How to Use the Images

Table of
Contents

Illustration 1: Portion of Lewis and Clark expedition map from the Mississippi to the Pacific Ocean, 1814.

Illustration 1 was copied and reduced from William Clark's large manuscript map of the West by Samuel Lewis, a Philadelphia mapmaker, and engraved by Samuel Harrison. This map accompanied the first official account of the expedition, History of the Expedition under the Command of Captains Lewis and Clark, 1814. Clark's map was the first to chart the northwest part of North America. The map was derived from daily observations while in the field and Indian reports and maps copied by Lewis and Clark. Clark was the primary cartographer on the trip. His lists of expedition equipment indicated that they carried quite a few surveying instruments. Most all of them were far more useful for short rather than long-distance measuring. These included a "two pole chain" (33 feet long), a "log line reel" which measured the rate of boat travel (these measurements were affected by river currents), compasses, quadrants, sextants, and a chronometer. To view a full version, please visit the illustration on the Library of Congress website.

Illustration 2: Westward Crossing, Lewis and Clark Expedition, 1958.

Illustrations 1 and 2 are roughly the same general area.

Questions for Illustrations 1 & 2

1. Look up the definitions for any of the cartography equipment used by Lewis and Clark that you are not familiar with. Considering the crude instruments used and the conditions under which the map was drawn, how would you describe Illustration 1? What types of features did Clark make note of on his map?

2. See how many Indian tribal names you can read and highlight them on Illustration 1. Although difficult to read, noted in italics under the tribal names is the number of "souls" (ie. under the Black Foot Indians, it notes that there are 3500 souls). What is meant by "souls"? Why might this information be useful to future travelers using this map?

3. On Illustration 2, use the scale provided to calculate the approximate distance of this portion of their journey. How much of the distance did they cover by water? How much of the travel was over land?

4. On Illustration 2, locate the sites mentioned in Reading 2. Does this map give you a better idea as to what the terrain was like during this portion of the journey? Why or why not?

5. Using the information provided in the caption, your answers to Questions 1-4, and the illustrations to determine what information is provided in Illustration 1 that was not provided in Illustration 2 and vice versa. Think about when each map was made and who its audience was, what might account for the differences in the details?

¹Roy E. Appleman, ed., Advance of the Frontier 1763-1830: Lewis and Clark (Washington, D.C.: United States Department of the Interior National Park Service, 1958).

* The images on this screen have a resolution of 72 dots per inch (dpi), and therefore will print poorly. You can obtain a larger version of Illustration 1 & Illustration 2, but be aware that each file will take as much as 55 seconds to load with a 28.8K modem.