The Lewis and Clark Expedition: Seventh-Graders' Perspectives on Mapping (Written by a team of Will James Middle School Seventh-Graders, with Assistance from the BLM-Montana/Dakotas Office) Hello! We are a seventh-grade team of geography students at Will James Middle School in Billings, Montana. We set out to investigate the mapping tools and methods of the Lewis and Clark Expedition and compare these with present-day mapmaking. We learned a lot about 1803 "state-of-the-art" navigation and how imagination and intuition carved a part of our Montana history. We hope you will enjoy reading about our discoveries.
Imagine going on an expedition with two leaders, Meriwether Lewis and William Clark. Our mission is to map a vast, unknown land with tools that are state-of-the-art, using instruments such as a sextant, octant, compass, and a log line. This exploring mission will encompass all of the land west of the Mississippi to the mouth of the Columbia River at the Pacific Ocean, and will take approximately four years to complete. Imagination drives exploration, which is exactly what initiated the Lewis & Clark Expedition. President Thomas Jefferson expressed just such imaginative interest in his letter of instruction to Meriwether Lewis on June 20, 1803: "The interesting points of the portage between the heads of the Missouri, and of the water offering the best communication with the Pacific Ocean, should be fixed by observation, and the course of that water to the ocean. Your observations are to be taken with great pains and accuracy for others to comprehend . . ." The Expedition created about 100 maps to share their knowledge of the land. It was a great feat to map this immense country, using the tools they had available. Captains Clark and Lewis took along approximately twenty technical "mathematical instruments," plus two books, Kelly's Spherics and the Nautical Almanac, as well as several astronomical tables. The cost of the supplies totaled $473.45, and included: a Spirit level, a Case plotting instrument, a two-pole chain, plated and brass pocket compasses, a brass boat compass, a magnet, a Hadleys quadrant, a sextant, talc, a surveying compass, a circular protractor and index, a pocket telescope, a nautical ephemeris, a requisite tables, Kirwan's Mineralogy, a chronometer and keys ( which cost $250, the most expensive of the equipment), a log line reel and a log ship.
The octant (Hadley's quadrant) and the sextant were used to find latitude. To obtain the latitude readings, Lewis and Clark took around twelve sightings of the sun right before and after solar noon in order to measure the sun's height above the horizon. Pairs of sightings at equal altitudes, before and after noon, were used to compute the exact time the sun reached its highest point. The chronometer or timekeeper were used for longitude. Longitude readings were taken, but left to be calculated later when they returned to St. Louis. The two-pole chain gave an accurate measurement of 33 feet, and a measuring tape (rare back then) was also used. The log line reel and log ship were used to measure the rate and distance of boat travel. Plotting instruments and the circular protractor were used to draw their maps. From the many books and journals written about the expedition, we read information about the mapping methods Lewis and Clark used. Gary Moulton in his Atlas of the Lewis and Clark Expedition, wrote, "For courses and distances, Clark relied mainly on his compass readings, and occasionally he trusted dead reckoning . . . He probably employed the route traverse method, taking bearings at each turn of the trail or bend in the river and plotting those shifts on his maps . . . After traveling forward some miles Clark would turn and take an azimuth reading from his previous point of sighting. This procedure was necessary because he could not always determine his next point of observation." This information was pretty complex for us to understand, so to try and gain a better sense of the traversing method, we built some instruments for determining angles and taking back sightings. We took these instruments outside and worked in teams to navigate the westbound and eastbound routes of the Expedition through Montana, simulating the traversing method in the process.
The Expedition's instruments were all subject to error. However, they also sought geographic information from the guide Sacajawea and from the Indian tribes they met along the journey. Geographic information was given to them both verbally and in various map form, such as drawing on animal hides, or creating a "relief map" using rocks and dirt on the ground. Clark often drew maps using standard symbols such as:
Lewis and Clark would be amazed to see the mapping tools used today. GPS (Global Positioning System) receivers allow anyone to get exact latitude/longitude coordinates, accurate time, and altitude within seconds.
GPS is only one tool used in mapping today. GIS (Geographic Information Systems) is a system of hardware, software, and digital data that can be used to lay out routes (like the Expedition), study changes in the environment to determine the best location for such things as a new school building like our Will James Middle School. The Bureau of Land Management in Billings provided us with various information which we downloaded to help us produce this GIS map of the Lewis and Clark campsites in Montana.
We did this in a matter of minutes; Lewis and Clark had to spend years creating their maps with pen and ink. It's pretty amazing how far technology has come since the early 1800's. Actually it's pretty amazing how far it has come since 1970. We have incredible tools at our fingertips. Lewis and Clark applied their "state-of-the-art" tools with skill and determination. They worked as a team and approached their task with imagination. Skill, determination, teamwork, and imagination were the real "tools" of the Expedition; and these will continue to be the tools that guide mapping into the future. We hope you enjoyed reading about our study of mapmaking. We learned a lot!
The article above is a summary of the findings of the mapping project of one team of seventh-graders from Will James Middle School, Billings Montana. BLM-Montana/Dakotas offered assistance from its ongoing Lewis and Clark project, as well as the GIS and GPS technology of its Geographic Information Systems staff. The seventh-grade writers/editors were Danny, Chad, Jeff, Peter, Sarah, BreAnna, Grady, Norma, Nicole, Riley, and Kasey. Student artists were Chantel and Tai.
Geography Standards involved in this project: National Standards for the Social Studies: Montana State Standards for the Social Studies: For more information on this student project, please contact Lorrene Schardt at BLM-Montana/Dakotas, 5001 Southgate Drive, Billings, Montana 59101, telephone (406) 896-5230, e-mail Lorrene_Schardt@blm.gov. For more information on Lewis & Clark, their mapping techniques, and the upcoming bicentennial of the journey of their Corps of Discovery, please visit the following websites:
Last Updated: July 15, 2003 For questions about our programs contact Bibi Booth
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