He had worked closely with Jefferson for a long time, and knew a lot about the wilderness and other things from reading Jefferson's many books and from Jefferson himself.
At the time, only Jefferson and Lewis lived in the White House so things were pretty quiet most of the time. The quiet ended, though, in the summer of 1802. Alexander Mackensie had explored Western Canada and had reached the Pacific just north of Vancouver. He wrote a book based on his exploration urging Britain to set up more forts and trading posts in the west. This worried Jefferson, and he realized that Americans had to act right away. He and Lewis began planning an expedition that was to start the following year. They also decided that not only would it be just an exploration of unknown territory, but also a scientific expedition.
Now Jefferson needed to get Congress's approval of the expedition so on January 18, 1803, Jefferson sent a confidential message to Congress. He felt that the United States needed to strengthen through commerce. He also felt that they needed to strengthen the relations they had with the Indians that lived in the United States who, according to Jefferson, were "growing more and more uneasy at the constant diminution of the territory they occupy". He included all of this in his message, and at the end he requested that Congress provide a sum of $2500 "for the purpose of extending the external commerce of the United States-.
"The appropriation of two thousand five hundred dollars, for the purpose of extending the external commerce of the United States, while understood and considered by the Executive as giving the Legislative sanction, would cover the undertaking from notice, and prevent the obstructions which interested individuals might otherwise previously prepare in its way."".
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The expedition would actually end up costing much more than the money Jefferson requested "about $38,000 in total "but the sum provided was enough to fulfill Jefferson's desire to send the expedition.
