Charles Marie de la Condamine - First Scientist in the Amazon

Charles Marie de la Condamine was a French explorer, physicist, geographer and mathematician born in Paris on January 28, 1701.  His early interests in science led to his participation in the most important scientific mission of the times: in the early 1730’s there was a dispute as to whether the earth was wider around the equator or around the poles.  Sir Isaac Newton argued the Earth was wider around the Equator; the French geographer Cassini argued otherwise.

The King of France and the French Royal Académie des Sciences sent two teams to find out the answer, one to Lapland and another to South America.  La Condamine, as a young and promising member of the Académie des Sciences, became a part of the mission that was sent to South America by that body in 1735 to establish the length of a degree of the meridian in the vicinity of the Equator, so that it could be compared to the length of a meridian in Lapland and thus answer the question; this work also laid the foundation for the determination of the length of a meter.

The group also included Louis Godin des Odenais, Pierre Bouguer, and two officers of the Spanish marine, Antonio de Ulloa, and Jorge Juan y Santacilia. The latter two represented the Government of Spain on the journey and also made independent observations in the interior.  They landed in Colombia and journeyed overland to Panama, then sailed to Ecuador. A local governor and scientist-mathematician, Pedro Vicente Maldonado, traveled through the rainforests with Condamine. They sailed up the Esmeraldas River and then went up the Andes Mountains, arriving in Quito on June 4, 1736.

Condamine’s mandate was to find out the shape of the earth by using a meridian and thus ascertaining the flattening of our globe toward the poles. Once in Ecuador he began his work, establishing a base line and making a reasonably accurate triangulation of the precipitous parts and the western sections of Ecuador. There he made one of his discoveries, that high mountains deflect the pendulum by their attraction.

Condamine, Godin and Bouguer were soon involved in disagreements. They finished their measurements by 1739, measuring the length of an arc of one degree at the Equator, but they got word that the Lapland expedition had already finished their work and had proven that the Earth is flattened at its poles. The three went their separate ways, and in 1743 Condamine began his return trip.  The others chose to return to Europe by way of the better known route from Ecuador to Panama and by ship to Europe.  Condamine decided to follow the longer yet more scientifically interesting path of crossing the Andes and entering the Amazon basin from the east, with a four-month raft voyage down the Amazon River.

The route Condamine chose began at the furthest traversable reaches of the Marañón River and went on through the treacherous pass at Pongo of Manseriche for the express purpose of seeing the pass. Traveling on a raft built by his guides, Condamine had quite a few close calls not only with his life but also the eight years of research and scientific instruments he was carrying back to France.

After passing through Pongo of Manseriche where the river narrowed from 1500 to 150 feet across, Condamine again almost lost his raft and work before emerging out of the mountains and onto the flat plain of the Amazon Basin. The raft arrived at a settlement on the river at Borja, where a priest provided him with a map of the area and accompanied him for the next portion of the voyage.

The expedition changed from rafts to two large canoes at Borja, each 44 feet long and 3 feet across. La Condamine must have felt safer in the new canoes with rowers paddling day and night, because he took up the task of measuring and mapping the river. In late July the group arrived at the spot where the large Ucayali River meets the Amazon and Condamine observed the Omaguas, a tribe first stumbled upon by the missionary Padre Fritz years before.

Several explorers of the New World in the preceding two centuries had brought back news of native poison-tipped arrows that brought speedy death by paralysis. These lethal arrows were generally used for hunting animals, and they were occasionally used against the European explorers and soldiers. Natives called the toxic herb ourari, which became curare to the Europeans. Condamine collected samples of the curare and brought them back when he returned to France.  He also discovered that curare was only poisonous when in contact with blood; it could be ingested without consequences, as many native foods included the same ingredient.

He also noted local rubber production techniques, calling the substance caoutchouc after the local term for weeping wood. Caoutchouc was named “rubber” in the 1770s after English scientist Joseph Priestley noticed that the substance could be used to erase pencil marks from paper. American inventor Charles Goodyear discovered vulcanization (a method of treating rubber to make it strong and elastic) in 1839 when he unintentionally dropped a combination of rubber and sulfur on a hot stove.

Condamine sent back some rolls of crude rubber in 1736, together with a report of the products manufactured from it by the people of the Amazon Valley. General scientific interest in the substance and its properties was revived. In 1791 the first commercial application of rubber kicked off when an English manufacturer, Samuel Peal, patented a method of waterproofing cloth by treating it with a solution of rubber in turpentine.

Natural rubber for commercial use is taken almost exclusively from Hevea brasiliensis, a tree native to South America, where it grows wild to a height of 34 meters (120 feet). Hevea only grows within a well-defined area of the tropics and subtropics where frost is never encountered.

As an explorer and physicist Condamine ranks very high, though because of his ambition and inclination to controversy he was a disagreeable character. The topographical work done by him or under his direction suffered from the comparative imperfections of the instruments in use at his time, but the results obtained were amazing. Not only in physiography and physical geography, but in other branches also his mission opened a new perspective to investigation.  Father Fritz´s maps, the only available of the Amazon at the time, were corrected by Condamine and Condamine´s version closely resembles today´s Amazon.

He stayed in South America for ten years, and wrote excellent descriptions of his travels, notably the Journal d’un voyage fait par ordre du roi à l’équateur.  He is considered the first explorer to visit the Amazon in search of knowledge and for scientific reasons.  Previous visitors did so either in search of wealth (El Dorado) or souls (Jesuits).

Baron Alexander von Humboldt –The Last Renaissance Man

Alexander von Humboldt was one of the first persons to move geographical studies from the ancient into the current era. The Prussian natural scientist and geologist traveled around a great deal of South America, studying the environment, mountaineering and monitoring astronomical events. His contributions to science spanned biology, geography, climatology, geology, hydrology, among others. Charles Darwin called him “the greatest scientific traveler who ever lived” and he is widely considered to be the last renaissance man, who could gather within himself a substantial portion of human knowledge.

Humboldt was born into a noble family in Berlin on September 14, 1769, of German and French Huguenot parentage. While he was still a boy his father, an army officer, died. The young Humboldt studied at the universities of Frankfurt an der Oder and Gottingen from 1787 and later went to the School of Mines at Freiburg in Saxony. While there he studied under the famous geologist A.G. Werner. He became wealthy enough to plan a 5-year period of exploration after his mother’s death in 1796.

The household was marred by his mother’s “cold and aloof” nature. A private tutor educated Humboldt and his brother, Wilhelm, who turned out to be a distinguished economist with worldwide fame as well that lives to this day. Humboldt never married but derived great joy from friendships with colleagues and others and also from his brother’s friendly household. In 1792 he joined the mining department of the Prussian Government and promotion came quickly given his brilliance and dedication.

Humboldt sailed from A Coruna, Spain on June 5, 1799, armed with powerful recommendations from the Spanish king, and headed for Caracas. At that time Spain was preoccupied with the pursuit of wealth and conquest in its American colonies. In February 1800 he left the Venezuelan coast for the purpose of exploring the course of the Orinoco River. Four months and 1725 miles of uncultivated and unoccupied country later, while traveling by foot and canoe, Humboldt established the existence of a communication between the water systems of the Amazon and Orinoco Rivers.

This bifurcation, known as the Casiquiare Canal, is the only place in the world where two river systems that flow in different directions (the Orinoco goes north and the Negro/Amazon flows southeast) have any kind of fluvial communication.  The existence of this canal was a rumor dismissed as impossible by European geographers at the time.  Catholic priests had originally reported it, but provided no scientific evidence to it in the early XVIII century.

It was a tremendously dangerous environment with alligators, jaguars and swarms of biting insects, aside from numerous uncontacted tribes that are today recognized as the Yanomami. At times he and his traveling companion, botanist Aime Bonpland, had no food, and conditions were almost unbearable. Still isolated, still unwelcoming, still undeveloped, this wild region is little changed today.

Humboldt and Bonpland collected over 60,000 plant, animal and mineral specimens and still found the time to study electricity. They were the first Europeans to discover an animal that produces electricity: Electrophorus electricus, the electric eel.

To obtain electric eels for carrying out tests, he and his helpers drove about 30 horses into an eel-infested lake, trapping the horses there to be shocked repeatedly until the frantic eels exhausted themselves and posed little danger to the humans. Two tormented horses drowned in the first five minutes. They were vindicated somewhat when a not-quite-exhausted eel later shocked Humboldt. In fact, Humboldt freely subjected his own body to agonizing electrical experiments, including gripping an eel in one hand and a piece of metal in the other to expand the electric charge.

Humboldt´s explorations in the Casiquiare Canal and upper Rio Negro made him the second scientific explorer in the Amazon, following La Condamine.  Unfortunately, the Portuguese rulers were so afraid of the new ideas and “hidden intentions” of Humboldt´s mission that there was an order in the Marabitans fort for his arrest if he entered Portuguese territory (in Brazil today).  As he was unable to proceed down the Rio Negro to meet the Amazon river, he turned back and journeyed to Cuba, the Magdalena River Basin of Colombia, and the Andes Mountains of Ecuador.  There, where he climbed the volcano Chimborazo to an elevation of more than 5800m (19,000 feet) above sea level to study the relation of temperature and altitude.  He was recognized at the time as the record holder of altitude in the world, when Europeans had only climbed Mont Blanc, a much smaller mountain.

Humboldt established the use of isotherms in map-making, studied the origin and course of tropical storms, and made pioneer investigations in the relationship between geographic environment and plant distribution. He measured and discovered the Peruvian Current, which, over the objections of Von Humboldt himself, is also known as the Humboldt Current. He made observations leading to the discovery of meteor shower periodicity, and examined the fertilizing properties of guano. His review of the political and historical characteristics of South America, Mexico and the Caribbean are also noteworthy.

South America was a virtually unknown land, and much of what Humboldt observed was new knowledge. He tirelessly recorded his observations, no matter where he went or what he did. This proved to be his greatest legacy. He published more than 30 volumes of facts between 1805 and 1827, proving his brilliance as a writer and artist.

Humboldt once said, “devoted from my earliest youth to the study of nature, feeling with enthusiasm the wild beauties of a country guarded by mountains and shaded by ancient forests, I have experienced in my travels, enjoyments which have amply compensated for the privations inseparable from a laborious and often agitated life.”

Another notable quote from Humboldt is, “One of the noblest characteristics which distinguish modern civilization from that of remoter times is, that it has enlarged the mass of our conceptions, rendered us more capable of perceiving the connection between the physical and intellectual world, and thrown a more general interest over objects which heretofore occupied only a few scientific men, because those objects were contemplated separately, and from a narrower point of view.”

In his time, von Humboldt was an explorer and scientist of incomparable renown, and his work largely inspired Charles Darwin and influenced the course of a number of scientific disciplines. Humboldt’s Cosmos, a biography written by Gerard Helferich, retraces the 1799-1804 odyssey of von Humboldt through Central and South America while merging the various stories written about the explorer into a succinct appreciation of his character and scientific significance.

Humboldt became an international celebrity after he self-published a sequence of publications about his travels in the Americas. These publications were extremely popular and were translated into many languages. They contained radical beliefs for the time, such as Humboldt’s judgment that the indigenous peoples of Africa and the Americas were in every respect equal to those of any other part of the world.

As the first biologist to draw attention to the unifying aspects of the physical world, von Humboldt can be considered the first conservationist to support ecological balance, a concept that was at variance with mainstream science’s view of a “chaotic world” and preoccupation with specialization. Besides being Darwin’s mentor, von Humboldt’s inflence also extended to Simon Bolivar, the Latin American hero.

During the final years of his long life Humboldt wrote a five-volume work, Kosmos (The Cosmos, 1845-1862) in which he described not only his infinite scientific knowledge but also most of the accumulated scientific knowledge of geography and geology at the time. Kosmos has been called the first textbook of geophysics. Humboldt died in Berlin on May 6, 1859.

Lope de Aguirre - The Mad Conquistador of the Amazon

Lope de Aguirre was a Spanish Basque conquistador in South America. He was born around 1510 in Araotz Valley, in the Basque region of Guipúzcoa, part of the Kingdom of Castile in present day Spain.

Wonderful news of the treasures of Peru were reaching Seville during the early 1530s.  Hernando Pizarro arrived with a fifth of the royal treasure of the uncrowned Inca chief Atahualpa: bars of gold and silver, diadems, sheets of precious metal, sacred vases, idols and plates. News spread across Spain and adventurers, Aguirre among them, flocked to Seville, where expeditions were put together.

Aguirre joined a team of 250 men selected by Rodrigo Buran, and they arrived in Peru in 1536 or 1537. He worked alongside Peru’s first viceroy, Blasco Núñez Vela, who arrived from Spain in 1544 with orders to put into practice the New Laws, stifle the Encomiendas (a system where conquistadors were granted trusteeship over the indigenous peoples they conquered), and release the natives.

The conquistadors did not like these laws, particularly because they barred them from taking advantage of the Indians. In 1551 the judge Francisco de Esquivel arrested Aguirre and charged him with violation of the laws for the protection of the Indians. The judge discounted Aguirre’s reasons and his claims of gentry and sentenced him to a public whipping.

Aguirre was so enraged with the punishment he publicly vowed to take revenge upon the judge.  The judge fled after his mandate ended, changing his residence constantly. Aguirre pursued him on foot to Lima, Quito, and then on to Cuzco. In three years he ran 6,000 km by foot, unshod, on the trail of Esquivel. Aguirre found him in Cuzco at last, in the house of the magistrate; while Esquivel was having a siesta in the library, wearing a coat of mail he always wore for fear of Aguirre. Aguirre cut his temples.

He took part in the civil wars among the Spanish conquistadors in Peru after Francisco Pizarro occupied that country in 1533. In 1559 he joined an expedition to search for the renowned El Dorado. The expedition was led by Pedro de Ursúa, a gentleman, who was charged with confirming Orellana´s discoveries and searching for the El Dorado and other riches such as cinnamon.  They initiated their mission down the Marañón and the Amazon river.  Aguirre put together a group of conspirators and ousted and murdered Ursúa along with his wife.  They initially placed Fernando de Guzmán as leader, but soon thereafter Guzman was also murdered by Aguirre. 

Their initial mission was to reach the Atlantic through the Amazon delta, yet Aguirre changed the mission to return as a rebellious group into Peru and take over its riches.  It is unknown whether Aguirre was able to take a shortcut back through the Casiquiare canal into the Orinoco river and present day Venezuela or if he actually completed the mission through the Amazon, following currents that led him back to the Caribbean.  Along the way, Aguirre and his men terrorized and destroyed native villages.

During the journey Aguirre relinquished allegiance to the king and sought to return to Peru to set up an empire there that would be independent of Spain.

Aguirre, the Wrath of God is an independent 1972 German film written and directed by Werner Herzog about Aguirre. The story follows Aguirre’s travels as he leads a group of conquistadors down the Amazon River in search of the legendary city of gold, El Dorado. This was the first of five film alliances between Herzog and the explosive lead actor Klaus Kinski. Aguirre opened to widespread critical acclaim, and rapidly developed a huge global cult following.

Noted film critic Roger Ebert describes the film as “one of the great haunting visions of the cinema.” The haunting, ecclesiastical music sets its tone. Herzog doesn’t rush the conquistadors’ voyage, or fill it with artificial episodes of suspense and action. Ebert compares the film to 2001: A Space Odyssey, and Apocalypse Now, and describes Herzog as “the most visionary [of modern filmmakers] and the most obsessed with great themes.”

Lead Klaus Kinski was “made to play villains,” says Time Magazine. In this film, he depicts Aguirre’s madness as he tries to tame the wilds of Peru with almost frightening believability. Aguirre’s crew, under assault from the natives, had gone mad too. “That is no arrow,” one crewmember says in the film. “We only imagine the arrows because we fear them.”

The film follows the same journey that Aguirre takes, quiet at first, and pleasantly mysterious. The jungle grows increasingly hostile as the film progresses. We learn from a local Indian that this wilderness goes on forever. He cautions Aguirre, “God, in his anger, never finished this place.” This comes long after the opening narration informs us that El Dorado is and always has been a ruse invented by the Indians to drive Europeans, who the Indians now know are clearly not gods, deeper and deeper into the wilderness.

In 1561, at the end of his failed mission along the Amazon, Aguirre wrote a letter to King Philip II, which rejected the discovery and invention of America as the object of European mythical aspirations. This small piece of protest is considered the most radical of the reports, dispatches and chronicles sent to Spain from the colonies. Aguirre openly blames the king for deserting him and not respecting the old promises of mutual service.

The letter begins, “From Lope de Aguirre, your lesser vassal, old Christian, of middling parents but fortunately of noble blood, native of the Basque country of the kingdom of Spain, citizen of the town of Onate,” and continues, “I demand of you, King, that you do justice and right by the good vassals you have in this land, even though I and my companions (whose names I will give later), unable to suffer further the cruelties of your judges, viceroy, and governors, have resolved to obey you no longer.

“I am certain there are few kings in hell because there are few kings, but if there were many none would go to heaven. Even in hell you would be worse than Lucifer, because you all thirst after human blood. But I don't marvel nor make much of you. For certain, I and my 200 harquebus-bearing maranones, conquistadors and noble, swear solemnly to God that we will not leave a minister of yours alive, because I already know how far your clemency reaches.”

Aguirre seized Isla Margarita in 1561 and cruelly suppressed any resistance to his reign. His open mutiny against the Spanish crown came to an end when he crossed to the mainland in an attempt to take Panama. He killed his own daughter Elvira when he was surrounded at Barquisimeto, Venezuela, “because someone that I loved so much should not come to be bedded by uncouth people.”

Aguirre was eventually captured and shot, and his body was cut in quarters and sent to various cities across Venezuela.

Francisco de Orellana - A brief history of the first explorer of the Amazon

Francisco de Orellana was a Spanish explorer and conquistador. He may have been a relative of Francisco Pizarro, the conquistador of Peru. Like his Pizarro relatives, Orellana was born in Trujillo, Estremadura. He reached the New World as a teenage boy and participated in the Pizarro conquest of Peru, where he lost an eye in battle. He was one of Gonzalo Pizarro’s lieutenants during his 1541 mission across the Andes Mountains east of Quito into the heart of South America in quest of El Dorado and the Country of Cinnamon.

They faced tremendous challenges overcoming the Andes, leaving from Quito, when they finally arrived at the Napo River, one of the Amazon river´s tributaries that lead to the Amazon basin lowlands.  They faced Indian attacks and captured many, who under duress kept confessing to there being a land of gold and nutmeg downriver.  After weeks of hardship and with their food reserves running low (by this time they had eaten their horses and dogs), Orellana was ordered by expedition leader Pizarro to sail downriver in search of food and signs of treasure and then return.

Orellana was chosen because he knew many native languages, and could communicate with the Indians and get help. But he and his men didn’t find any villages while navigating the Napo River. Instead, they suffered so much hunger they ate their own shoes.

He descended the stream to its junction with the Amazon River, in present-day northeast Peru; instead of returning, as he had promised Gonzalo Pizarro, he proceeded down the river to the Atlantic Ocean. Orellana managed to navigate the length of the Amazon in one of the most surprisingly successful expeditions in known history, arriving at the river’s mouth on August 24, 1542.  He then managed to follow sea current up the coast of South America, finally reaching the Caribbean and Isla Margarita in Venezuela, from where he was taken to Spain to meet the king and tell of his amazing journey.  He is known as the first European to descend the Amazon river.

Chaplain of the expedition, Gaspar de Carvajal, wrote a diary of their voyage, which provides interesting, if not always accurate, descriptions of what the Amazon was like before Europeans arrived.  He describes fertile croplands and turtle farms in the heart of the Amazon Basin. Long thought to be exaggerations, attitudes to Orellana’s claims are beginning to change. His description of continuous riverside human settlements are slowly being met by the archeological record, showing that the Amazon is a place that can sustain large human agglomerations, as long as the appropriate technology for sustainability exists. 

He may have well led the first party of Europeans through a greatly advanced civilization that thrived in the Amazon for centuries – a civilization whose existence was thought to be impossible. 

The excavation of ruins and even fragments of the language of Amazonians with words for crops they were supposedly unable to farm suggests that there were complex agricultural practices in place thousands of years ago.

Archaeologists have found that these Amazonian farmers apparently developed raised fields over half-mile long with irrigation canals in between. Somehow they found a method to enrich the soil with a microorganism that creates a dark, loamy stratum with potting-soil like qualities. Up to 10% of the Amazon Basin has been terra-formed in this manner by the ancients – an area the size of France.

A Spanish expedition in 1617 remarked on the extent and high quality of a network of raised causeways connecting villages in the Amazon together. These causeways can still be seen as straight lines cutting across the savannah. Alongside them run canals, the result of their construction. This canal network could have sustained hundreds of thousands of people, and archaeologists believe that this area was home to a society that had totally mastered its environment.

During his voyage, Orellana also described encountering a tribe of women very white and tall and doing as much fighting as 10 men. These warrior women were very skilled with bows and arrows, and their queen, Conori, was said to have great treasures. Their formidable strength brought to mind the Amazons of Greek mythology, and Orellana’s tales of these female warriors gave the river and the region its name.

Orellana’s own name remains a bit stained owing to the suspicion that he abandoned Pizarro in a desperate situation. However, his men testified and he was found innocent. When he returned to Spain, Orellana sought and obtained a dispensation to explore and rule New Andalusia, meaning roughly the land south of the great river. He sailed from Sanlúcar on May 11, 1545, with an inadequately outfitted fleet and accompanied by his wife, Ana de Ayala, whom he had married in Spain. 

After being appointed governor of New Andalusia, he and his men arrived at the Amazon river delta, built a riverboat and explored 500 km of the region. They faced many hardships and of the 300 men he had taken with him from Spain only 44 were rescued at sea by another Spanish fleet.  Orellana was one of the casualties – he died in November 1546.

The Amazon is the world’s second-longest river at 3980 miles. Its collects water from 40 percent of the continent, in the form of thousands of tributaries, many of which are more than 1000 miles long. As with the Nile, the people who lived in the Amazon in ancient times used the river for agriculture and transportation.

There is now an inland province of Ecuador named Orellana, the capital of which is Puerto Francisco de Orellana. The province is named after Orellana, who is said to have sailed from somewhere near the town to the Atlantic Ocean. He did this trip several times looking for El Dorado and a rumored nutmeg forest, nutmeg at the time being a very expensive spice.

Orellana, fanatical as he was with finding gold, was known as the “Gilded Man.” He claimed to have seen the glittering El Dorado, stories of which still reverberate through the archaeological community, and while it is perhaps easier to believe that Orellana was a fraud, there are still those who look for remains of the past that might confirm that the legendary city did exist.

The legend of El Dorado apparently originated in a tradition of the Chibcha people of Colombia who each year selected a chieftain and rolled him in gold, which he then ceremonially washed off in a sacred lake, casting offerings of emeralds and gold into the waters at the same time. This custom had evidently vanished long before the coming of the conquistadors, but the tales lived on and grew into a legend of a land of gold and plenty.

Orellana’s exploration also produced an international issue between Spain and Portugal because, according to the Treaty of Tordesilhas, the delta of the Amazon should be ruled by Portugal. It would only be resolved a century later with the exploration of Pedro de Teixeira.

Alfred Russel Wallace: Great Explorer and Discoverer in the Amazon

Alfred Russel Wallace was a British natural scientist, explorer, geographer, and anthropologist. He did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the Wallace Line dividing the fauna of Australia from that of Asia. He is best known for independently proposing a theory of natural selection, which prompted Charles Darwin to publish his own theory. Wallace is considered co-discoverer of the theory.

Wallace was the eighth of nine children, born on January 8, 1823 at Usk, Monmouthshire. He was educated at Hertford Grammar School and left at the age of 14. In 1844 Wallace became a schoolmaster at the Collegiate School in Leicester, where he met the naturalist Henry Walter Bates. Wallace convinced Bates to join him on an expedition to the Amazon to collect specimens.

Before leaving for the Amazon, Wallace gave himself an intensive crash course in flora and fauna, making local collecting trips and haunting the British museum. For Bates and Wallace, who sailed in 1848, the jungle was their university, as well as a source of income. Growing interest in natural history was creating a dynamic market in reports and samples from the field. A practice that today would be considered biopiracy was then common and the only sustenance available to fund poor scientist doing field research across the world.

Wallace and Bates signed on with an agent, Samuel Stevens, who taught them taxidermy and species preservation, planned their itinerary to accord with the needs of collectors, sent them bottles and cash when they ran out, and advertised their findings in specialized journals, selling their specimens to institutions like the British Museum and Kew Gardens, as well as to wealthy amateurs.

The two naturalists spent their first year collecting near Belem do Para, then explored inland separately, occasionally meeting to discuss their findings. Another young explorer, botanist Richard Spruce, along with Wallace’s younger brother Herbert, briefly joined them. Wallace charted the Rio Negro for four years, collecting specimens and making notes on the people and languages he encountered as well as the geography, flora and fauna.

Wallace noted that range boundaries for a number of animal species in the Amazonian rain forest seemed to coincide with the region’s many rivers. That observation marked the origin of one of the foremost theories for why the Amazon harbors such extraordinary biodiversity for its size. This “riverine border hypothesis” in its modern form posits that the Amazon’s main rivers functioned as natural barricades to gene flow between populations.  Such thoughts were precursors and complementary to his findings in the Malay Archipelago, where species differentiation across islands finally drove him to conceive the theory of natural selection.  The Amazon was the first instance of thinking of species differentiation due to physical boundary, be it because of rivers or islands.

In his publication titled Tropical Nature and Other Essays, Wallace notes that,

Warning colours ... are exceedingly interesting, because the object and effect of these is, not to conceal the object, but to make it conspicuous. To these creatures it is useful to be seen and recognized; the reason being that they have a means of defence which, if known, will prevent their enemies from attacking them, though it is generally not sufficient to save their lives if they are actually attacked.

By early 1852 Wallace was in ill health and in no condition to go any further. During his travels back downriver, his canoemen plotted to kill him and take over his belongings.  Since he had been in the Amazon for so long, he had learned Portuguese and could overhear their plot at night, from which he escaped by “convincing” his men at gunpoint to paddle back to Barra do Rio Negro.

He decided to quit South America, and began the long trip back down the Amazon river to Para. To Wallace’s dismay, he found that not only had his brother Herbert died of yellow fever, but most of the collections from the previous two years that he had been forwarding down the Amazon had been delayed at the dock at Barra do Rio Negro because of a mix-up, he would therefore have to secure passage for these as well as himself.

He soon set out for England, but unfortunately, the brig on which he was traveling caught fire and sank, taking almost all of his possessions – including some live animals, along with it. For ten days Wallace and his comrades struggled to survive in a pair of badly leaking lifeboats, then were sighted and picked up by a passing cargo ship also making its way back to England.

He was distraught after arriving in England with none of his notes and collections of six years of hard labor within the forest, but he was able to recover parts of his work from memory or from collections previously sent.  He lived on the insurance settlement for his collection for eighteen months, during which he vacationed in Switzerland, attended professional meetings and delivered papers, and produced two books, Palm Trees of the Amazon and their Uses, and A Narrative of Travels on the Amazon and Rio Negro. He also wrote six academic papers, which included Monkeys of the Amazon.

Wallace published several other books, including:

• Darwinism
• Miracles and Modern Spiritualism
• My Life: A Record of Events and Opinions
• The Evidence of Literary and Professional Men to the Facts of Modern Spiritualism
• The Moral Teachings of Spiritualism
• The Old Force, Animal Magnetism and Clairvoyance

In an article titled The Dawn of a Great Discovery, Wallace speaks of how, after his return from the Amazon he was, in 1854, preparing for his visit to the Malay Archipelago for a study of insects and birds of that region, when one day, he was introduced to Darwin in the insect room of the British Museum, and had a few minutes conversation with him.

Hearing that Darwin was interested in his travels and collections, Wallace wrote to him afterwards and received a very long letter in reply, telling him that he agreed with almost every word of his article. The two men agreed on the subject of evolution, and Wallace’s article prompted Darwin to publish his own theory on “The Origin of the Species.”

Wallace married Annie Mitten in 1866, after being introduced to her by Richard Spruce, who was a good friend of Miss Mitten’s father, William Mitten, an expert in mosses. The Wallaces had three children, Herbert, who died in childhood, Violet and William. On November 7, 1913 Wallace died at home in a country house he called Old Orchard. He was 90 years old.