In my last letter I informed you that I expected Congress would authorise me to take measures for exploring the principal Western waters of the Missisipi & Missouri. this measure was however neglected till near the close of the session, and then very inadequately provided for in a bill on it’s passage, from a want of previous enquiry & consideration of the sum necessary. 3000. D. only were appropriated to that purpose. as this is a very scanty provision, even for a single party, I have concluded to apply it to the most interesting part of the country, the Arkansa & Red rivers. this is exactly the portion, relative to which, from your vicinity to it comparatively with ours, I proposed to ask your aid and superintendance. altho’ time has not permitted me to await your permission, yet, presuming on your attachment to science, & attainments in it, and the dispositions to aid it necessarily flowing from these, I have made out the instructions now inclosed, for the person who is to direct the mission, on the ground of your consent to become our co-operator. a blank is left at the head of the instructions for the name of the person, to be filled up by yourself. I had suggested the names of mr Walker of Natchez, & mr Gillespie of N.C. as persons who had been proposed to me as competent to our object. but as both of them are personally known to you, I have thought it best to leave to you to select either, or to reject both, if you are able to insert the name of any one preferable to them. to these will be added by the Secretary at war the general provisions for the execution of this enterprize, referred to in the 2d. paragraph of my instructions, and to both I shall ask the favor of you to add supplementorily, whatever you may deem advantageous, and whatever may be necessary to expedite the mission with the least delay possible, taking such measures, and giving such directions to all persons concerned, as the state of things on the spot may call for, so as to supply in every case the necessity of recurrence to us. such a recurrence would, from our distance, defeat the object for one year, a portion of time we wish not to lose.

You will percieve by the instructions that a Doctr. George Hunter of Philadelphia is appointed to go as a coadjutor & successor in case of accident to the principal. his fort is chemistry. in the practical part of that branch of science he has probably no equal in the US. and he is understood to be qualified to take the necessary astronomical observations. the thing to be guarded against is that an indulgence to his principal qualification may not lead to a degeneracy of our mission to a search for gold and silver mines. these are but an incidental object, to be noted if found in their way, as salt, or coal or lime would, but not to be sought after. referring therefore what now remains to be done to your kind assistance, I tender you my friendly salutations & assurances of great esteem & respect.