On March 4, 1801, Jefferson was inaugurated President of the United States, and immediately started his plans for the Lewis and Clark expedition. Less than two weeks before his inauguration, on February 23, he had written to Meriwether Lewis to offer him the position of his secretary, and in listing his qualifications mentioned: “ . . . your knolege of the Western country, of the army and of all it’s interests & relations has rendered it desireable for public as well as private purposes that you should be engaged in that office . . . ”

Lewis’s letter accepting the secretaryship is dated from Pittsburgh, March 10, 1801.

On January 18, 1803, Jefferson addressed a special message to Congress, concerning the lands adjacent to the Mississippi and Missouri rivers, and the Indians occupying them: “ . . . we possess what is below the Yazoo, & can probably acquire a certain breadth from the Illinois & Wabash to the Ohio. but between the Ohio and Yazoo, the country all belongs to the Chickasaws, the most friendly tribe within our limits, but the most decided against the alienation of lands. the portion of their country most important for us is exactly that which they do not inhabit. their settlements are not on the Missisipi, but in the interior country. they have lately shewn a desire to become agricultural, and this leads to the desire of buying implements & comforts. in this strengthening and gratifying of these wants, I see the only prospect of planting on the Missisipi itself the means of its own safety. Duty has required me to submit these views to the judgment of the legislature. but as their disclosure might embarras & defeat their effect, they are committed to the special confidence of the two houses . . . an intelligent officer with ten or twelve chosen men, fit for the enterprize and willing to undertake it, taken from our posts, where they may be spared without inconvenience, might explore the whole line, even to the Western ocean, have conferences with the natives on the subject of commercial intercourse, get admission among them for our traders as others are admitted, agree on convenient deposits for an interchange of articles, and return with the information acquired in the course of two summers.

" their arms and accoutrements, some instruments of observation, & light & cheap presents for the Indians would be all the apparatus they could carry, and with an expectation of a soldier’s portion of land on their return, would constitute the whole expence. their pay would be going on, whether here or there. while other civilised nations have encountered great expence to enlarge the boundaries of knowledge, by undertaking voiages of discovery, & for other literary purposes, in various parts and directions, our nation seems to owe to the same object, as well as to its own interests, to explore this, the only line of easy communication, across the continent, and so directly traversing our own part of it. the interests of commerce place the principal object within the constitutional powers and care of Congress and that it should incidentally advance the geographical knowledge of our own continent, cannot but be an additional gratification. the nation claiming the territory, regarding this as a literary pursuit which it is in the habit of permitting within it’s dominions, would not be disposed to view it with jealousy, even if the expiring state of its interests there did not render it a matter of indifference. The appropriation of two thousand five hundred dollars ‘for the purpose of extending the external commerce of the US,’ while understood and considered by the Executive as giving the legislative sanction, would cover the undertaking from notice, and prevent the obstructions which interested individuals might otherwise previously prepare in it’s way. ”

Before February 25 he was looking for a secretary to replace Meriwether Lewis; this office was declined by William Brent in a letter to Lewis of that date.

On February 28, Jefferson wrote to Benjamin Rush: “ I wish to mention to you in confidence that I have obtained authority from Congress to undertake the long desired object of exploring the Missouri & whatever river, heading with that, leads into the Western ocean. about 10. chosen woodsmen headed by Capt. Lewis my secretary, will set out on it immediately & probably accomplish it in two seasons. Capt. Lewis is brave, prudent, habituated to the woods, & familiar with Indian manners & character. he is not regularly educated, but he possesses a great mass of accurate observation on all the subjects of nature which permit themselves here, & will therefore readily select those only in his new route which shall be new. he has qualified himself for those observations of longitude & latitude necessary to fix the points of the line he will go over. it would be very useful to state for him those objects on which it is most desireable he should bring us information. for this purpose I ask the favor of you to prepare some notes of such particulars as may occur in his journey & which you think should draw his attention & enquiry. he will be in Philadelphia about 2. or 3. weeks hence & will wait on you . . . ”

Benjamin Rush sent Jefferson the rules, which Jefferson copied out in his own hand and sent to Lewis, as follows: “ D ^r. Rush to Capt. Lewis. for preserving his health. June 11. 1803.

" 1. when you feel the least indisposition, do not attempt to overcome it by labour or marching. rest in a horizontal posture.--also fasting and diluting drinks for a day or two will generally prevent an attack of fever. to these preventatives of disease may be added a gentle sweat obtained by warm drinks, or gently opening the bowels by means of one, two, or more of the purging pills.

" 2. unusual costiveness is often a sign of approaching disease. when you feel it take one or more of the purging pills.

" 3. want of appetite is likewise a sign of approaching indisposition. it should be obviated by the same remedy.

" 4. in difficult & laborious enterprizes & marches, eating sparingly will enable you to bear them with less fatigue & less danger to your health.

" 5. flannel should be worn constantly next to the skin, especially in wet weather.

" 6. the less spirit you use the better, after being wetted or much fatigue, or long exposed to the night air, it should be taken in an undiluted state. 3 tablespoonfuls taken in this way will be more useful in preventing sickness, than half a pint mixed with water.

" 7. molasses or sugar & water with a few drops of the acid of vitriol will make a pleasant & wholesome drink with your meals.

" 8. after having had your feet much chilled, it will be useful to wash them with a little spirit.

" 9. washing the feet every morning in cold water, will conduce very much to fortify them against the action of cold.

" 10. after long marches, or much fatigue from any cause, you will be more refreshed by lying down in a horizontal posture for two hours, than by resting a much longer time in any other position of the body.

" 11. shoes made without heels, by affording equal action to all the muscles of the legs, will enable you to march with less fatigue, than shoes made in the ordinary way.”

On the same day, February 28, that he had written to Rush, Jefferson wrote to Caspar Wistar: “ . . . What follows is to be perfectly confidential. I have at length succeeded in procuring an essay to be made of exploring the Missouri & whatever river, heading with that, runs into the Western ocean. Congress by a secret authority enables me to do it. a party of about 10. chosen men headed by an officer will immediately set out. we cannot in the U. S. find a person who to courage, prudence, habits & health adapted to the woods, & some familiarity with the Indian character, joins a perfect knolege of botany natural history, mineralogy & astronomy, all of which would be desireable.

" to the first qualifications Capt. Lewis my secretary adds a great mass of accurate observation made on the different subjects of the three kingdoms as existing in these states, not under their scientific forms, but so as that he will readily sieze whatever is new in the country he passes thro, and give us accounts of new things only: and he has qualified himself for fixing the longitude & latitude of the different points in the line he will go over. I have thought it would be useful to confine his attention to those objects only on which information is most deficient & most desireable: & therefore would thank you to make a note on paper of those which occur to you as most desireable for him to attend to. he will be in Philadelphia within two or three weeks & will call on you. any advice or hints you can give him will be thankfully recieved & usefully applied. I presume he will compleat his tour there & back in two seasons . . . ”

On April 20 Meriwether Lewis addressed to Jefferson from Lancaster a long letter of 5 pages, explaining all the arrangements he had made for the expedition. The letter opens: “With a view to forward as much as possible the preparations which must necessarily be made in the Western country previous to my final departure, as also to prevent the delay, which would attatch to their being made after my arrival in that quarter, I have taken the following measures, which I hope will meet your approbation; they appear to me to be as complete as my present view of the subject will admit my making them, and I trust the result will prove as favorable as wished for . . .”

The last paragraphs read: “I arrived at this place yesterday, called on M ^r. Ellicot, and have this day commenced, under his direction, my observations & ^c, to perfect myself in the use and application of the instruments.

"M ^r. Ellicot is extreemely friendly and attentive and I am confident is disposed to render me every aid in his power: he thinks it will be necessary I should remain here ten or twelve days.--

"Being fully impressed with the necessity of seting out as early as possible, you may rest assured that not a moment shall be lost in making the necessary preparations. I still think it practicable to reach the mouth of the Missourie by the 1 ^st. of August.--”

In the Jefferson Papers in the Library of Congress is an undated document in the handwriting of Lewis headed: Recapitulation of an estimate of the sum necessary to carry into effect the Miss ^ie expedicion.

This reads as follows:

Mathematical Instruments............................................................................$217.--

Arms & Accoutrements extraordinary...............................................................81.--

Camp Ecquipage..............................................................................................255.--

Medecine & packing..........................................................................................55.--

Means of transportation...................................................................................430.--

Indian presents.................................................................................................696.--

Provisions extraordinary...................................................................................224.--

Materials for making up the various articles into portable packs.......................55.--

For the pay of hunters guides & Interpreters...................................................300.--

In silver coin to defray the expences of the party from Nashville to the last white settlement on the Missesourie..............................................$100.--

Contingencies.....................................................................................................87.--

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Total...........................................................................................................$2,500.--

The Jefferson Papers also contain, in Jefferson’s handwriting, the Cypher establ ^d. with Captain Lewis. key. Artichokes.

Meanwhile, on April 23, before he had received Lewis’s letter, Jefferson had written to him: “ I have not been able to hear any thing of you since Mar. 7. till two or three days ago. Lieut ^t. Wilson told me you would leave Frederic the 18 ^th. inst. & that you had been detained till then at Harper’s ferry, where Capt Murray also told me he had seen you. I have no doubt you have used every possible caution to get off, and therefore we have only to lament what cannot be helped, as the delay of a month more may lose a year in the end.--will you be so good as to call on Doct ^r. Bollman with my compliments & pay him for some wine sent me? I suppose it will be about 12. Doll. but it must be whatever he says. I will also thank you to purchase for me a Leopard or tyger’s skin, such as the covers of our saddles were cut out of. in North 3 ^d. street & North 4 ^th. street a few doors only from Market street there used to be a considerable furrier’s store in each. at one of these it was that I saw a robe of what they called the Peruvian sheep, and I took to be of the Lama or Vigogna. it was made up of several skins, & was of the price of 12.D. if ther [sic.-- Ed.] be such a thing there now, you can either observe & report it to me, or if you think it good (for I have almost forgot it) I would take it at once. let me hear from you on your reciept of this, and inform me of your prospect for getting off. I have letters here for you from your friends in Albemarle. Accept my affectionate salutations. ”

After receiving Lewis’s letter, Jefferson wrote, on April 27: “ Your’s of the 20 ^th. from Lancaster was recieved the night before last. not having heard from you since the time of my leaving Washington, I had written to you on the 23 ^d. and lodged it in Philadelphia.

" you will therefore probably recieve that & this together. I inclose you a copy of the rough draught of instructions I have prepared for you, that you may have time to consider them, & to propose any modifications which may occur to yourself as useful. your destination being known to m ( ^~ r) Patterson, Doct ^rs. Wistar, Rush & Barton, these instructions may be submitted to their perusal. a considerable portion of them being within the field of the Philosophical society, which once undertook the same mission, I think it my duty to consult some of it’s members, limiting the communication by the necessity of secrecy in a good degree. these gentlemen will suggest any additions they will think useful, as has been before asked of them.--we have recieved information that Connor cultivates in the first degree the patronage of the British government; to which he values ours as only secondary. as it is possible however that his passion for this expedition may overrule that for the British, and as I do not see that the British agents will necessarily be disposed to counterwork us, I think Connor’s qualifications make it desireable to engage him, and that the communication to him will be as useful, as it was certainly proper under our former impression of him. the idea that you are going to explore the Missisipi has been generally given out: it satisfies public curosity, [ sic -- Ed. ] and masks sufficiently the real destination. I shall be glad to hear from you, as soon after your arrival at Philadelphia as you can form an idea when you will leave, & when be here. accept assurances of my constant & sincere affection. ”

Three days later, on April 30, Jefferson sent further instructions to Lewis: “ I think we spoke together of your carrying some cast iron corn mills to give to the Indians or to trade with them, as well as for your own use. lest however I should be mistaken, I mention them now. I make no doubt you have consulted with m ( ^~ r) Ellicot as to the best instruments to carry. I would wish that nothing which passed between us here should prevent your following his advice, which is certainly the best. should a time-piece be requisite, it is probable m ( ^~ r) Garnet can furnish you one. neither Ellicot nor Garnet have given me their opinion on the substituting a meridian at land, instead of observations of time, for ascertaining longi- tude by the lunar motions. I presume therefore it will not answer. accept my affectionate salutations.”

On May 14 Lewis wrote to Jefferson from Philadelphia: “In your instructions to me you mention that the instruments for ascertaining by celestial observations the geography of the country through which I shall pass, have been already provided: I shall not therefore purchase any articles on that discription untill I hear further from you on this subject. Will you be so good as to inform me what instruments have been provided? and where they are?--it may be possible that some instrument has been omitted, which M ^r. Patterson, M ^r. Ellicott and those gentlemen to whom you have referred me in this place, may deem necessary for me, and if so the deficiency can be supplyed in time.--

"M ^r. Patterson and M ^r. Ellicott both disapprove of the Theodolite as applicable to my purposes; they think it a delicate instrument, difficult of transportation, and one that would be very liable to get out of order; they also state that in it’s application to any observations for obtaining the Longitude, it would be liable to many objections and to much more inacuracy than the Sextant--The instruments these gentlemen recommend, and which indeed they think indispensibly necessary, are, two Sextants, (one of which, must be constructed for the back observation), an artificial Horizon or two; a good Arnald’s watch or Chronometer, a Surveyor’s Compass with a ball and socket and two pole chain, and a set of plotting instruments.--By means of the Sextant fixed for the back observation and an artificial Horizon also constructed for the purpose; the meridian altitude of the Sun may always be taken, altho it should even exceed eighty degrees: for this valuable problem I am indebted to M ^r. Patterson.--

"As a perfect knolege of the time will be of the first importance in all my Astronomical observations, it is necessary that the time-keeper intended for this expedition should be put in the best possible order, if therefore Sir, one has been procured for me, and you are not perfectly assured of her being in good order, it would be best perhaps to send her to me by some safe hand, (should any such conveyance offer in time); M ^r. Voit could then clean her, and M ^r. Ellicott has promised to regulate her, which, I believe he has the means of doing just now, more perfectly than it can be done any where else in the UStates.--

"I cannot yet say what day it will be in my power to leave this place.--Your different orders have been attended to, and the result you shall have in a day or two.”

Jefferson answered this from Washington on May 16: “ yours of the 14 ^th. is this moment recieved, & I hasten to answer it by return of post, that no time may be lost. the copy of instructions sent you are only a rough draught for consideration. they will not be signed or dated till your departure. presuming you would procure all the necessary instruments at Philadelphia, which is a principal object of your journey there, the instructions say that the necessary instruments ‘ have been provided’, which will be true when they recieve their ultimate form, date & signature, tho’ nothing was provided at the time of writing the rough draught. this will serve to correct the impression which has been misunderstood, and to let you know you are relied on to provide every thing for yourself.--with respect to the Theodolite, I wish you to be governed entirely by the advice of m ( ^~ r) Patterson & m( ^~ r) Ellicott. as also as to the time piece & whatever else they think best. m( ^~ r) Garnett told us he had some good ones still on hand; which I remind you of, lest you should not be able to get one in Philadelphia. accept my affectionate salutations. ”

On May 29, Lewis wrote to say that he would be ready to leave Washington on June 6 or 7 and that he had done Jefferson’s shopping as requested in his letter of April 23: “I have at length so far succeeded in making the necessary preparations for my intended journey as to be enabled to fix on the sixth or seventh of June as the probable time of my departure for Washington. All the article [ sic -- Ed. ] have been either procured, or are in such state of forwardness in the hands of the workmen as to induce me to to M ^r. Gallatin, that I have not been able to procure Danvill’s map--The maps attatched to Vancouver’s voyage cannot be procured seperately from that work, which is both too costly, and too weighty, for me either to purchase or carry.--”

On June 20, Jefferson wrote his official instructions to Lewis. In the Jefferson Papers in the Library of Congress is a letterpress copy of this document, consisting of four closely written pages, headed: To Meriwether Lewis esquire, Captain of the 1 ^st. regiment of infantry of the United States of America. This document gives full and complete instructions as to the carrying out of the enterprise in every detail. It closes: Given under my hand at the city of Washington this 20 ^th. day of June 1803 / Th: Jefferson Pr. US. of America

On July 3, Jefferson wrote concerning Lewis’s expedition to Henri Peyroux de la Coudrenière, the Spanish commandant at St. Genevieve: “ Since I had the pleasure of your acquaintance in Philadelphia in 1791. I had suppozed you were returned to Europe. I have lately however been told that you preside at present at S ^te Genevieve & S ^t. Louis. I cannot therefore omit the satisfaction of writing to you by Cap ^t. Lewis, an officer in our army, & for some time past my Secretary. as our former acquaintance was a mixt one of science and business, so is the occasion of renewing it. you know that the geography of the Missouri and the most convenient water communication from the head of that to the Pacific ocean is a desideratum not yet satisfied. since coming to the administration of the US. I have taken the earliest opportunity in my power to have that communication explored, and Capt Lewis with a party of twelve or fifteen men is authorised to do it. his journey being merely literary, to inform us of the geography & natural history of the country, I have procured a passport for him & his party, from the Minister of France here, it being agreed between him & the Spanish minister, that the country having been ceded to France, her minister may most properly give the authority for the journey. this was the state of things when the passport was given, which was some time since. but before Capt Lewis’s actual departure we learn through a channel of unquestionable information that France has ceded the whole country of Louisiana to the US. by a treaty concluded in the first days of May. but for an object as innocent & useful as this I am sure you will not be scrupulous as to the authorities on which this journey is undertaken; & that you will give all the protection you can to Capt Lewis & his party in going & returning. I have no doubt you can be particularly useful to him, and it is to sollicit your patronage that I trouble you with the present letter, praying you at the same time to accept my friendly salutations and assurances of my high respect & consideration. ”

On July 4, Jefferson wrote to Lewis, now at Harper’s Ferry: “ In the journey which you are about to undertake for the discovery of the course and source of the Missouri, and of the most convenient water communication from thence to the Pacific ocean, your party being small, it is to be expected that you will encounter considerable dangers from the Indian inhabitants.

" should you escape those dangers and reach the Pacific ocean, you may find it imprudent to hazard a return the same way, and be forced to seek a passage round by sea, in such vessels as you may find on the Western coast. but you will be without money, without clothes, & other necessaries; as a sufficient supply cannot be carried with you from hence. your resource in that case can only be in the credit of the US. for which purpose I hereby authorise you to draw on the Secretaries of State, of the Treasury, of War & of the Navy of the US. according as you may find your draughts will be most negociable, for the purpose of obtaining money of necessaries for yourself & your men: and I solemnly pledge the faith of the United States that these draughts shall be paid punctually at the date they are made payable. I also ask of the Consuls, agents, merchants & citizens of any nation with which we have intercourse or amity to furnish you with those supplies which your necessities may call for, assuring them of honorable and prompt retribution, and our own Consuls in foreign parts where you may happen to be, are hereby instructed & required to be aiding & assisting to you in whatsoever may be necessary for procuring your return back to the United ”