Thomas Jefferson Papers

To Thomas Jefferson from Robert Patterson, 30 December 1805

Philada. Decr. 30th 1805—


Some years ago, I remember to have laid before you a scheme of secret writing, which you were pleased to honour with a friendly notice: And relying on your well-tried patience; I would again take the liberty of submitting a few further remarks on the same subject.

That scheme, in common with all others heretofore practised, had one defect, which it is the object of the present attempt to supply.—

When a letter of this kind happens to be interupted, it immediately discovers what it is; and, whether decyphered or not, will certainly fail of answering the design of the writer. Whereas if this circumstance were concealed, and the letter appeared perfectly innocent, and especially if it appeared (as it might always do) to be written by the wife, or some other near relative, of the person to whom it was addressed, the common politeness, even of an enemy, would most frequently secure it a safe passport—Some attempts of this kind have indeed been made, as may be seen in the Encyclopedia, and in other works, but all of so clumsey a nature, as not to deserve attention, much less imitation.

In our written alphabet, there are two letters, the i and the t, to which belong adjuncts, generally made by a second operation of the pen, after the body of the letter has been formed: And very happily for this scheme, these letters occur in the English language, and perhaps in most of the other European languages, almost as frequently as any other letters in the alphabet.

These adjuncts, in common free writing, & without any design, appear under a great variety of different forms & positions; and it is this variety that constitutes the basis of the present system—the adjuncts themselves, signifying the letters &c of the secret writing. It is here that according to this scheme, a small part only of the ostensible letter (the i’s & t’s) will be employed in the secret correspondence—This, however, will not generally be much of an inconvenience. Since, as you once observed, one frequently wants to express only a few words in cypher. But if this should still be considered as an imperfection, it may in a great measure be remedied, & indeed the system in other respects improved, in the following way—As in short-hand, so in secret writing, let true orthography be entirely disregarded; such letters only being expressed as, with the general scope & connection of the sentence, may be sufficient to designate the word. In words of the most frequent occurence, a single letter, will generally be sufficient for this purpose—either the initial letter, or that whose sound predominates in the word.

As the adjuncts of the i & t are susceptible of 40 or 50 varieties, readily distinguishable from each other, and yet so little different from the common practice of free writing as to excite no suspicion of design, 26 of them may be appropriated to represent the letters of the English alphabet, 3 or 4 to represent double letters, 1 to represent a space between words, and the rest to represent the words respectively of most frequent occurrence. By this means the quantity of secret writing may be made to extend to little less than ⅓ of the ostensible vehicle of common writing

The adjuncts of the i (including the j) may be varied in form eight or more different ways viz. the strong dot (.) the weak dot (.) the small dash, horizontal (-), vertical (|), oblique descending to the right (\) oblique descending to the left (/) the comma (,) the reversed comma (,) and the acute accent (´) and each of these may be varied in position six different ways, viz. It may be placed at a small, or at a greater distance above the body of the letter; and this either directly above, or to the right, or to the left, of the body of the letter.

The adjuncts of the t may be confined to the straight line—This however may be of two different magnitudes viz. short & long. Each of these may be varied in position 28 different ways viz. It may be drawn either near the line of writing, or at a greater distance above it. It may be either parallel to the line of writing, or it may diverge a little from it towards the right. It may cross the stem of the letter having an equal portion on each side, or a greater portion of the stroke may be on the right of the stem than on the left, or on the left than on the right. It may just touch the stem on the right, or on the left, but not cross it. Or lastly it may in fact not touch it at all, but be wholly on the right, or on the left.

In appropriating the above adjuncts to the letters & of the secret alphabet, it may not be amiss to make those adjuncts which are the most natural & usual in common writing, represent the letters &c of the most frequent occurrence. Upon this principle the following table is attempted. It may, however, be varied at pleasure, without any great inconvenience—I have in this specimen confined myself to 30 adjuncts of each letter viz. one for each letter of the alphabet, one for the double letter th & three for the words the, and, of: the omission of the adjunct being made to signify a space between words: which, however, need not be used either immediately before or after the verbal adjuncts for the, and or of. Two of these characteristicks for a space, coming together, may signify the end of a sentence; & three in succession, may signify the end of the secret communication: after which the adjuncts in the remaining part of the letter may be made at pleasure. It is to be observed that where two t’s come together in the same word the latter of them only is to be considered as significant—Since using different adjuncts to two adjoining letters might possibly create a suspicion of design.

In the annexed table it will be observed that of the adjuncts of the i there are only inserted 5 different forms viz. the dot without distinction of large & small, the horizontal dash or hyphen, the comma, the dash descending to the right or grave accent, and the acute accent.

Of the adjuncts of the t it will be observed that when the stroke is unequally divided by the stem of the letter the greater portion is always on the viz. and that the two last viz. for q & z are distinguished from the others only by being divergent & not touching the stem of the letter.

When a secret communication is to be made, the ostensible letter is first to be written, on any common or unsuspicious subject; taking care to omit all the adjuncts of the i’s & t’s Then taking the lines in any order, & either backward or forwards, as may have been previously agreed upon by the correspondents, let the adjuncts proper to express the secret communication be supplied with the utmost care and attention; but with as much seeming freedom as is consistent with perspecuity

For example—Suppose the following to be the secret commn.

The conduct of Spain towards the U.S. must no longer be practised with impunity. War has become unavoidable. Demand your passport, & return as soon as possible.—In short-hand spelling thus—The cndc of spn/twrds the U.S. mst no lngr b prctsd with impun. Wr s unavdble. Dmnd yr psprt, and rtrn s sn s psbl—

And suppose the vehicle of this order to be the following account of a machine now about to erected in this city and that in marking the secret message the lines are to be taken in their natural order, and read forwards.

The adjuncts being supplied it would appear thus—


As you always take a lively interest in the progress of the useful arts in your native country you will no doubt be gratified to hear that a certain Mr. Hawkins, I believe a native of the state of N.Y. has lately invented, & is now constructing in the city of Philadelphia, a machine for planing board, or scantling: the machine is simple in its construction will be but little liable to get out of repair, & may be erected at a trifling expence the inventor computes, that with the force of a single horse, his machine; which will require but one man to attend it, will readily do as much work as sixty men in the ordinary way of manual labour.

A little practice would render this scheme very easy both in writing & reading, & would, it is believed, be impossible to decypher. I have the honour to be with the greatest esteem

Your most obedt. servant

R. Patterson

If the inclosed system of secret writing should be thought to deserve any attention—The President may be assured that it is known only to himself and the writer—

DLC: Papers of Thomas Jefferson.

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