by Val Ross
They applied to join a French expedition. But it was 1798, and the Revolutionary French government, which had so recently guillotined Frances top scientists, canceled the expedition in order to prepare for war with England. The two explorers were told that they could not leave Europe because the English were blockading the French coast.
Bonpland and Humboldt refused to be blockaded. They thought they might be able to sail from Spain, so they walked to Madrid — with Humboldt taking altitude measurements the whole way for practice. The King of Spain, intrigued by the intrepid pair, gave them special passports affixed with the royal seal. Finally, in June 1799, they boarded a Spanish mail ship bound for Venezuela and sneaked past the British.
Once there, Humboldt and Bonpland decided to head up the Orinoco River. Two hundred years before, the British privateer Sir Walter Raleigh had drawn charts suggesting that the Orinoco joined the mighty Amazon. Humboldt and Bonpland decided to confirm this. The fact that the few explorers who ever came back from these jungles told harrowing stories of fevers, hunger, the worlds deadliest snakes, and natives who shot poisoned arrows from behind the trees didn’t stop them.
Today’s map of Humboldt’s South America.
Off they went, with Native guides and a guard dog, into 2,775 km (1,725 miles) of agony. Clouds of mosguitoes stung their faces and got into their nostrils. Alligators attacked — ever curious, Humboldt paused to dissect one. They met man-eating fish and leaf-cutting ants that could chomp a road through the forest. Everyone, including the guides, got sick — except the hardy Humboldt, who happily went on collecting rock and plant specimens.
One day the explorers saw a huge horse wade into the river, buckle at the knees, faint, and drown. The guides pointed and cried, “Trembladores!”
Humboldt paid the guides to catch the creatures that killed the horse: electric eels 2 meters (6 feet) long. Moving closer, Humboldt accidentally stepped on one. A massive current shot him a violent jolt of pure pain. As soon as he could grip a pen again, the intrepid scientist wrote, “I do not remember a more dreadful shock!”
MEASURING ALTITUDE
How do you measure the height of a mountain? Surveyors used barometers to measure changes in atmospheric pressure — the higher you go, the less air pressure there is. The trouble was, early barometers were bulky and fragile. They also used thermometers — the higher up you go, the lower the temperature at which water boils, so you can calculate altitude by taking the temperature of boiling water. The trouble with both methods was that you had to go up the mountain to get a reading of its height.
It was easier to use triangulation of vertical angles. And for that, surveyors used a theodolite, a telescope mounted on special bases so that it could pivot horizontally around a ring marking the angles of the flat plane, and vertically around another ring marking the angle of elevation. With a theodolite, you could take sightings of the mountain’s peak from two different positions on the ground and then do your calculations. In 1850, Radhanath Sickdhar, a mathematical genius who worked with the Great Indian Survey, used triangulation to determine that Mount Everest in the Himalayas was in fact the world’s highest mountain. Its height of 8,848 meters (29,028 feet) was confirmed by a later Indian survey in 1952.
As Humboldt and Bonpland pressed on, their food ran out and they had to live on wild bananas. Jaguars killed the expedition dog. Yet despite the heat and hideous conditions, they took such accurate readings that Humboldt was later able to produce the first reliable maps of the region. They proved that that a small river, the Casiquiare, links the Orinoco to the Amazon River system.
Mount Chimborazo, an Ecuadorian volcano, was depicted by Humboldt as a cross section, so he could relate the different types of plants he noted to the height at which they grew.
When they finally emerged from the jungle, Humboldt and Bonpland shipped thousands of specimens back to Europe and set off again — west to Ecuador and the Andes Mountains. Here, it was believed, was the world’s tallest mountain, Chimborazo. The climb was an ordeal, but they survived it, and Humboldt started setting down the information he had gathered there.
For Humboldt, it was not enough to use maps to show position and place. He was one of the first mapmakers to develop thematic maps, maps that present information in terms of position and patterns: distribution of plants, location of ancient cities, agriculture, water temperature, or storms.
Leaving the Andes, the two scientists mounted their mules and headed for Lima, capital of Peru. There, they hoped to observe the transit of the planet Mercury across the sun and to see the world’s greatest ocean.
As they clopped along, they expected to see a vast blue Pacific. Instead, what they saw was gray water under low clouds. Across the sea blew a steady southerly wind, damp and cool in their faces. It always seemed as if it was about to rain, yet local people told them that sometimes it didn’t rain for years. In fact, the landscape through which they rode was one of the worlds driest deserts. Riding into the ruins of the ancient city of Chanchan, capital of the long-vanished Chimu people, the men were puzzled to see that it had once been a town of reservoirs and gardens. Now the reservoirs were empty, the gardens bone dry.
While Bonpland complained that there were no plants for him to study, Humboldt waded out into the Pacific. Taking the water’s temperature, he had a surprise. While the air was hot, the seawater was cool. And there seemed to be a current pushing this cool water northward. Could it be coming all the way from the icy Antarctic?
Modern weather maps like this one are based on the work pioneered by Alexander von Humboldt, who drew lines connecting all the points with a common temperature (isotherms). Once people could see where warm and cool air masses were, they could predict where they would move to.
As the two men rode towards Lima they encountered a smell that nearly gagged them. Fishermen told them the stench was coming from an island offshore covered in bird droppings. And indeed, the sky over the Pacific was alive with sea birds, wheeling and diving above the waves. Bird droppings, or guano, make splendid fertilizer. Suddenly the two naturalists understood how those ancient cities had sustained themselves in this desert — with guano fertilizer and water brought down from the misty Andes.
But why were there so many birds? Watching them swoop up from the sea with fish flapping in their beaks, Humboldt realized that the strong, cool current supported one of the worlds richest marine environments. But the difference in temperature between the water and the air had a strange effect on Peru’s climate. As the sea winds blew over the hot dry land, the air masses warmed up. This increased their capacity to absorb moisture and so, instead of dropping moisture, they sucked up more as they continued inland. The boundaries between warm and cold, between wet and dry — they created life and destroyed it. Humboldt decided to map his discovery.
ISOLINEAR MAPS
Isolines are lines connecting points of similar information. Places where people prefer tea over coffee, for example, might produce a line between England and China — which would be very useful for anyone selling tea.
The first time isolines appear on a map is in 1686, when British astronomer Sir Edmond Halley (after whom Halley’s Comet is named) drew lines connecting points with similar compass readings to produce the first map of magnetic force fields. In 1 791 a French mapmaker, J. Dupain-Triel, used isolines to connect similar levels of land above sea level, and made a topographical map. Alexander von Humboldt used isolines on maps he made after his trip to South America, connecting points where the temperature was the same. Because they join points of the same temperature, Humboldt’s isolines are really isotherms. In fact, he made the first isothermic map, better known as a weather map.
In 1804, the two naturalists sailed for home, carrying thirty packing cases of some 60,000 species of plants, birds, and beasts. In Europe they were hailed as scientific giants. Bonpland was made head of the botanical gardens in Paris, but eventually returned to South America. As for Humboldt, he spent his family fortune on other
expeditions, and on writing and publishing thirty-three books. His unfinished, five-volume Kosmos was one of the best-selling books of the 19th century. Humboldt also produced 1,426 maps, including new thematic maps of ancient civilizations, crops, and weather.
Humboldt was a proud man. But he was never comfortable when people called that cold Peruvian current that teemed with life the Humboldt Current; he preferred it to be called the Peru Current. Still, traces of his name are scattered across the Americas: Humboldt mountains, Humboldt counties, and at least eight towns named in his honor. But Humboldt, who lived to be almost ninety, always said that climbing Mount Chimborazo was the greatest honor of all. “Of all mortals,” he gloated genially in his old age, “I was the one who had risen highest in the world.”
THE MAPMAKERS’ SENSE OF THE LAND
Mapping North America
AS THE WINTER of 1804 closes in over the Dakota plains, the temperature drops to more than 40° below freezing. Captains Meriwether Lewis and William Clark, and their team — the Corps of Discovery — decide to pass the coldest months in the snug, earth-covered lodges of the Mandan people on the banks of the upper Missouri River.
The Mandan share their lodges with horses and dogs, and even occasional white visitors. In 1798, a Canadian fur-trader and explorer named David Thompson had wintered with them. Now, six years later, it is Lewis and Clark, wrapped in thick bison robes, who sit along with their men around the Mandan campfires.
Just as Thompson had, the Americans question the Mandan about the lands to the west. They examine maps painted on bison hides, and ask the Mandan to draw more maps. Sometimes their hosts use pointed sticks in the campfire ashes. Sometimes they borrow Clark’s pen (he is friendlier than Lewis, who seems remote and moody) and sketch great branching rivers on scraps of paper.
The Mandan don’t realize who they are helping. President Thomas Jefferson, son of a land surveyor, has sent out the Corps of Discovery to claim western North America for the United States. The fact that people such as the Mandans have lived there for thousands of years doesn’t matter, since they have no officially recognized maps or surveys giving them legal claim. Lewis and Clark have come to survey the land for settlement by white people.
MAPPING OFF PAPER
The peoples of Africa, Australia, the far north, and the Americas did not produce paper charts, for a simple reason: such maps weren’t useful to them.
The Ammassalik people of Greenland had to find their way in a land that is dark in winter months, where they couldn’t walk in a straight line from A to B if the ice in between was treacherous or the way blocked by huge ridges of snow. For them, paper maps of fixed positions would have been useless. So they developed the right kind of map for their landscape and their way of life. They carved the outlines of their land, its cliffs and bays and hills, onto pieces of wood. These relief maps could be read by feel, in the winter darkness or in a blinding snowstorm.
Many of the Native peoples encountered by European explorers in North America were nomadic hunters. It would make no sense for them to draw the outlines of their territories, because the outlines were always shifting as they moved through the land following animals for food. It made more sense to use “mental maps” — songs and stories — to tell about routes and the locations of dangers, good hunting grounds, and sacred places. Then they could tell these stories to guide their families on their way.
Nomadic peoples could produce cartographic maps if they wanted to. The great French explorer of North America Samuel de Champlain reported in 1611 that the Native people along the St. Lawrence River “told me many things, both of the rivers, falls, lakes and lands, and of the tribes living there … showing me by drawings all the places that they had visited.”
On November 11, 1804, Clark writes in his journal about the arrival in Mandan lands of a fur-trader from Montreal, named Charbonneau, and his teenage wife. This girl, a Shoshone, was kidnapped when she was about eleven by the Hidatsa people, who sold her to the fur-trader. Now she is pregnant. Her name is Sacagawea.
Lewis and Clark size up Charbonneau, and decide he is shifty and bad-tempered. But they figure that his wife might be useful as an interpreter when their expedition gets to Shoshone country. They offer to hire Charbonneau for the journey west — if he brings along Sacagawea.
The Mandan were not suspicious of the white mapmakers because they didn’t even think of the land, or use it, in the same terms as Europeans. For Native peoples, land was to be hunted in, traveled over, and praised. “What is this thing you call property?” Massasoit, a chief of the Wampanoag country, had asked colonists in the place the newcomers called New England. “It cannot be the Earth, for the land is our mother. The woods, the streams, everything on it belongs to everybody. How can one man say it belongs only to him?”
For Europeans, land was something to be controlled, divided up, sold, taxed, and developed. Land hunger was one big reason why the United States was born. In 1763, when King George III of England ordered colonists to stop settling west of the Appalachian Mountains, the colonists rebelled. After the Americans gained independence, they realized that if they didn’t plant their flag in the west, the British would. The British had been sniffing around ever since James Cook and George Vancouver hoisted the British Union Jack along the Pacific Coast in the 18th century.
Today’s map of Lewis and Clark’s North America.
There were British explorers moving in by land, too — such as Alexander Mackenzie, a Scots-Canadian mapmaker and fur-trader. Guided by Nuxalk Natives, he traveled down the Bella Coola River to the Pacific at the end of the 18th century. To impress other Europeans that he was the first European to cross the continent, he fixed his position by latitude and longitude and, on a rock overlooking the Pacific, used vermilion and grease to paint this sign: Alexander Mackenzie from Canada, by land, the 22nd of July 1793. On his return to England, Mackenzie wrote a book about his achievement. American President Thomas Jefferson read it with great interest, aware that other Canadian fur-traders were planning on following Mackenzie. In 1801, David Thompson, who knew Mackenzie, had already tried to find a way through the Rocky Mountains near present-day Banff, Alberta. So it was with a sense of urgency that Jefferson ordered Lewis, Clark, and their team of forty men to set sail from St. Louis, Missouri, in May 1804.
The group included Clark’s slave — a man named York — and several Mêtis woodsmen — part French-Canadian, part Aboriginal. The groups mission was to explore the west, to find an overland route to the Pacific, and to note which lands would be good for settlement. They brought along rough maps of the regions into which they were heading, which showed one ridge of mountains and about 3,000 kilometers (2,000 miles) of unmapped land between themselves and the Pacific. They figured the trip would take about a year.
As they sailed up the river, the Corps of Discovery would stop at Native villages and call a council. To impress everyone, the Americans showed off their magnets, spyglasses, and guns. Then they would smoke pipes, and trade needles and buttons in exchange for food and information. York was part of the show too — he had to stand around and let Native people who had never seen a black man before run their curious hands over his kinky hair and dark skin.
Sometimes the expedition passed deserted villages. Already, contact with European fur-traders had brought smallpox to the west, and thousands of Native people had died. Still, the people along the Missouri could see that Lewis and Clark, with their questions and peace pipes and trading goods, weren’t on a war mission. Besides, Clark used his skills in Western medicine to cure the sick.
In February 1804, in the middle of their long winter with the Mandan, Clark used those skills to help Sacagawea give birth to a little boy named Jean-Baptiste. Before the baby was two months old, spring came and lifted the ice from the Missouri River. The Mandan village began to stir with rumors that British fur-traders were riling up Native people against the Americans. They heard news that the Spanish of New Mexico, fearing that the Americans would t
ake over Spanish territory, and had sent a raiding party of fierce Comanches to stop them. It was time to get moving.
As seen on this one-dollar American coin, Sacagawea was a young mother. There are more statues of Sacagawea in the U.S. than of any other woman. She is usually shown pointing west.
Sacagawea strapped the baby onto a cradleboard, hoisted him on her back, and followed the expedition up the river into what is now Montana. They sailed past huge herds of bison and astonishing rock formations. Wherever they landed, the new mother helped out by finding prairie roots and berries to add to the expedition dinners.
On May 14, a sudden squall tipped the boat, and dumped the expeditions equipment, medicines, journals, and trading goods into the river. Charbonneau panicked, and another Métis threatened to shoot him if he didn’t calm down. Meanwhile Sacagawea quietly collected the floating equipment and laid it on the bank to dry. Lewis wrote, “The Indian woman, to whom I ascribe equal fortitude and resolution with any person … caught and preserved most of the articles.” A few weeks later, Sacagawea fell ill. Clark nursed her with a rich soup made of bison meat.
The explorers were starting to realize that the west was far more vast than their rough maps had indicated. They charted as they went, making notes about the landscape’s beauty (“The hills we passed today exhibit a most romantic appearance”), but they realized with sinking hearts that there was no chance of reaching the Pacific and returning home again within a year.
By midsummer they came to the Missouri headwaters — the rivers beyond flowed westward to the Pacific. On July 22, Sacagawea cheered up everyone by announcing that she recognized Shoshone country. Lewis (who was a terrible speller) wrote in his journal, “She is our only dependence for a friendly negociation with the Snake [Shoshone] Indians on whom we depend for horses to assist us in our portage from the Missouri to the Columbia river.”
