About the same time the United States acquired another considerable extent of territory. The Kaskaskia Indians, occupying the country which extended along the Mississippi, from the mouth of the Illinois to the Ohio, and which is considered the most fertile in the Union, finding themselves so reduced by wars and other causes as to be unable to defend themselves from the neighbouring tribes, transferred their country to the United States, reserving only for agricultural purposes sufficient to sustain the remnant of the nation. For this valuable acquisition the United States engaged to extend to them protection, and give them annual aid in money, implements of agriculture, and other articles of their choice. In 1803 an appropriation was made by congress for defraying the expenses of an exploring party across the continent to the Pacific. This was a scheme which the president had much at heart, and under his auspices it was carried out; Captain Meriwether Lewis being at the head of the expedition, while second in command was Captain Jonathan Clarke, brother of George Rogers Clarke, and under them twenty-eight well-selected individuals, with an escort of Mandan Indians. The expedition set out on May 14th, 1804. Since 1801 war had existed between the United States and Tripoli. Without going into minute details of this war, we will follow the abstract given of it by Willson. “In 1803 Commodore Preble was sent into the Mediterranean, and after humbling the emperor of Morocco, he appeared before Tripoli with most of his squadron. The frigate Philadelphia, under Captain Bainbridge, being sent into the harbour to reconnoitre, struck upon a rock, and was obliged to surrender to the Tripolitans. The officers were considered prisoners of war, but the crew were treated as slaves. This capture caused great exultation to the enemy; but the daring exploit of Lieutenant, afterwards Commodore Decatur, humbled the pride which they felt in this accession to their navy. Early in February of the following year, Lieutenant Decatur, under the cover of evening, entered the harbour of Tripoli, in a small schooner, having on board but seventy-six men, with the design of destroying the Philadelphia, which was then moored near the castle, with a strong Tripolitan crew. By the aid of his pilot, who understood the Tripolitan language, Decatur succeeded in bringing his vessel in contact with the Philadelphia, when he and his followers leapt on board, and in a few minutes killed twenty of the Tripolitans and drove the rest into the sea.