The Science of the Lewis and Clark Expedition

It has been described as "the greatest camping trip of all time," a voyage of high adventure, an exercise in manifest destiny which carried the American flag overland to the Pacific. The Lewis and Clark Expedition was all of this and more. However, it is astounding that the expedition is so rarely talked about in terms of its scientific achievements. It is as though the popular image of Lewis and Clark has come to coincide with the image Spanish bureaucrats had in 1804. The Spanish were skeptical that the expedition's announced "scientific" goals were anything but a smokescreen for a blatant march across territory they claimed in the name of His Catholic Majesty. Today, the Lewis and Clark Expedition should be celebrated for what it was - and this includes the fact that it was one of the first systematic scientific evaluations of a region ever conducted. Most scientists understand this aspect of the story, but the general public is often baffled by all that scientific jargon and those long, boring, copious notes on plants, animals and geology cut out of most early published versions of the journals. It is the fact that the findings of Lewis and Clark went unpublished for so long that often keeps them from being considered for their scientific work.

Also, President Thomas Jefferson's penchant for secrecy and duplicity does not help accentuate the importance of this scientific work for the modern reader. He soft-pedaled the scientific aspects of the expedition even as he asked Congress for money. The purposes of the expedition were twofold, Jefferson claimed, but only the first purpose was of any real consequence - the diplomatic mission of contacting Indian nations, establishing the United States as sovereign over the region and as a major player in the fur trade. He made the second purpose, the scientific one, seem like an inconsequential afterthought. Jefferson knew that diplomacy, especially with the goal of increased commerce, could be sold to Congress; scientific discovery and description could not. One seemed practical, the other less so.

Yet, as Jefferson wrote letters of introduction for his 29-year-old personal secretary, Meriwether Lewis, to the most distinguished American scientists of the day, he played up that second goal - to not only explore but also map and chronicle everything of interest, as he put it, along "the only line of easy communication across the continent." And Jefferson's own interest in this type of expedition - a scientific one - should never be discounted. Such a "voyage of discovery" had been a dream of his father, Peter Jefferson, and Thomas had tried to mount such an expedition four times with four different men prior to his Presidency. Jefferson was himself an amateur scientist who must stand with the foremost men of his time. Notes on the State of Virginia, his only book, was one of the first examples of scientific geography, preceding the work of Humboldt by 50 years, and drawing upon Bernhard Varenius' Geographia generalis (1650). By 1803, Jefferson was probably the most informed American on the totality of the geography of the West, and had the largest library anywhere on this subject.

It is obvious that Jefferson played many political games to launch the Lewis and Clark expedition, but we should never discount the incredible scientific work the explorers accomplished. They made the first systematic reports, based on scientific measurement and observations, of the Missouri River - not only its course, but its flora and fauna, depth and current, tributaries and inhabitants. By my count they described for science 120 mammals, birds, reptiles and fish, as well as at least 182 new plant species. They made the first attempt at a systematic record of the meteorology of the West, and less successfully attempted to determine the latitude and longitude of significant geographical points. Their maps were invaluable, their descriptions of the country's geology important. These facts set them apart from contemporary expeditions, most notably those of Zebulon Pike, which made no new scientific discoveries.

There is a reason that such wonderful, Enlightenment-influenced scientific work was possible on the Voyage of Discovery - and that reason was Meriwether Lewis. If not for Lewis' incredible intelligence, background knowledge of the rudimentary science of his day, powers of observation and his ability to apply this knowledge in the field, the significance of the Lewis and Clark Expedition would be greatly diminished. We can say, without exaggeration, that when the Corps of Discovery set out from the St. Louis area in the spring of 1804, they were no more than a bodyguard for Meriwether Lewis' brain! It is true that William Clark later learned from Lewis to observe and classify, and that several of the men were caught up in the enthusiasm of new discoveries as the journey wore on. But it was Lewis alone of the expedition members who stood closest to being a man of science, both during and after the expedition. If Lewis had fallen to his death from the cliff near modern St. Albans, Missouri on May 23, 1804, the expedition would have been a failure, for one of its two stated goals - scientific exploration - could not have been met.

Where and when did Meriwether Lewis come to possess the knowledge he needed to pull off such a feat? Some of it came from past experience, and some from long association with Thomas Jefferson, one of the great minds of the 18th century. The rest came from crash courses he received just prior to his departure for the West.

On February 27, 1803, President Jefferson confided in a letter to Benjamin Smith Barton, a physician and naturalist at the University of Pennsylvania, why he chose Lewis to head the expedition, saying that It was impossible to find a character who to a compleat science in botany, natural history, mineralogy & astronomy, joined the firmness of constitution & character, prudence, habits adopted to the woods, & a familiarity with the Indian manners & character, requisite for this undertaking. . . . Altho' no regular botanist he possesses a remarkable store of accurate observation on all the subjects of the three kingdoms, & will therefore readily single out whatever presents itself new to him in either.

Jefferson ended his letter by asking Barton to train Lewis, and continued: "I make no apology for this trouble, because I know that the same wish to promote science which has induced me to bring forward this proposition, will induce you to aid in promoting it." Jefferson wrote similar letters to the other prominent American scientists of the day: Andrew Ellicott, Robert Patterson, Caspar Wistar and Dr. Benjamin Rush. The deaths of Benjamin Franklin and David Rittenhouse in the 1790s left these five men, along with Jefferson, as the leaders of the American Philosophical Society in Philadelphia, the primary scientific society in America at that time.

With only the precedent of the voyages of Britain's Captain James Cook, Lewis was instructed to compile scientific data on every aspect of the terrain through which he would pass. On April 19, 1803 Meriwether Lewis arrived in Lancaster, Pennsylvania to learn to plot latitude and longitude from astronomer Andrew Ellicott. Ellicott, a former Surveyor-General of the United States, had been corresponding with Jefferson for some time about the projected expedition to the Pacific, making recommendations about what surveying equipment should be taken. He trained Lewis, regulated the expedition's chronometer and oversaw the construction of a sextant and portable horizon. He also developed a new type of artificial horizon for the sextant especially for Lewis.

Lewis next traveled to Philadelphia for further instruction in medicine and the natural sciences, including comparative anatomy. Lewis met with Dr. Benjamin Rush to learn about medicine. Dr. Rush was the most eminent American physician of his day. A leading patriot during the Revolution, Rush was a signer of the Declaration of Independence. Rush not only gave Lewis a crash course in medicine, but also instructed him about American Indian history. Rush was apparently impressed with Lewis; he wrote Jefferson that "Mr. Lewis appears eminently qualified for it [his mission]." It is not known why a physician was not taken on the expedition. It might have been due to Jefferson's prejudice against doctors, or perhaps because he felt Lewis qualified, with instruction, to perform the necessary tasks. Lewis' mother, Lucy Marks, was a well-known herb doctor in Virginia, and she had taught her son much about her trade.

Lewis next went to study with Dr. Benjamin Smith Barton, who also lived in Philadelphia. Barton, a professor of botany at the University of Pennsylvania, instructed Lewis in botany and zoology. Barton was the first professor of natural sciences in the United States and wrote the first U.S. textbook on botany. Dr. Barton was not in good health in 1803, although he suggested to Lewis that he might be interested in going along with him at least as far as the Illinois country. After the expedition Barton volunteered to edit the scientific portions of the journals for publication, but died before he could do so. It is not known whether it was Barton or Jefferson who taught Lewis how to prepare and label plant and animal specimens; either was capable of doing so. Lewis took 10 or 12 natural science reference books with him all the way to the Pacific Ocean and back, including Barton's botany textbook.

Dr. Caspar Wistar rounded out Lewis' instruction in the natural sciences. A native of Philadelphia, and like Rush and Barton schooled in Edinburgh, Scotland, Wistar returned to the United States to become one of its most eminent scientists. After teaching chemistry and physiology at the College of Pennsylvania for many years, he was given the chair of anatomy at the University of Pennsylvania's medical school. His lectures were so interesting that students reportedly flocked to see them whether they were pre-med or not. Wistar published the first U.S. book on anatomy, and was honored by the English-born botanist Thomas Nuttall, who named the vine "Wisteria" after him. Wistar was a specialist at "comparative anatomy," and talked with Lewis about living animals, fossil animals, and the possibilities of megalonyx (Jefferson's ground sloth, discovered as a fossil) or mammoths still living to the west of the Mississippi. Wistar drew up a list of questions for Lewis to answer as he passed through the West involving the natural history of each region. Unfortunately, this original list has never been found.

In addition to all of these activities, Lewis most certainly visited the famous museum of Charles Willson Peale, then located on the second floor of Independence Hall. The museum included paintings of the bird and animal species of North America. Many fine specimens of everything from preserved bird species, toads and snakes, to a full fossil skeleton of a mammoth were on display, not to mention a unique collection of Indian artifacts from far and wide. Lewis could absorb much useful information in this museum.

Lewis left Philadelphia on June 1 and traveled to Washington, D.C. to meet with President Jefferson and make final arrangements for his journey to the Pacific. These included writing a long letter on June 19 to an old friend, William Clark, asking him to recruit men in his area for the expedition and whether or not he would like to join as co-leader.

Lewis left Washington on July 5, 1803, for Harpers Ferry, where he picked up the over 3,500 pounds of supplies and equipment he had amassed to take overland to the Pittsburgh area. At Elizabeth, Pennsylvania, Lewis was held up for over a month waiting for his 55-foot keelboat to be built. On August 31 the keelboat was finally completed and Meriwether Lewis began his journey down the Ohio. The water on the Ohio River was low, causing long portages at various points and delays that must have been vexing to Lewis.

Lewis began to record scientific observations immediately, and long before venturing into uncharted country the work of science and the investigation of the physical world was started. Lewis reached Cincinnati, Ohio on September 28, 1803, where he talked with Dr. William Goforth, a local physician who was excavating the fossil remains of a mastodon at the Big Bone Lick in Kentucky. Lewis traveled to Big Bone Lick himself, spending five days there and sending a box of specimens back to President Jefferson, along with an extremely detailed letter describing the finds of Goforth. The letter weighed the pros and cons of whether the tusks found by Goforth belonged to a mammoth or to another animal. The letter demonstrated how well Lewis had learned the scant knowledge of the period regarding fossil remains, and reveals a personal interest in the subject.

On October 14, 1803, the keelboat arrived in Clarksville, Indiana, where Lewis joined William Clark, his slave York, and the so-called "nine young men from Kentucky" who formed the backbone of the expedition's crew. The expedition got under way once more on October 27, moving down the Ohio to Fort Massac, Illinois, by November 11. Today this is a wonderful replica of the American fort as it looked when Lewis and Clark visited in 1803. Lewis hired interpreter George Droulliard and gained volunteers from the U.S. military at the fort, then moved on to the vicinity of modern Cairo, Illinois. Here Lewis and Clark worked on their first joint scientific research and description; to study the geography of the confluence of the Mississippi and Ohio rivers. Lewis and Clark measured and compared the speed of the currents and the volume of the rivers, mapping the region and noting its geology. They ended their surveys at Cairo on November 19, and proceeded up the Mississippi River, now working against the current. On the 25th Lewis and Clark stopped to describe and climb Tower Rock below Kaskaskia, Illinois, noting the type of rock it was composed of, its height, and drawing maps showing its location.

During the winter in the St. Louis area, Lewis and Clark were busy with training their crew, obtaining supplies and finding out all they could about the territory ahead. But the work of scientific inquiry continued, even in the heart of St. Louis, as Lewis sat in the garden of Pierre Chouteau on March 26, 1804. In the stone-walled enclosure, Chouteau had a specimen of the Osage Orange tree growing. The tree's natural range then extended only to about 300 miles to the West of St. Louis. Chouteau allowed Lewis to take cuttings to send back to Jefferson. This is a good example of Lewis' restless and far-ranging mind - even in the midst of a domestic garden, he noticed an unusual tree and described it for science. This was chronologically the very first of the over 300 plants and animals described by Lewis and Clark over the subsequent 2½ years.

As the Expedition left St. Louis, Lewis sent back a description of the Osage orange along with specimens of local minerals (salt, silver and lead), the fossils from Big Bone Lick, the contents of a buffalo's stomach and a specimen of the Plains horned toad collected by Charles Gratiot in western Missouri. Prior to leaving St. Louis, the scientific Lewis and Clark Expedition had already begun. As the expedition began to move up the Missouri, it is interesting to note that Lewis focussed on the details - the animals, the type of rocks, the trees and grasses - along the route. How fast was the current? How high were the cliffs? Was that bird different from one known in the East? On the other hand, it was the sergeants and privates, in their journals, who chronicled some of the beauties of the river, its moods, and the caving in of its banks, giving us an overall impression of what the voyage up the river was like in 1804.

Lewis went on to describe some of the animals of the voyage, making notes and polishing his observation skills on the plains gray wolf and eastern wood rat - the first animal new to science encountered on the voyage - In what is today Osage County, Missouri. By this time the tone had been set and the tasks defined for this incredible scientific mission. For, more than a mere stunt to see if the continent could be crossed and conquered, more than a diplomatic mission to Indian peoples, more than an instance of "manifest destiny," the Lewis and Clark Expedition was a scientific foray. Like Diderot with his Encyclopedia, Jefferson charged Lewis with chronicling "the animals of the country generally, & especially those not known in the U.S. the remains and accounts of any which may [be] deemed rare or extinct . . . [observe] the face of the country, it's growth and vegetable productions; especially those not of the U.S. . . ." He was told to make these observations "with great pains & accuracy, to be entered distinctly & intelligibly for others as well as yourself." It is this aspect of the expedition, fulfilled in every sense of its injunction, which sets the Lewis and Clark Expedition apart and plays a major role in its resonance 200 years later.