reat Britain were at peace. But it
soon looked as if war would begin again. Napoleon knew that the British
would at once seize Louisiana and he could not keep it anyway. So one
day, when the Americans and the French were talking about the purchase
of New Orleans, the French minister suddenly asked if the United States
would not like to buy the whole of Louisiana. Monroe and Livingston, the
American ministers, had no authority to buy Louisiana. But the purchase
of the whole colony would be a great benefit to the United States. So
they quickly agreed to pay fifteen million dollars for the whole of
Louisiana.

[Sidenote: Louisiana purchased, 1803. _Higginson_, 244-245; _Eggleston_,
234; _Source-Book_, 200-202.]

[Sidenote: Importance of the purchase.]

243. The Treaty Ratified.--Jefferson found himself in a strange
position. The Constitution nowhere delegated to the United States power
to acquire territory (p. 164). But after thinking it over Jefferson felt
sure that the people would approve of the purchase. The treaty was
ratified. The money was paid. This purchase turned out to be a most
fortunate thing. It gave to the United States the whole western valley
of the Mississippi. It also gave to Americans the opportunity to
explore and settle Oregon, which lay beyond the limits of Louisiana.

[Illustration: THE UNITED STATES IN 1803.]

[Sidenote: Lewis and Clark, 1804-6. _Higginson_, 245-247; _McMaster_,
219-221;_Source-Book_, 206-209.]

[Sidenote: The mouth of the Oregon.]

244. Lewis and Clark's Explorations.--Jefferson soon sent out
several expeditions to explore the unknown portions of the continent.
The most important of these was the expedition led by two army officers,
Meriwether Lewis and William Clark, brother of General George Rogers
Clark (p. 116). Leaving St. Louis they slowly ascended the muddy
Missouri. They passed the site of the present city of Omaha. They passed
the Council Bluffs. The current of the river now became so rapid that
the explorers left their boats and traveled along the river's bank. They
gained the sources of the Missouri, and came to a westward-flowing
river. On, on they followed it until they came to the river's mouth. A
fog hung low over the water. Suddenly it lifted. There before the
explorers' eyes the river "in waves like small mountains rolled out in
the ocean." They had traced the Columbia River from its upper course to
the Pacific. Captain Gray in the Boston ship _Columbia_ h