The Western boundary of Louisiana, after getting a certain distance from the sea, being the high lands inclosing all the waters running into the Missisipi or Missouri, I think it probable Congress will enable me to send two or more parties the next summer to ascertain some of the most important points in that contour. one will probably ascend the Red river from it’s mouth to it’s source, pass on to the Arcansa at it’s head & descend that to it’s mouth, ascertaining with astronomical precision the longitude & latitude of each source, and laying down the rivers themselves in the same way you did the Missisipi. another party should in the same way delineate two of the most important of the Southern branches of the Missouri. according to Arrowsmith these should be the Padoucas & Panis rivers. but it is difficult with our present information to say which they should be. Capt Lewis will give us the Missouri: and when we settle the source of the Missisipi with the British, I think to have that river surveied down to the mouth of Ohio. for the two first mentioned enterprises I shall want two proper characters. astronomy enough to take the latitude & longitude, the latter by lunar observations, is indispensible, this being the main object of the enterprize. bravery, prudence, habits of hardy living, some knolege of Indian character, a degree of knolege of the subjects of botany, Nat. history & mineralogy, would be useful qualifications, & the more of them the person possessed the better. do you know any persons qualified to take charge of such enterprises? what would be the fitness of mr Gillespie who was with you formerly, for such a matter? I pray you to designate to me as many of the persons within your acquaintance as have the essential talent, and to particularise which of the subordinate qualifications they also possess. what do you think of the methods I suggested in my letter to you of Feb. 26. of last year, for taking lunar observations without a time piece? I have not been able to convince myself of their inadequacy. Accept my salutations & respects.