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_ had already entered the mouth of the river. But Lewis and Clark were the first white men to reach it overland. [Sidenote: Amendment as to the election of President.] [Sidenote: The Twelfth Amendment, 1804.] 245. The Twelfth Amendment, 1804.--Four presidential elections had now been held under the method provided by the Constitution. And that method had not worked well (pp. 171, 176). It was now (1804) changed by the adoption of the Twelfth Amendment which is still in force. The old machinery of presidential electors was kept. But it was provided that in the future each elector should vote for President and for Vice-President on separate and distinct ballots. The voters had no more part in the election under the new system than they had had under the old system. The old method of apportioning electors among the states was also kept. This gives to each state as many electors as it has Senators and Representatives in Congress. No matter how small its territory, or how small its population, a state has at least two Senators and one Representative, and, therefore, three electors. The result is that each voter in a small state has more influence in choosing the President than each voter in a large state. Indeed, several Presidents have been elected by minorities of the voters of the country as a whole. [Sidenote: Jefferson reëlected, 1804.] [Sidenote: Strength of the Republicans.] 246. Reëlection of Jefferson, 1804.--Jefferson's first administration had been most successful. The Republicans had repealed many unpopular laws. By the purchase of Louisiana the area of the United States had been doubled and an end put to the dispute as to the navigation of the Mississippi. The expenses of the national government had been cut down, and a portion of the national debt had been paid. The people were prosperous and happy. Under these circumstances Jefferson was triumphantly reëlected. He received one hundred and sixty-two electoral votes to only fourteen for his Federalist rival. [Illustration: STEPHEN DECATUR.]