A favorable and a confidential opportunity offering by Mr. Dupont de Nemours, who is revisiting his native country, gives me an opportunity of sending you a cypher to be used between us, which will give you some trouble to understand, but, once understood, is the easiest to use, the most indecypherable, and varied by a new key with the greatest facility of any one I have ever known. I am in hopes the explanation inclosed will be sufficient.

Let our key of letters be 6.5.1.2.7.9.8.4.3 | 9.2.3.1.7.8.5.4.6 | 3.1.4.2.8.5.7.6.9. & the key of lines be 9.4.7.6.1.8.5.2.3 | 2.1.8.9.6.5.7.3.4 | 7.6.9.3.1.2.4.5.8.

and lest we should happen to lose our key or be absent from it, it is so formed as to be kept in the memory and put upon paper at pleasure; being produced1 by writing our names & residences at full length, each of which containing 27. letters is divided into 3. parts of 9 letters each;2 each of the 9. letters is then numbered according to the place it would hold if the 9 were arranged alphabetically. thus.

6. 5. 1. 2. 7. 9. 8. 4. 3. | 9. 2. 3. 1. 7. 8. 5. 4. 6. | 3. 1. 4. 2. 8. 5. 7. 6. 9. r o b e r t r l i | v i n g s t o n o | f c l e r m o n t 9. 4. 7. 6. 1. 8. 5. 2. 3. | 2. 1. 8. 9. 6. 5. 7. 3. 4. | 7. 6. 9. 3. 1. 2. 4. 5. 8. t h o m a s j e f | f e r s o n o f m | o n t i c e l l o

robertrli alphabetically arranged would be

1. 2. 3. 4. 5. 6. 7. 8. 9. b e i l o r r r t

the numbers over the letters being then arranged as the letters to which they belong stand in our names, we can always construct our key. but why a cypher between us, when official things go naturally to the Secretary of state, and things not political need no cypher? 1. matters of a public nature, and proper to go on our records, should go to the Secretary of state. 2. matters of a public nature not proper to be placed on our records may still go to the Secretary of state, headed by the word ‘private.’ but. 3. there may be matters merely personal to ourselves, and which require the cover of a cypher more than those of any other character. this last purpose, and others which we cannot foresee may render it convenient & advantageous to have at hand a mask for whatever may need it. but writing by mr Dupont, I need use no cypher. I require from him to put this into your own & no other hand, let the delay occasioned by that be what it will.

The cession of Louisiana & the Floridas by Spain to France works most sorely on the US. on this subject the Secretary of state has written to you fully. yet I cannot forbear recurring to it personally, so deep is the impression it makes in my mind. it compleatly reverses all the political relations of the US. and will form a new epoch in our political course. of all nations of any consideration France is the one which hitherto has offered the fewest points on which we could have any conflict of right, and the most points of a communion of interests. from these causes we have ever looked to her as our natural friend, as one with which we never could have an occasion of difference. her growth therefore we viewed as our own, her misfortunes ours. there is on the globe one single spot, the possessor of which is our natural & habitual enemy. it is New Orleans, through which the produce of three eighths of our territory must pass to market, and from it’s fertility it will ere long yield more than half of our whole produce and contain more than half our inhabitants. France placing herself in that door assumes to us the attitude of defiance. Spain might have retained it quietly for years. her pacific dispositions, her feeble state, would induce her to increase our facilities there, so that her possession of the place would be hardly felt by us, and it would not perhaps be very long before some circumstance might arise which might make the cession of it to us the price of something of more worth to her. not so can it ever be in the hands of France. the impetuosity of her temper, the energy & restlessness of her character, placed in a point of eternal friction with us, and our character, which though quiet, & loving peace & the pursuit of wealth, is high minded, despising wealth in competition with insult or injury, enterprizing & energetic as any nation on earth, these circumstances render it impossible that France and the US. can continue long friends when they meet in so irritable a position. they as well as we must be blind if they do not see this; and we must be very improvident if we do not begin to make arrangements on that hypothesis. the day that France takes possession of N. Orleans fixes the sentence which is to restrain her forever within her low water mark. it seals the union of two nations who in conjunction can maintain exclusive possession of the ocean. from that moment we must marry ourselves to the British fleet & nation. we must turn all our attentions to a maritime force, for which our resources place us on very high ground: and having formed and cemented together a power which may render reinforcement of her settlements here impossible to France, make the first cannon which shall be fired in Europe the signal for tearing up any settlement she may have made, and for holding the two continents of America in sequestration for the common purposes of the United British & American nations. this is not a state of things we seek or desire. it is one which this measure, if adopted by France, forces on us, as necessarily as any other cause, by the laws of nature, brings on it’s necessary effect. it is not from a fear of France that we deprecate this measure proposed by her. for however greater her force is than ours compared in the abstract, it is nothing in comparison of ours when to be exerted on our soil. but it is from a sincere love of peace, and a firm persuasion that bound to France by the interests and the strong sympathies still existing in the minds of our citizens, and holding relative positions which ensure their continuance we are3 secure of a long course of peace. whereas the change of friends, which will be rendered necessary if France changes that position, embarks us necessarily as a belligerent power in the first war of Europe. in that case France will have held possession of New Orleans during the interval of a peace, long or short, at the end of4 which it will be wrested from her. will this shortlived possession have been an equivalent to her for the transfer of such a weight into the scale of her enemy? will not the amalgamation of a young, thriving, nation continue to that enemy the health & force which are at present so evidently on the decline? and will a few years possession of N. Orleans add equally to the strength of France? she may say she needs Louisiana for the supply of her West Indies. she does not need it in time of peace, and in war she could not depend on them because they would be so easily intercepted. I should suppose that all these considerations might in some proper form be brought into view of the government of France. tho’ stated by us, it ought not to give offence; because we do not bring them forward as a menace, but as consequences not controulable by us, but inevitable from the course of things. we mention them not as things which we desire by any means, but as things we deprecate; and we beseech a friend to look forward and to prevent them for our common interests.

If France considers Louisiana however as indispensable for her views she might perhaps be willing to look about for arrangements which might reconcile it to our interests. if any thing could do this it would be the ceding to us the island of New Orleans and the Floridas. this would certainly in a great degree remove the causes of jarring & irritation between us, and perhaps for such a length of time as might produce other means of making the measure permanently conciliatory to our interests & friendships. it would at any rate relieve us from the necessity of taking immediate measures for countervailing such an operation by arrangements in another quarter. but still we should consider N. Orleans & the Floridas as no equivalent for the risk of a quarrel with France produced by her vicinage.5—I have no doubt you have urged these considerations on every proper occasion with the government where you are. they are such as must have effect if you can find the means of producing thorough reflection on them by that government. the idea here is that the troops sent to St. Domingo, were to proceed to Louisiana after finishing their work in that island. if this were the arrangement, it will give you time to return again & again to the charge. for the conquest of St. Domingo will not be a short work. it will take considerable time and wear down a great number of souldiers. every eye in the US. is now fixed on this affair of Louisiana.6 perhaps nothing since the revolutionary war has produced more uneasy sensations through the body of the nation. notwithstanding temporary bickerings have taken place with France, she has still a strong hold on the affections of our citizens generally.—I have thought it not amiss, by way of supplement to the letters of the Secretary of state, to write you this private one to impress you with the importance we affix to this transaction. I pray you to cherish Dupont. he has the best dispositions for the continuance of friendship between the two nations, and perhaps you may be able to make a good use of him. accept assurances of my affectionate esteem & high consideration.