We feel it a duty incumbent upon us, to acknowledge our obligations to many distinguished individuals, both {3} military and scientific, and particularly to several members of the Philosophical Society at Philadelphia, for their prompt offers of any aid in their power to contribute towards advancing the objects of the expedition at its commencement. We are indebted more especially to Professors James, Walsh, and Patterson, to Dr. Dewees and Mr. Duponceau; each of whom furnished a number of queries, and a list of objects, by which to direct our observations. These we found eminently useful, and we regret to state that, with many of our manuscripts they were inadvertently mislaid, otherwise, they should have been published in this place, for the information of future travellers. An interesting communication from Messrs. Gordon and Wells, of Smithland, Kentucky, was received after the first volume had gone to press, consequently too late for insertion. As a farther introduction to our narrative, we subjoin an extract from the orders of the Honourable Secretary of War to Major Long, exhibiting an outline of the plan and objects of the Expedition. "You will assume the command of the Expedition to explore the country between the Mississippi and the Rocky Mountains." "You will first explore the Missouri and its principal branches, and then, in succession, Red river, Arkansa and Mississippi, above the mouth of the Missouri." "The object of the Expedition, is to acquire as thorough and accurate knowledge as may be practicable, of a portion of our country, which is daily becoming {4} more interesting, but which is as yet imperfectly known. With this view, you will permit nothing worthy of notice, to escape your attention. You will ascertain the latitude and longitude of remarkable points with all possible precision. You will if practicable, ascertain some point in the 49th parallel of latitude, which separates our possessions from those of Great Britain. A knowledge of the extent of our limits will tend to prevent collision between our traders and theirs." "You will enter in your journal, every thing interesting in relation to soil, face of the country, water courses and productions, whether animal, vegetable, or mineral." "You will conciliate the Indians by kindness and presents, and will ascertain, as far as practicable, the number and character of the various tribes, with the extent of country claimed by each." "Great confidence is reposed in the acquirements and zeal of the citizens who will accompany the Expedition for scientific purposes, and a confident hope is entertained, that their duties will be performed in such a manner, as to add both to their own reputation and that of our country." "The Instructions of Mr. Jefferson to Capt. Lewis, which are printed in his travels, will afford you many valuable suggestions, of which as far as applicable, you will avail yourself."