National attention was focused in 2003 as the 200th anniversary of the beginning of the Lewis and Clark expedition. Most consider that the expedition actually began in 1804 from the Illinois shore of the Mississippi River just north of St. Louis, Missouri, but the Eastern Legacy was also extremely significant as Merewether Lewis not only had to organize the expedition, recruit most of the men and have the boats constructed and move westward down the Ohio River, he also had to get to know William Clark and share with him what he had learned from his crash courses in biology, medicine, and astronomy and learn surveying from Clark as well. Although there has been very little in-depth research and/or published materials on the significance of southernmost Illinois to the Lewis and Clark Expedition, the lower Ohio River at its confluence with the Mississippi became their training base. Several of the most important members of the expedition were recruited at Fort Massac and Fort Kaskaskia and the first attempts at celestial observation and map making were conducted at the Confluence, the present site of Cairo, Illinois in November of 1803. In addition, there appears to be an intriguing connection, albeit negative, related to General Wilkinson and Aaron Burr and Cantonment WilkinsonVille with Lewis & Clark. Several of the members of the expedition recruited at Fort Massac and Kaskaskia had previously served at Cantonment WilkinsonVille.i

Mapping at the Confluence

In 1796, seven years before Lewis and Clark began their expedition, Andrew Ellicott, surveyor general for the U. S. Government, prepared the first government maps of the Ohio and Mississippi Rivers. Ellicott conducted celestial observations and determined the longitude and latitude of the confluence of the two largest rivers in North America. In 1803, just before President Jefferson completed the purchase of the Louisiana Territory, the Mississippi River was still the western edge of the United States as all lands west and north of the Mississippi belonged to Spain, France, or England. With the Louisiana Purchase, the Confluence of these two great rivers became the center of the new United States and the new territory belonging to the United States was generally undiscovered and undocumented. With the coordinates of the Confluence established by Ellicott, this important junction of the rivers would then become the first significant place where Lewis and Clark could teach each other their respective skills.

At the completion of their journey east down the Ohio River in late November 1803, Lewis, Clark, and their men (and Black Labrador dog, Seaman), after recruiting George Druillard from For Massac, camped at the Confluence of the Ohio and Mississippi Rivers for 5 days and 6 nights accomplishing one of the most significant activities in their preparations for the expedition. William Clark was a already a skilled surveyor and Meriwether Lewis had been sent from Philadelphia to Lancaster, PA by President Jefferson to study with Andrew Ellicott, surveyor, astronomer and mathematician to learn celestial navigation skills using a sextantii, octant, circumferentoriii, artificial horizoniv, measuring chain, the chronometerv, and other instruments.

This was William Clark’s second known encounter with the Confluence of the rivers region for in 1795, he had been sent by General Anthony on a mission to New Madrid on the Mississippi to communicate with Spanish authorities.vi This account indicates that Clark wrote in a report of his experience going back upstream that as I ascended the Mississippi I found its current Rappid and dificult and Country on each side low, with no. of Islands. From twelve to fifteen miles pr. day was as much as I could conveniently make with the exertion of a good crew.vii Lewis apparently hadn’t previously experienced this and, although there only minor mention of this in the Journals, author Stephen Ambrose writes that when on November 20, 1803 after Lewis and Clark had completed their work at the Confluence, the expedition headed out into the Mississippi, then turned upstream. Lewis and Clark scholar Arlen Large speculates that this may have been the instant when the captains decided they needed more men. The power of the river with its boils and swirls and floating obstacles, awed them.. . . . . Lewis now was face to face with what would be his major problem almost until he reached the Continental Divide, moving relatively large craft upstream on a major river.viii The Confluence was the turning point in the expedition when it became obvious that it was all up-river from the Confluence and it was the starting point for the mapping and notation techniques used to document the rest of the journey.

At the Confluence, according to the Moulton journals, “the captains made their first efforts to determine latitude and longitude”.ix Instruments required to accomplish this are the sextant, an octant (during the summer when the sun is higher in the sky, and a chronometer.x Their brass sextant of 10” radius consists of an arm the moves along an arc calibrated with a scale of degrees, minutes, and seconds and has several interchangeable eyepieces, a mirror, a horizon glass, and adjustable shades for viewing the sun. “It is typically used to measure the angular distance of the sun from the horizon and to measure the angular distances between the moon, and sun, or a star.xi The sextant was traditionally used for navigation at sea where the horizon is obvious, but on land, the horizon is often obscured by trees, hills, and/or mountains. To solve this problem, inventer and instrument maker Robert Patterson of Philadelphia constructed an artificial horizon using mirrors and water for reflecting surfaces to substitute for the natural horizon. The Chronometer, purchased by Lewis from watchmaker Thomas Parker, also of Philadelphia, is a basically a clock which must be wound every day at noon which allows one to compare local time with Greenwich mean time.xii

The three or four basic instruments were used in conjunction with astronomical and mathematical reference books to verify locations of heavenly bodies on specified dates with respect to longitude and latitude on the planet. Calculations for latitude were simple, but calculations for longitude were much more difficult, so Lewis and Clark carefully recorded the data for others to calculate and document at a later date.

14” Octant Artificial Horizon

14” Brass Sextant with Storage Box Surveying Instruments & Equipment

Instrument and Equipment Collection – U.S. Custom House Museum, Cairo, IL xiii

Lewis and Clark also had basic surveying instruments, including the surveyor’s compass, called in the journals, a “circumferentor." In conjunction with an observation of the sun with a sextant or octant, a circumferentor was used to determine magnetic declination, the difference between true and magnetic north, which varies according to one’s location.xiv Lewis and Clark took these types of readings throughout their journey carefully notating detailed sketch maps used later by cartographers to develop the finished maps we see today.

First Map of the Expedition – Yale University – Beinecke Rare Books Library Collection

The first sketch survey map of the entire journey was of the Confluence and was competed by Clark as they wintered near St. Louis. The map depicted the basic configuration and dimensions of the two major rivers at their Confluence.xv xvi On the back of the map Clark made additional sketches and a written description explaining the directions and notations on the map itself. A portion of his text is in italics below: (Note: To better understand Clark’s notations, the map below is rotated so that north is up ant to the left and large block letters have been added by the author to correspond to Clarks notations. In addition, certain phrases that correlate with each direction and dimensional notation are underlined)xvii

Lewis and Clark sketch map at the Confluence with notations by the author

(CLICK HERE FOR HIGH RESOLUTION IMAGE OF MAP)

From the Point A of the Mississippi & Ohio 25 poles from the highest Land B on the Sand point – From thence e A to A Signal on the opposite Side of the Ohio C is N. 10 ½ degrees E 149 poles and 32 ol: and 7/10 to the bank D – From the Said beginning A up the Ohio N 52 1/2degrees W 115 po: to a -- E --- Thence to the aforesaid Signal C on the opposite Side of the Ohio is N, 68 degrees, E-

From the Said Beginning A Cross the Mississippi to a Signal F is S 33 degrees E – (235 poles) From Said point A up the Mississippi is S 74 degrees W 117 po: G (to a Bluff of Sand opposite the Lower point of an Island) From thence to the Said Signal F is s 56 degrees E – (To the upper point of Island is S 53 W, to Lower point is S 15 E) From the Said point or begn: to the point of the West Side of the Mississippi is S 75 degrees E – From Said Point A to a forked Tree on the East Side of the Mississippi standing on the banke H is S 77 degrees E 700 poles (form thence to the high Land about 500 poles –

From the Signal C on the East Side of the Ohio to a forked Tree ont eh bank below J is S 66 degrees E – To the Point ofn the W Side of the Miss: H below is S 55 degrees E – To the upper (house) or Signal F is S 16 degrees E Passing the lower point of the Sand Bar making form the Island above

From the highest part of the point B along the high land up the Miss: is S 48 degrees W 4 po: 14 links, S 72 W. 144 poles: S 13 degrees W.8 po to the river where the bank Cave in. N N 85 seconds E 46 poles to the Willows, where the Bank cease to Cave in in the course of the 3d observation

(The Course of the bank on the Spa: [Spanish] Side of the Mississippi: from the upper house Down is nearly S 85 degree E. abt 1 ½ miles, & S 80 E about 450 yards to the lower point – Capt L) [end of entry in Clark’s hand}

Additional Drawing Data:

K- Tree symbol – possibly representing edge of section of wooded area

L- Undetermined symbol – forms suggest survey coordinates, Tent structure or some kind of animal.

M - Deer drawing / symbol

Other Activities

Lewis and Clark conducted other significant activities while at the Confluence. They met with the “Shawnee and Delawars” on the Missouri shore ( or “the Spanish side of the Mississippi”)xviii at which time Lewis refused an offer with “considerable indignation” to trade his dog Seaman for three beaver skins. xix Their men caught and carefully measured and sketched a 128 pound catfish (4’-3 ½” long and 3’-9” circumference around its head) and saw their first Heath Hen.xx They dealt with the first discipline problems with their crew. They visited the abandoned Fort Jefferson located on the Kentucky shore of the Mississippi just a few miles downriver from the Confluence that had been constructed in 1780 by William Clark’s older, and famous, brother, George Rogers Clark.xxi Although these are important activities, the self training involved in successfully completing the difficult scientific task of determining where they were on the planet and developing accurate surveying and mapping techniques to complete their documentation of their trip to the Pacific and back are probably the most significant technical achievements of the expedition.

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