[Footnote 1: In a description of it which Jefferson sent to Congress in 1804, he actually stated that "there exists about one thousand miles up the Missouri, and not far from that river, a salt mountain. This mountain is said to be one hundred and eighty miles long and forty-five in width, composed of solid rock salt, without any trees or even shrubs on it."] %246. Explorations of Lewis and Clark.%--That this great region ought to be explored had been a favorite idea of Jefferson for twenty years past, and he had tried to persuade learned men and learned societies to organize an expedition to cross the continent. Failing in this, he turned to Congress, which in 1803 (before the purchase of Louisiana) voted a sum of money for sending an exploring party from the mouth of the Missouri to the Pacific. The party was in charge of Meriwether Lewis and William Clark. Early in May, 1804, they left St. Louis, then a frontier town of log cabins, and worked their way up the Missouri River to a spot not far from the present city of Bismarck, North Dakota, where they passed the winter with the Indians. Resuming their journey in the spring of 1805, they followed the Missouri to its source in the mountains, after crossing which they came to the Clear Water River; and down this they went to the Columbia, which carried them to a spot where, late in November, 1805, they "saw the waves like small mountains rolling out in the sea." They were on the shores of the Pacific Ocean. After spending the winter at the mouth of the Columbia, the party made its way back to St. Louis in 1806. %247. The Oregon Country.%--Lewis and Clark were not the first of our countrymen to see the Columbia River. In 1792 a Boston ship captain named Gray was trading with the Pacific coast Indians. He was collecting furs to take to China and exchange for tea to be carried to Boston, and while so engaged he discovered the mouth of a great river, which he entered, and named the Columbia in honor of his ship. By right of this discovery by Gray the United States was entitled to all the country drained by the Columbia River. By the exploration of this country by Lewis and Clark our title was made stronger still, and it was finally perfected a few years later when the trappers and settlers went over the Rocky Mountains and occupied the Oregon country.[1] [Footnote 1: Barrows's _Oregon_; McMaster's _History_, Vol. II., pp. 633-635.] [Illustration: Mouth of the Columbia River]