ruled by merchants dispatched from a distant mother country. The Spanish authorities treated them, some creoles complained, ‘as if they were vile slaves’.

Caracas lay nestled in a high valley skirted by mountains, near the coast. Once again Humboldt rented a house as a base from which to launch shorter excursions. From here Humboldt and Bonpland set out to scale the double-domed Silla, a mountain so close that they could see it from their house but which, to Humboldt’s surprise, no one he met in Caracas had ever climbed. On another day they rode into the foothills where they found a spring of the clearest water tumbling down a wall of shimmering rock. Observing a group of girls there, fetching water, Humboldt was suddenly struck by a memory of home. That evening he wrote in his journal: ‘Memories of Werther, Göthe and the king’s daughters’ – a reference to The Sorrows of Young Werther, in which Goethe had described a similar scene. On other occasions it was the particular shape of a tree, or a mountain, that gave him an immediate sense of familiarity. One glimpse of the stars in the southern sky or of the shape of the cacti against the horizon, was proof of how far away he was from his homeland. But then, all it took was the sudden tinkle of a cow bell or the roaring of a bull, and he was back in the meadows of Tegel.

Humboldt – far right, between the trees – sketching Silla (Illustration Credit 4.2)

‘Nature every where speaks to man in a voice,’ Humboldt said, that is ‘familiar to his soul’. These sounds were like voices from beyond the ocean that transported him in an instant from one hemisphere to another. Like the tentative pencil lines in a sketch, his new understanding of nature based on scientific observations and feelings was beginning to emerge. Memories and emotional responses, Humboldt realized, would always form part of man’s experience and understanding of nature. Imagination was like ‘a balm of miraculous healing properties’, he said.

Soon it was time to move on – inspired by the stories Humboldt had heard about the mysterious Casiquiare River. More than half a century earlier a Jesuit priest had reported that the Casiquiare connected the two great river systems of South America: the Orinoco and the Amazon. The Orinoco forms a sweeping arc from its source in the south near today’s border between Venezuela and Brazil to its delta on the north-eastern coast of Venezuela where it discharges into the Atlantic Ocean. Almost 1,000 miles further south along the coast is the mouth of the mighty Amazon – the river that crosses almost the entire continent from its source in the west in the Peruvian Andes less than 100 miles from the Pacific coast to the Brazilian Atlantic coast in the east.

Deep in the rainforest, 1,000 miles to the south of Caracas, the Casiquiare reputedly linked the network of tributaries of these two great rivers. No one had been able to prove its existence and few believed that major rivers such as the Orinoco and the Amazon could in fact be connected. All the scientific understanding of the day suggested that the Orinoco and Amazon basins had to be separated by a watershed because the idea of a natural waterway linking two large rivers was against all empirical evidence. Geographers had not found a single instance where it occurred elsewhere on the globe. In fact, the most recent map of the region showed a mountain range – the suspected watershed – exactly in the location where Humboldt had heard rumours that the Casiquiare might be.

There was much to prepare. They had to choose instruments that were small enough to fit into the narrow canoes in which they would be travelling. They needed to organize money and goods to pay for guides and food even in the deepest jungle. Before they set off, though, Humboldt dispatched letters to Europe and North America, asking his correspondents to publish them in newspapers. He understood the importance of publicity. From La Coruña in Spain, for example, Humboldt had written forty-three letters just before their departure. If he died during the voyage, he would at least not be forgotten.

On 7 February 1800, Humboldt, Bonpland and José, their servant from Cumaná, departed from Caracas on four mules, leaving behind most of their luggage and collections. To reach the Orinoco, they would have to head south on an almost exactly straight line through the huge emptiness of the Llanos – vast plains the size of France. The plan was to go to the Rio Apure, a tributary of the Orinoco about 200 miles to the south of Caracas. There they would procure a boat and provisions for their expedition at San Fernando de Apure, a Capuchin mission. First, though, they would go west, on a 100-mile detour to see the lush valleys of Aragua, one of the wealthiest agricultural regions in the colonies.

With the rainy season over, it was hot and much of the land through which they rode was arid. They crossed mountains and valleys, and after seven exhausting days, they finally saw the ‘smiling valleys of Aragua’. Stretching west were endless neat rows of corn, sugarcane and indigo. In between they could see small groves of trees, little villages, farmhouses and gardens. The farms were connected by paths lined with flowering shrubs and the houses shaded by large trees – tall ceibas clothed in thick yellow blossoms with their branches plaited into the flamboyant orange blooms of coral trees.

In the midst of the valley and surrounded by mountains was Lake Valencia. About a dozen rocky islands dotted the lake, some large enough to pasture goats and to farm. At sunset thousands of herons, flamingos and wild ducks brought the sky alive as they flew across the lake to roost on the islands. It looked idyllic but, as the locals told Humboldt, the lake’s water levels were falling rapidly. Vast swathes of land that only two decades earlier had been under water were now densely cultivated fields. What had once been islands were now hillocks on dry land as the shoreline continued to recede. Lake Valencia also had a unique ecosystem: with no outflow to the ocean and only small brooks running in, its water levels were regulated by evaporation alone. The locals believed that an underground outlet drained the lake, but Humboldt had other ideas.

Lake Valencia in the Aragua Valley (Illustration Credit 4.3)

He measured, examined and questioned. When he found fine sands on the higher levels of the islands, he realized that they had once been submerged. He also compared the annual average evaporation of rivers and lakes across the world, from southern France to the West Indies. As he investigated, he concluded that the clearing of the surrounding forests, as well as the diversion of water for irrigation, had caused the falling water levels. As agriculture had flourished in the valley, planters had drained and diverted some of the brooks that fed into the lake to irrigate their fields. They had felled trees to clear land, and with it the forest’s undergrowth – moss, brushwood and root systems – had disappeared, leaving the soils beneath exposed to the elements and incapable of water retention. Just outside Cumaná, locals had already told him that the dryness of the land had increased in tandem with the clearing of ancient groves. And on the way from Caracas to the Aragua Valley, Humboldt had noted the dry soils and bemoaned that the first colonists had ‘imprudently destroyed the forest’. As the soils had become depleted and fields had yielded less, the planters had moved west along a path of destruction. ‘Forest very decimated,’ Humboldt scribbled in his diary.

Just a few decades previously, the mountains and foothills that surrounded the Aragua Valley and Lake Valencia had been forested. Now, with the trees felled, heavy rains had washed away the soil. All this was ‘closely connected’, Humboldt concluded, because in the past the forests had shielded the soil from the sun and thereby diminished the evaporation of the moisture.

It was here, at Lake Valencia, that Humboldt developed his idea of human-induced climate change. When he published his observations, he left no doubt what he thought:

When forests are destroyed, as they are everywhere in America by the European planters, with an imprudent precipitation, the springs are entirely dried up, or become less abundant. The beds of the rivers, remaining dry during a part of the year, are converted into torrents, whenever great rains fall on the heights. The sward and moss disappearing with the brushwood from the sides of the mountains, the waters falling in rain are no longer impeded in their course: and instead of slowly augmenting the level of the rivers by progressive filtrations, they furrow during heavy showers the sides of the hills, bear down the loosened soil, and form those sudden inundations, that devastate the country.