While Jefferson spent early 1803 crafting his instructions for the expedition and teaching Lewis the art of the sextant and other measuring instruments, Lewis formulated the shape and size of the expedition. His focus fell in two areas—people and supplies.

The matter of people was ever-changing. Lewis first envisioned a corps of about a dozen men. By the time the permanent Corps of Discovery was finalized a year and a half later, that estimate had more than tripled. The traveling party swelled and shrank depending on where the journey was and what local guides and hired hands Lewis brought on along the way.

The issue of supplies offered a far more difficult challenge. Lewis needed to feed and clothe his men. He needed weapons and ammunition. He needed boats. He needed items to trade with the Indians. He needed medicine. Determining what and how much was an overwhelming task.

Lewis left Washington March 14, 1803, for Philadelphia, where he would get his crash course in science. Lewis' education was only part of the trip. On this journey he would begin to supply the expedition.

Lewis' first stop was Harper's Ferry, VA. There he purchased weapons and ammunition. He also had work begun on an iron frame boat that he and Jefferson had conceived for use past the Great Falls of the Missouri.

The very first stop Lewis made in the name of the upcoming expedition was Harper's Ferry, VA. At the armory there he directed construction of his iron frame boat and also arranged for supplies and weapons. Image © 2002 www.clipart.com.

In mid-April Lewis left Harper's Ferry for Philadelphia. After a stop for some celestial observation training in Lancaster, PA, where he bought more rifles, he arrived in Philadelphia in early May. He also traveled via the nation's first long distance, hard-surfaced toll road.

Lewis called on two primary sources in Philadelphia, Israel Whelan , who had been appointed purveyor of public supplies for the federal government in the city, and the recently built Schuylkill Arsenal. Whelan rounded up a variety of goods, from dried soup and pencils to Indian presents such as beads and knives. For military basics such as tents and clothing, Lewis relied on the arsenal. The boats would come later once Lewis began the expedition.

< previous | next >