At a glanceCiphertext-only break · complete
- The letters
- Aaron Burr to his daughter Theodosia Burr Alston: a cover note of 10 February, a copy of his letter of 31 January, and a short letter of 18 February, all from Baltimore. The year is not written in the cipher; a docket on one sheet reads “Balt.” and “1808”.
- Where
- Gilder Lehrman Collection, GLC01523, where the two sheets are counted as pages two and three of Burr’s July 1804 letter to Joseph Alston; one is pencilled “1523A”. That letter has its own short cipher and its own page.
- The cipher
- A Vigenère over the alphabet numbered a = 1 to z = 26, with a six-place key (shifts 6, 18, 22, 7, 24, 8) that runs on through the letters and starts again at each section. The numbers of a word are joined by commas; words are kept apart.
- How it was read
- The key was recovered from the numbers alone: the index of coincidence rises at period six, and fitting each of the six columns to English letter frequencies gives the shifts. A control text of the same length, enciphered with 20 random keys, is broken by the same method every time.
- What it says
- Burr, “at Baltimore incog.”, still means to visit her secretly at The Oaks (“let it be believed, except by mari, that I am in Philadelphia”) and waits “hourly” for “money for the long voyage”.
- Still open
- One group of four numbers on the 18 February sheet, rubbed on a fold.
01 The sheets
Gilder Lehrman’s catalogue describes GLC01523, Burr’s letter to Joseph Alston of July 1804, as three pages of which “the second and third pages are in cypher”, and the Institute’s Hamilton Education Program shows the cipher as part of that letter, “not yet decoded”. The July letter does carry a cipher, ten lines of figures and stroke signs on its clear page, read on its own page. The two sheets of numbers are something else.
The larger sheet (pencilled “1523A” at the foot) is written full in three sections divided by ruled lines. The first section begins “Below the black line is copy of my last” and is dated in the text “the tenth February”; the second is that copy, the letter of “this blessed thirty first day of January”; the third, below the second line, is the end of it. The smaller sheet has three lines at its head, the letter of 18 February, and a docket in another hand: “Balt.” and “1808”.
The year fits nothing but 1808. After his acquittal at Richmond in September 1807 Burr went east, was hanged in effigy by a crowd at Baltimore in November, and spent the winter out of public view while he raised money to go to Europe; he sailed from New York for England on 7 June 1808. Theodosia, often ill, was with her husband in South Carolina. The letters are to her, not to Alston: “the hope of seeing me keeps you at the Oaks at the hazard of your life”, “except by mari” (French, her husband), and the pet name “huzzey” at the end of the copy. “Gamp” is Burr himself, as in the journal he later kept for her in Europe.
02 The reading
Burr writes no punctuation in the cipher; it is added here. Spelling as enciphered. [?] marks a word read against one number that disagrees with the key; [s] a letter Burr left out.
Baltimore, 10 February [1808]
Below the black line is copy of my last, by the schooner Wolf, Capt. Jones, to sail about the eighteenth. You will hear again. Keep up your spirits. My plans are not changed. Yet at Baltimore incog., the tenth February. Business now detains me. We must submit, submit, submit to ten days more of suspense. The promise in[?] my last was rashly made. Affairs begin to look up. J’y travaille. What would Gamp not give to know that you are all well.
Copy of the letter of 31 January [1808]
My last letter was written eight days ago. Poor Gamp is still at Baltimore on this blessed thirty-first day of January, still hoping and still persisting in all the plans so often written to you. It distresses me to think that the hope of seeing me keeps you at the Oaks at the hazard of your life. Indeed my be[s]t endeavors are used and shall be used to get to you. If after ten days further delay it be found impracticable, a person shall be sent express to you, and for you just four hours work, huzzey.
No person must suspect that I mean to visit you in S.C. Let it be believed, except by mari, that I am in Philadelphia.
Baltimore, 18 February [1808]
Baltimore, eighteenth Feb. Nothing new. The same hopes and intentions continue. Have[?] patience. [four numbers rubbed] hourly expectation of money for the long voyage, and nothing else detains[?] me.
“J’y travaille” is French, “I am working at it”. The plan of the copy is a secret journey south: Burr would come to The Oaks himself, or, if that proved impossible after ten more days, send an express. By 18 February the journey is not mentioned; only the money for “the long voyage” keeps him.
03 The cipher
Each letter is numbered a = 1 to z = 26 and shifted by one of six amounts in turn:
| key place | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| shift | 6 | 18 | 22 | 7 | 24 | 8 |
| a is written | 7 | 19 | 23 | 8 | 25 | 9 |
Cipher number = letter number + shift, counted round from 26 to 1. The key moves on with every letter, not with every word, and starts again at the head of each section; the same word therefore looks different in different places, except when it falls at the same key place, as submit (26,19,10,19,1,16) does three times running. No keyword lies behind the six shifts (as letters, a = 0: G S W H Y I).
04 How it was deciphered
- The note of 10 February (80 words, 341 numbers) was transcribed first. All 26 values occur and the commonest has only 8.5% of the text: not a simple substitution. Some words could not be English under one alphabet (a doubled number in
21,11,23,23;3,22and23,12as two-letter words). - The index of coincidence is 0.0435 for the whole and 0.0618 for every sixth number: a six-place key.
- For each of the six columns, the shift that best fits English letter frequencies (chi-square) was taken. The note read at once: “below the black line is copy of my last by the schooner wolf”.
- The rest was transcribed and reads with the same key. Two places fell out of step. A pass over the words scored with an English language model found them: Burr wrote
10,11,16for best, leaving out the s but moving the key on; and on the 18 February sheet the rubbed group stands before a fall-back of one key place. - Control: Burr’s own letter of 18 July 1804 (Davis’s text), cut to 341 letters and enciphered with 20 random six-place keys, is broken by the same method 20 times out of 20.
- A statistical check (
docs/_validate.py, tokens tagged by key place): −2.21 per letter against −7.47 for 200 random keys and −4.18 for keys refitted to shuffled text: a pass.
05 What remains uncertain
- 18 Feb, before “hourly”: four numbers, the second rubbed on a fold (read 2?, 11?, 1, 23). No word fits at any key place; “in” would need 17, 20. Open, blocked by the image.
- in[?] (10 Feb,
15,16): gives “ix”; the key needs 15, 6. Burr’s slip or a misreading. Grade C. - have[?] and detains[?] (18 Feb): one number each disagrees with the key (11 for 14, 13 for 18), easy confusions in this hand. Grade C.
- impracticable and for (31 Jan): the last digit of one number in each is torn away at the edge; the key needs 25 and 24, and the visible 2 fits both. Grade H.
- huzzey and mari are read as written. Grade C for the gloss.
- Kline and Ryan’s edition of Burr’s papers (1983) prints no letter of January or February 1808; its editorial note “The Road to Exile” (vol. 2, p. 1040) was not read and may refer to these letters.
Full texts
The transcription and the decryption of every document on this page, so that the reading can be used and checked. Short files are shown here; all are in the repository.
Copy of the letter of 31 January [1808] (img1, sections B and C)
Burr, hiding at Baltimore, tells Theodosia he still holds to his plans, is distressed that waiting to see him keeps her at The Oaks at risk to her health, and will try to reach her or send an express; no one is to know he means to visit South Carolina, and all but her husband are to think he is in Philadelphia.
Transcription
# GLC01523, Aaron Burr to Joseph Alston. Transcription of the number cipher (Claude, 5 Nov 2026)
# Images: hamilton.gilderlehrman.org/sites/default/files/2023-10/GLC01523_Page_{1,2,3}.png
# img1 = GLC01523_Page_1.png (full page of number cipher, three sections divided by ruled lines)
# img2 = GLC01523_Page_2.png (three lines of number cipher at the head of a sheet)
# img3 = GLC01523_Page_3.png (clear page with the stroke cipher; see tally.txt)
# One token per number, numbers of a word joined by commas (Burr writes commas or dots), words separated by spaces.
# "=" at a line end / start: word runs on to the next line. "?" after a number: reading unsure.
# [ins N] = number written above the line with a caret (read as part of the word); [above N] = number written above
# with no caret (not part of the cipher; left out); [del ...] = struck through; [x] = an x-mark in the text.
# [om] = Burr left out a letter but the key moved on (B.06 "be[s]t"); [key -1] = the key falls back one place
# after an unread group (img2.02), from the phase of the words that follow.
# "-" = Burr's dash (a hooked stroke). Section breaks are the ruled lines on img1.
#
# --- img1, section A (above the first ruled line) ---
img1.A.01: 8,23,8,22,21 2,14?,23 24,19,25,11,17 4,5,21,3 17,25 21,11,23,23 23,12 5,21 19,25,1,26 - 20,21 1,6,13 25,21,4,22,13,22,11,10 19=
img1.A.02: =[ins 22],10,14 9,19,12,1: 8,23,20,23,15 ( 1,13 1,7,1,8 8,26,23,[ins 1],12 16,15,3 13,15,25,4,1,3,13,20,12,4 ) 6,13,3 3,1,8,19 6,13,7,10 23,14,25,17,20 -
img1.A.03: 3,1,12,14 3,22 17,11,2,16 1,22,1,14,16,18,1 - 19,17 12,19,25,22,25 19,14,12 12,23,26 21,4,8,12,15,11,22 - 21,12,18 9,26 20=
img1.A.04: =23,19,18,17,19,7,14,12 7,22,9,7,3: 1,6,13 26,23,10,1,6 14,11,20,14,2,25,26,5 - 20,17,26,7,22,11,11,15 21,13,5 10,23,16,8,7,22,25=
img1.A.05: =5,1 - 4,3,21,1,11,16 26,19,10,19,1,16 26,19,10,19,1,16 26,19,10,19,1,16 1,13 2,11,6 26,8,23,1 19,7,14,12 13,14 25,13,15,23,3,22,25,23 - 16,15,3
img1.A.06: 24,24,7,9,16,17,13 15,16 9,6 10,9,25,12 19,8,17 26,7,11,4,19,23 21,7,22,1 - [x] 8,[above 4]4,14,[above 6]7,1,14,26 26,13,13,1,10 1,13 20,21,7,7=
img1.A.07: =2,14 - 18?,5 12,14,8,20,9,15,4,8,12 - [above 5]21,16,7,12 19,22,19,20,10 25,23,20,14 22,21,12 3,16,20,13 26,7 7,21,13,5 26,26,23,1 23,23=
img1.A.08: =1 19,14,12 25,20,18 15,1,19,10 -
# --- img1, section B (between the ruled lines) ---
img1.B.01: 19,17 8,8,17,2 18,23,16,1,3,26 3,19,15 4,16,17,26,12,1,21 3,17,13,26,16 11,25,7,25 19,3,22 - 14,23,21,10 3,8,11,24 15,11 15,1=
img1.B.02: =7,20,18 19,16 9,25,20,26,1,9,22,16,13 21,6 16,15,7,1 8,4,1,26,17,13,10 12,4,16,16,2,5 24,5,25,17,2 10,19,21 22,4 18,7,6,17=
img1.B.03: =8,16,7 - 25,12,5,19,10 16,21,8,5,21,5 9,20,22 15,1,7,20,18 8,1,25,17,17,25,12,5,21,5 17,20 19,8,19 18,16,11 8,8,8,12,1 25,7
img1.B.04: 11,13,18,13,20 15,14,16,18,2,11,6 16,22 23,23,1 - 1,16 11,7,1,26,10,1,26,17,13,25 5,1 1,13 2,14,1,10,18 18,16,7,12 16,15,3 16=
img1.B.05: =21,8,1 22,4 1,11,23,5,21,5 21,11 3,1,12,14,1 5,7,17 8,18 2,14,23 11,8,9,1 7,12 16,15,3 16,7,18,23,25,2 23,12 17,11,2,16
img1.B.06: 20,15,24,1 - 16,12,12,11,23,26 20,23 10,11,[om],16 12,12,12,11,19,18,22,16,1 7,10,1 2,17,13,10 19,10,11 17,16,7,4,8 9,3 3,25,23,26
img1.B.07: 1,13 15,11,12 16,22 23,23,1 - 1,2 8,4,2,11,10 16,12,12 12,7,17,15 13,19,26,26,26,1,25 2,13,18,19,21 16,18 10,11 24,11,2,12,12 15,5,12,2?=
img1.B.08: =25,11,26,1,25,8,26,20,11 19,12,12,16,1,21,6 15,15,25,20,18 20,1 26,3,22,26 23,20,23,16,13,25,11 16,22 23,23,1 19,10,11 4,23,2?
img1.B.09: 17,11,2 - 8,3,25,12 2,22,19,26 14,7,17,25,17 5,21,10,7 15,19,8,6,23,21 -
# --- img1, section C (below the second ruled line) ---
img1.C.01: 20,7 12,12,16,1,21,6 9,2,17,2 25,13,15,23,[ins 3],11,26 12,4,8,18 17 19,23,23,21 18,23 2,1,15,16,18 7,21,13 5,21 17:11 - 18,23,16, 16,18
img1.C.02: 10,11 20,1,19,7,13,2,23,26 12,22,11,11,8,16 9,23 21,7,10,5 1,6,9,26 1? 23,20 7,22 22,26,5,19,25,12,11,4,12,15,7,9 -
# --- img2 ---
img2.01: 8,19,8,1,7,21,21,10,1 12,7,15,14,12,1,12,12,2,14 24,1,9: - 12,23,26,26,5,21,5 22,11,15 - 16,15,3 1,7,5,1 15,13,24,11,11 23,21,2 17,20,12,1,21,18=
img2.02: =17,21,6,15 10,13,22,26,1,10,2,3 - 16,7,11,1 23,25,2,15,23,10,10,3 - 2?,11?,1,23 [key -1] 4,22,19,26,18,17 1,5,14,13,9,12,23,1,7,23,20 7,2 20,13,22,11,17 2,22,16 2,14,23
img2.03: 8,22,12,15 2,7,21,8,5,13 [del 2,7,21,8,5,13] 7,6,26 21,13,2,14,1,10,14 3,20,25,23 26,12,13,9,15,6,15 20,3.Decryption
img1.A.01 below the black line is copy of my last by the schooner
img1.A.02 wolf capt jones to sail about the eighteenth you will hear again
img1.A.03 keep up your spirits my plans are not changed yet at
img1.A.04 baltimore incog the tenth february business now
img1.A.05 detainsme wemust submit submit submit to ten days more of suspense the
img1.A.06 promise in[?] my last was rashly made affairs begin to
img1.A.07 lookup j'y travaille what would gamp not give to know that
img1.A.08 you are all well
img1.B.01 my last letter was written eight days ago poor gamp is
img1.B.02 still at baltimore on this blessed thirty first day of
img1.B.03 january still hoping and still persisting in all the plans so
img1.B.04 often written to you it distresses me to think that the
img1.B.05 hope of seeing me keeps you at the oaks at the hazard of your
img1.B.06 life indeed my be[s]t endeavors are used and shall be used
img1.B.07 to get to you if after ten days further delay it be found
img1.B.08 impracticable aperson shall be sent express to you and for
img1.B.09 you just four hours work huzzey
img1.C.01 no person must suspect that i mean to visit you in sc let it
img1.C.02 be believed except by mari that i am in philadelphia
img2.01 baltimore eighteenth feb nothing new the same hopes and
img2.02 intentions continue have[?] patience {2,11,1,23} hourly expectation of money for the
img2.03 long voyage and nothing else detains[?] me
numbers: 973; giving sense: 969 (99.6%)
emended or annotated words:
img1.A 15,16: in (emend: 15,16 gives "ix"; the key needs 15,6 (Burr wrote 16 for 6, or a misreading))
img1.A 18,5: j'y (Burr writes 18,5 = "jy" (French: j’y travaille))
img1.B 10,11,_,16: be[s]t (Burr left out the s: 10,11,16 = b,e,t with the key moved on)
img1.B 15,5,12,2,25,11,26,1,25,8,26,20,11: impracticable (torn: 4th number torn at the edge after its 2; the key needs 25 for r, so 2[5])
img1.B 4,23,2: for (torn: last number torn at the edge after its 2; the key needs 24 for r, so 2[4])
img2 16,7,11,1: have (emend: 11 gives "hase"; the key needs 14 for v (11/14 misread or Burr’s slip))
img2 2,11,1,23: - (unread: middle number rubbed on a fold; the key falls back one place after it)
img2 26,12,13,9,15,6,15: detains (emend: 13 gives "deoains"; the key needs 18 for t (13/18 misread or Burr’s slip))Reading
# Burr to Theodosia Burr Alston, Baltimore, January-February [1808]: reading of the number cipher
Deciphered with the key in `key.txt` (period-6 Vigenère, a=1 ... z=26, shifts 6 18 22 7 24 8). Line-by-line
decipherment against the cipher: `reading_numbers.txt` (`python decrypt.py --measure`). Punctuation and capitals
added here; Burr writes none in the cipher. [?] marks a word read against one number that disagrees with the key;
[s] a letter Burr left out; {..} the unread group.
## 1. Baltimore, 10 February [1808] (img1, above the first ruled line)
Below the black line is copy of my last, by the schooner Wolf, Capt. Jones, to sail about the eighteenth. You will
hear again. Keep up your spirits. My plans are not changed. Yet at Baltimore incog., the tenth February. Business now
detains me. We must submit, submit, submit to ten days more of suspense. The promise in[?] my last was rashly made.
Affairs begin to look up. J'y travaille. What would Gamp not give to know that you are all well.
## 2. Copy of the letter of 31 January [1808] (img1, between and below the ruled lines)
My last letter was written eight days ago. Poor Gamp is still at Baltimore on this blessed thirty-first day of
January, still hoping and still persisting in all the plans so often written to you. It distresses me to think that
the hope of seeing me keeps you at the Oaks at the hazard of your life. Indeed my be[s]t endeavors are used and shall
be used to get to you. If after ten days further delay it be found impracticable, a person shall be sent express to
you, and for you just four hours work, huzzey.
No person must suspect that I mean to visit you in S.C. Let it be believed, except by mari, that I am in
Philadelphia.
## 3. Baltimore, 18 February [1808] (img2)
Baltimore, eighteenth Feb. Nothing new. The same hopes and intentions continue. Have[?] patience. {2?,11?,1,23}
hourly expectation of money for the long voyage, and nothing else detains[?] me.
---
Notes: "Gamp" is Burr himself. "J'y travaille": French, "I am working at it". "Huzzey": as written, hussy (a pet
name). "Mari": as written, French for husband (Joseph Alston). The Oaks: the Alston plantation on the Waccamaw, S.C.
Measured: 973 cipher numbers, 969 read as sense (99.6%); the open group is rubbed on a fold.Baltimore, 10 February [1808] (img1, section A)
A cover note sending the copy of 31 January by the schooner Wolf: still at Baltimore incognito, business detains him ten days more, the promise in his last letter was rashly made, affairs begin to look up.
Transcription
# GLC01523, Aaron Burr to Joseph Alston. Transcription of the number cipher (Claude, 5 Nov 2026)
# Images: hamilton.gilderlehrman.org/sites/default/files/2023-10/GLC01523_Page_{1,2,3}.png
# img1 = GLC01523_Page_1.png (full page of number cipher, three sections divided by ruled lines)
# img2 = GLC01523_Page_2.png (three lines of number cipher at the head of a sheet)
# img3 = GLC01523_Page_3.png (clear page with the stroke cipher; see tally.txt)
# One token per number, numbers of a word joined by commas (Burr writes commas or dots), words separated by spaces.
# "=" at a line end / start: word runs on to the next line. "?" after a number: reading unsure.
# [ins N] = number written above the line with a caret (read as part of the word); [above N] = number written above
# with no caret (not part of the cipher; left out); [del ...] = struck through; [x] = an x-mark in the text.
# [om] = Burr left out a letter but the key moved on (B.06 "be[s]t"); [key -1] = the key falls back one place
# after an unread group (img2.02), from the phase of the words that follow.
# "-" = Burr's dash (a hooked stroke). Section breaks are the ruled lines on img1.
#
# --- img1, section A (above the first ruled line) ---
img1.A.01: 8,23,8,22,21 2,14?,23 24,19,25,11,17 4,5,21,3 17,25 21,11,23,23 23,12 5,21 19,25,1,26 - 20,21 1,6,13 25,21,4,22,13,22,11,10 19=
img1.A.02: =[ins 22],10,14 9,19,12,1: 8,23,20,23,15 ( 1,13 1,7,1,8 8,26,23,[ins 1],12 16,15,3 13,15,25,4,1,3,13,20,12,4 ) 6,13,3 3,1,8,19 6,13,7,10 23,14,25,17,20 -
img1.A.03: 3,1,12,14 3,22 17,11,2,16 1,22,1,14,16,18,1 - 19,17 12,19,25,22,25 19,14,12 12,23,26 21,4,8,12,15,11,22 - 21,12,18 9,26 20=
img1.A.04: =23,19,18,17,19,7,14,12 7,22,9,7,3: 1,6,13 26,23,10,1,6 14,11,20,14,2,25,26,5 - 20,17,26,7,22,11,11,15 21,13,5 10,23,16,8,7,22,25=
img1.A.05: =5,1 - 4,3,21,1,11,16 26,19,10,19,1,16 26,19,10,19,1,16 26,19,10,19,1,16 1,13 2,11,6 26,8,23,1 19,7,14,12 13,14 25,13,15,23,3,22,25,23 - 16,15,3
img1.A.06: 24,24,7,9,16,17,13 15,16 9,6 10,9,25,12 19,8,17 26,7,11,4,19,23 21,7,22,1 - [x] 8,[above 4]4,14,[above 6]7,1,14,26 26,13,13,1,10 1,13 20,21,7,7=
img1.A.07: =2,14 - 18?,5 12,14,8,20,9,15,4,8,12 - [above 5]21,16,7,12 19,22,19,20,10 25,23,20,14 22,21,12 3,16,20,13 26,7 7,21,13,5 26,26,23,1 23,23=
img1.A.08: =1 19,14,12 25,20,18 15,1,19,10 -
# --- img1, section B (between the ruled lines) ---
img1.B.01: 19,17 8,8,17,2 18,23,16,1,3,26 3,19,15 4,16,17,26,12,1,21 3,17,13,26,16 11,25,7,25 19,3,22 - 14,23,21,10 3,8,11,24 15,11 15,1=
img1.B.02: =7,20,18 19,16 9,25,20,26,1,9,22,16,13 21,6 16,15,7,1 8,4,1,26,17,13,10 12,4,16,16,2,5 24,5,25,17,2 10,19,21 22,4 18,7,6,17=
img1.B.03: =8,16,7 - 25,12,5,19,10 16,21,8,5,21,5 9,20,22 15,1,7,20,18 8,1,25,17,17,25,12,5,21,5 17,20 19,8,19 18,16,11 8,8,8,12,1 25,7
img1.B.04: 11,13,18,13,20 15,14,16,18,2,11,6 16,22 23,23,1 - 1,16 11,7,1,26,10,1,26,17,13,25 5,1 1,13 2,14,1,10,18 18,16,7,12 16,15,3 16=
img1.B.05: =21,8,1 22,4 1,11,23,5,21,5 21,11 3,1,12,14,1 5,7,17 8,18 2,14,23 11,8,9,1 7,12 16,15,3 16,7,18,23,25,2 23,12 17,11,2,16
img1.B.06: 20,15,24,1 - 16,12,12,11,23,26 20,23 10,11,[om],16 12,12,12,11,19,18,22,16,1 7,10,1 2,17,13,10 19,10,11 17,16,7,4,8 9,3 3,25,23,26
img1.B.07: 1,13 15,11,12 16,22 23,23,1 - 1,2 8,4,2,11,10 16,12,12 12,7,17,15 13,19,26,26,26,1,25 2,13,18,19,21 16,18 10,11 24,11,2,12,12 15,5,12,2?=
img1.B.08: =25,11,26,1,25,8,26,20,11 19,12,12,16,1,21,6 15,15,25,20,18 20,1 26,3,22,26 23,20,23,16,13,25,11 16,22 23,23,1 19,10,11 4,23,2?
img1.B.09: 17,11,2 - 8,3,25,12 2,22,19,26 14,7,17,25,17 5,21,10,7 15,19,8,6,23,21 -
# --- img1, section C (below the second ruled line) ---
img1.C.01: 20,7 12,12,16,1,21,6 9,2,17,2 25,13,15,23,[ins 3],11,26 12,4,8,18 17 19,23,23,21 18,23 2,1,15,16,18 7,21,13 5,21 17:11 - 18,23,16, 16,18
img1.C.02: 10,11 20,1,19,7,13,2,23,26 12,22,11,11,8,16 9,23 21,7,10,5 1,6,9,26 1? 23,20 7,22 22,26,5,19,25,12,11,4,12,15,7,9 -
# --- img2 ---
img2.01: 8,19,8,1,7,21,21,10,1 12,7,15,14,12,1,12,12,2,14 24,1,9: - 12,23,26,26,5,21,5 22,11,15 - 16,15,3 1,7,5,1 15,13,24,11,11 23,21,2 17,20,12,1,21,18=
img2.02: =17,21,6,15 10,13,22,26,1,10,2,3 - 16,7,11,1 23,25,2,15,23,10,10,3 - 2?,11?,1,23 [key -1] 4,22,19,26,18,17 1,5,14,13,9,12,23,1,7,23,20 7,2 20,13,22,11,17 2,22,16 2,14,23
img2.03: 8,22,12,15 2,7,21,8,5,13 [del 2,7,21,8,5,13] 7,6,26 21,13,2,14,1,10,14 3,20,25,23 26,12,13,9,15,6,15 20,3.Decryption
img1.A.01 below the black line is copy of my last by the schooner
img1.A.02 wolf capt jones to sail about the eighteenth you will hear again
img1.A.03 keep up your spirits my plans are not changed yet at
img1.A.04 baltimore incog the tenth february business now
img1.A.05 detainsme wemust submit submit submit to ten days more of suspense the
img1.A.06 promise in[?] my last was rashly made affairs begin to
img1.A.07 lookup j'y travaille what would gamp not give to know that
img1.A.08 you are all well
img1.B.01 my last letter was written eight days ago poor gamp is
img1.B.02 still at baltimore on this blessed thirty first day of
img1.B.03 january still hoping and still persisting in all the plans so
img1.B.04 often written to you it distresses me to think that the
img1.B.05 hope of seeing me keeps you at the oaks at the hazard of your
img1.B.06 life indeed my be[s]t endeavors are used and shall be used
img1.B.07 to get to you if after ten days further delay it be found
img1.B.08 impracticable aperson shall be sent express to you and for
img1.B.09 you just four hours work huzzey
img1.C.01 no person must suspect that i mean to visit you in sc let it
img1.C.02 be believed except by mari that i am in philadelphia
img2.01 baltimore eighteenth feb nothing new the same hopes and
img2.02 intentions continue have[?] patience {2,11,1,23} hourly expectation of money for the
img2.03 long voyage and nothing else detains[?] me
numbers: 973; giving sense: 969 (99.6%)
emended or annotated words:
img1.A 15,16: in (emend: 15,16 gives "ix"; the key needs 15,6 (Burr wrote 16 for 6, or a misreading))
img1.A 18,5: j'y (Burr writes 18,5 = "jy" (French: j’y travaille))
img1.B 10,11,_,16: be[s]t (Burr left out the s: 10,11,16 = b,e,t with the key moved on)
img1.B 15,5,12,2,25,11,26,1,25,8,26,20,11: impracticable (torn: 4th number torn at the edge after its 2; the key needs 25 for r, so 2[5])
img1.B 4,23,2: for (torn: last number torn at the edge after its 2; the key needs 24 for r, so 2[4])
img2 16,7,11,1: have (emend: 11 gives "hase"; the key needs 14 for v (11/14 misread or Burr’s slip))
img2 2,11,1,23: - (unread: middle number rubbed on a fold; the key falls back one place after it)
img2 26,12,13,9,15,6,15: detains (emend: 13 gives "deoains"; the key needs 18 for t (13/18 misread or Burr’s slip))Reading
# Burr to Theodosia Burr Alston, Baltimore, January-February [1808]: reading of the number cipher
Deciphered with the key in `key.txt` (period-6 Vigenère, a=1 ... z=26, shifts 6 18 22 7 24 8). Line-by-line
decipherment against the cipher: `reading_numbers.txt` (`python decrypt.py --measure`). Punctuation and capitals
added here; Burr writes none in the cipher. [?] marks a word read against one number that disagrees with the key;
[s] a letter Burr left out; {..} the unread group.
## 1. Baltimore, 10 February [1808] (img1, above the first ruled line)
Below the black line is copy of my last, by the schooner Wolf, Capt. Jones, to sail about the eighteenth. You will
hear again. Keep up your spirits. My plans are not changed. Yet at Baltimore incog., the tenth February. Business now
detains me. We must submit, submit, submit to ten days more of suspense. The promise in[?] my last was rashly made.
Affairs begin to look up. J'y travaille. What would Gamp not give to know that you are all well.
## 2. Copy of the letter of 31 January [1808] (img1, between and below the ruled lines)
My last letter was written eight days ago. Poor Gamp is still at Baltimore on this blessed thirty-first day of
January, still hoping and still persisting in all the plans so often written to you. It distresses me to think that
the hope of seeing me keeps you at the Oaks at the hazard of your life. Indeed my be[s]t endeavors are used and shall
be used to get to you. If after ten days further delay it be found impracticable, a person shall be sent express to
you, and for you just four hours work, huzzey.
No person must suspect that I mean to visit you in S.C. Let it be believed, except by mari, that I am in
Philadelphia.
## 3. Baltimore, 18 February [1808] (img2)
Baltimore, eighteenth Feb. Nothing new. The same hopes and intentions continue. Have[?] patience. {2?,11?,1,23}
hourly expectation of money for the long voyage, and nothing else detains[?] me.
---
Notes: "Gamp" is Burr himself. "J'y travaille": French, "I am working at it". "Huzzey": as written, hussy (a pet
name). "Mari": as written, French for husband (Joseph Alston). The Oaks: the Alston plantation on the Waccamaw, S.C.
Measured: 973 cipher numbers, 969 read as sense (99.6%); the open group is rubbed on a fold.Baltimore, 18 February [1808] (img2)
Nothing new: the same hopes and intentions; he waits hourly for money for 'the long voyage' (he sailed for England in June 1808), and nothing else keeps him.
Transcription
# GLC01523, Aaron Burr to Joseph Alston. Transcription of the number cipher (Claude, 5 Nov 2026)
# Images: hamilton.gilderlehrman.org/sites/default/files/2023-10/GLC01523_Page_{1,2,3}.png
# img1 = GLC01523_Page_1.png (full page of number cipher, three sections divided by ruled lines)
# img2 = GLC01523_Page_2.png (three lines of number cipher at the head of a sheet)
# img3 = GLC01523_Page_3.png (clear page with the stroke cipher; see tally.txt)
# One token per number, numbers of a word joined by commas (Burr writes commas or dots), words separated by spaces.
# "=" at a line end / start: word runs on to the next line. "?" after a number: reading unsure.
# [ins N] = number written above the line with a caret (read as part of the word); [above N] = number written above
# with no caret (not part of the cipher; left out); [del ...] = struck through; [x] = an x-mark in the text.
# [om] = Burr left out a letter but the key moved on (B.06 "be[s]t"); [key -1] = the key falls back one place
# after an unread group (img2.02), from the phase of the words that follow.
# "-" = Burr's dash (a hooked stroke). Section breaks are the ruled lines on img1.
#
# --- img1, section A (above the first ruled line) ---
img1.A.01: 8,23,8,22,21 2,14?,23 24,19,25,11,17 4,5,21,3 17,25 21,11,23,23 23,12 5,21 19,25,1,26 - 20,21 1,6,13 25,21,4,22,13,22,11,10 19=
img1.A.02: =[ins 22],10,14 9,19,12,1: 8,23,20,23,15 ( 1,13 1,7,1,8 8,26,23,[ins 1],12 16,15,3 13,15,25,4,1,3,13,20,12,4 ) 6,13,3 3,1,8,19 6,13,7,10 23,14,25,17,20 -
img1.A.03: 3,1,12,14 3,22 17,11,2,16 1,22,1,14,16,18,1 - 19,17 12,19,25,22,25 19,14,12 12,23,26 21,4,8,12,15,11,22 - 21,12,18 9,26 20=
img1.A.04: =23,19,18,17,19,7,14,12 7,22,9,7,3: 1,6,13 26,23,10,1,6 14,11,20,14,2,25,26,5 - 20,17,26,7,22,11,11,15 21,13,5 10,23,16,8,7,22,25=
img1.A.05: =5,1 - 4,3,21,1,11,16 26,19,10,19,1,16 26,19,10,19,1,16 26,19,10,19,1,16 1,13 2,11,6 26,8,23,1 19,7,14,12 13,14 25,13,15,23,3,22,25,23 - 16,15,3
img1.A.06: 24,24,7,9,16,17,13 15,16 9,6 10,9,25,12 19,8,17 26,7,11,4,19,23 21,7,22,1 - [x] 8,[above 4]4,14,[above 6]7,1,14,26 26,13,13,1,10 1,13 20,21,7,7=
img1.A.07: =2,14 - 18?,5 12,14,8,20,9,15,4,8,12 - [above 5]21,16,7,12 19,22,19,20,10 25,23,20,14 22,21,12 3,16,20,13 26,7 7,21,13,5 26,26,23,1 23,23=
img1.A.08: =1 19,14,12 25,20,18 15,1,19,10 -
# --- img1, section B (between the ruled lines) ---
img1.B.01: 19,17 8,8,17,2 18,23,16,1,3,26 3,19,15 4,16,17,26,12,1,21 3,17,13,26,16 11,25,7,25 19,3,22 - 14,23,21,10 3,8,11,24 15,11 15,1=
img1.B.02: =7,20,18 19,16 9,25,20,26,1,9,22,16,13 21,6 16,15,7,1 8,4,1,26,17,13,10 12,4,16,16,2,5 24,5,25,17,2 10,19,21 22,4 18,7,6,17=
img1.B.03: =8,16,7 - 25,12,5,19,10 16,21,8,5,21,5 9,20,22 15,1,7,20,18 8,1,25,17,17,25,12,5,21,5 17,20 19,8,19 18,16,11 8,8,8,12,1 25,7
img1.B.04: 11,13,18,13,20 15,14,16,18,2,11,6 16,22 23,23,1 - 1,16 11,7,1,26,10,1,26,17,13,25 5,1 1,13 2,14,1,10,18 18,16,7,12 16,15,3 16=
img1.B.05: =21,8,1 22,4 1,11,23,5,21,5 21,11 3,1,12,14,1 5,7,17 8,18 2,14,23 11,8,9,1 7,12 16,15,3 16,7,18,23,25,2 23,12 17,11,2,16
img1.B.06: 20,15,24,1 - 16,12,12,11,23,26 20,23 10,11,[om],16 12,12,12,11,19,18,22,16,1 7,10,1 2,17,13,10 19,10,11 17,16,7,4,8 9,3 3,25,23,26
img1.B.07: 1,13 15,11,12 16,22 23,23,1 - 1,2 8,4,2,11,10 16,12,12 12,7,17,15 13,19,26,26,26,1,25 2,13,18,19,21 16,18 10,11 24,11,2,12,12 15,5,12,2?=
img1.B.08: =25,11,26,1,25,8,26,20,11 19,12,12,16,1,21,6 15,15,25,20,18 20,1 26,3,22,26 23,20,23,16,13,25,11 16,22 23,23,1 19,10,11 4,23,2?
img1.B.09: 17,11,2 - 8,3,25,12 2,22,19,26 14,7,17,25,17 5,21,10,7 15,19,8,6,23,21 -
# --- img1, section C (below the second ruled line) ---
img1.C.01: 20,7 12,12,16,1,21,6 9,2,17,2 25,13,15,23,[ins 3],11,26 12,4,8,18 17 19,23,23,21 18,23 2,1,15,16,18 7,21,13 5,21 17:11 - 18,23,16, 16,18
img1.C.02: 10,11 20,1,19,7,13,2,23,26 12,22,11,11,8,16 9,23 21,7,10,5 1,6,9,26 1? 23,20 7,22 22,26,5,19,25,12,11,4,12,15,7,9 -
# --- img2 ---
img2.01: 8,19,8,1,7,21,21,10,1 12,7,15,14,12,1,12,12,2,14 24,1,9: - 12,23,26,26,5,21,5 22,11,15 - 16,15,3 1,7,5,1 15,13,24,11,11 23,21,2 17,20,12,1,21,18=
img2.02: =17,21,6,15 10,13,22,26,1,10,2,3 - 16,7,11,1 23,25,2,15,23,10,10,3 - 2?,11?,1,23 [key -1] 4,22,19,26,18,17 1,5,14,13,9,12,23,1,7,23,20 7,2 20,13,22,11,17 2,22,16 2,14,23
img2.03: 8,22,12,15 2,7,21,8,5,13 [del 2,7,21,8,5,13] 7,6,26 21,13,2,14,1,10,14 3,20,25,23 26,12,13,9,15,6,15 20,3.Decryption
img1.A.01 below the black line is copy of my last by the schooner
img1.A.02 wolf capt jones to sail about the eighteenth you will hear again
img1.A.03 keep up your spirits my plans are not changed yet at
img1.A.04 baltimore incog the tenth february business now
img1.A.05 detainsme wemust submit submit submit to ten days more of suspense the
img1.A.06 promise in[?] my last was rashly made affairs begin to
img1.A.07 lookup j'y travaille what would gamp not give to know that
img1.A.08 you are all well
img1.B.01 my last letter was written eight days ago poor gamp is
img1.B.02 still at baltimore on this blessed thirty first day of
img1.B.03 january still hoping and still persisting in all the plans so
img1.B.04 often written to you it distresses me to think that the
img1.B.05 hope of seeing me keeps you at the oaks at the hazard of your
img1.B.06 life indeed my be[s]t endeavors are used and shall be used
img1.B.07 to get to you if after ten days further delay it be found
img1.B.08 impracticable aperson shall be sent express to you and for
img1.B.09 you just four hours work huzzey
img1.C.01 no person must suspect that i mean to visit you in sc let it
img1.C.02 be believed except by mari that i am in philadelphia
img2.01 baltimore eighteenth feb nothing new the same hopes and
img2.02 intentions continue have[?] patience {2,11,1,23} hourly expectation of money for the
img2.03 long voyage and nothing else detains[?] me
numbers: 973; giving sense: 969 (99.6%)
emended or annotated words:
img1.A 15,16: in (emend: 15,16 gives "ix"; the key needs 15,6 (Burr wrote 16 for 6, or a misreading))
img1.A 18,5: j'y (Burr writes 18,5 = "jy" (French: j’y travaille))
img1.B 10,11,_,16: be[s]t (Burr left out the s: 10,11,16 = b,e,t with the key moved on)
img1.B 15,5,12,2,25,11,26,1,25,8,26,20,11: impracticable (torn: 4th number torn at the edge after its 2; the key needs 25 for r, so 2[5])
img1.B 4,23,2: for (torn: last number torn at the edge after its 2; the key needs 24 for r, so 2[4])
img2 16,7,11,1: have (emend: 11 gives "hase"; the key needs 14 for v (11/14 misread or Burr’s slip))
img2 2,11,1,23: - (unread: middle number rubbed on a fold; the key falls back one place after it)
img2 26,12,13,9,15,6,15: detains (emend: 13 gives "deoains"; the key needs 18 for t (13/18 misread or Burr’s slip))Reading
# Burr to Theodosia Burr Alston, Baltimore, January-February [1808]: reading of the number cipher
Deciphered with the key in `key.txt` (period-6 Vigenère, a=1 ... z=26, shifts 6 18 22 7 24 8). Line-by-line
decipherment against the cipher: `reading_numbers.txt` (`python decrypt.py --measure`). Punctuation and capitals
added here; Burr writes none in the cipher. [?] marks a word read against one number that disagrees with the key;
[s] a letter Burr left out; {..} the unread group.
## 1. Baltimore, 10 February [1808] (img1, above the first ruled line)
Below the black line is copy of my last, by the schooner Wolf, Capt. Jones, to sail about the eighteenth. You will
hear again. Keep up your spirits. My plans are not changed. Yet at Baltimore incog., the tenth February. Business now
detains me. We must submit, submit, submit to ten days more of suspense. The promise in[?] my last was rashly made.
Affairs begin to look up. J'y travaille. What would Gamp not give to know that you are all well.
## 2. Copy of the letter of 31 January [1808] (img1, between and below the ruled lines)
My last letter was written eight days ago. Poor Gamp is still at Baltimore on this blessed thirty-first day of
January, still hoping and still persisting in all the plans so often written to you. It distresses me to think that
the hope of seeing me keeps you at the Oaks at the hazard of your life. Indeed my be[s]t endeavors are used and shall
be used to get to you. If after ten days further delay it be found impracticable, a person shall be sent express to
you, and for you just four hours work, huzzey.
No person must suspect that I mean to visit you in S.C. Let it be believed, except by mari, that I am in
Philadelphia.
## 3. Baltimore, 18 February [1808] (img2)
Baltimore, eighteenth Feb. Nothing new. The same hopes and intentions continue. Have[?] patience. {2?,11?,1,23}
hourly expectation of money for the long voyage, and nothing else detains[?] me.
---
Notes: "Gamp" is Burr himself. "J'y travaille": French, "I am working at it". "Huzzey": as written, hussy (a pet
name). "Mari": as written, French for husband (Joseph Alston). The Oaks: the Alston plantation on the Waccamaw, S.C.
Measured: 973 cipher numbers, 969 read as sense (99.6%); the open group is rubbed on a fold.Key: key.txt
06 Sources
- Gilder Lehrman Collection, GLC01523: catalogue record; page images on the Hamilton Education Program page.
- Matthew L. Davis, Memoirs of Aaron Burr (1837): no letters between October 1807 and June 1808; the 18 July 1804 letter used for the control (Project Gutenberg).
- Mary-Jo Kline and Joanne Wood Ryan, eds., Political Correspondence and Public Papers of Aaron Burr (Princeton, 1983): table of contents only (Internet Archive, lending copy).
- The July 1804 letter these sheets were filed with: Burr to Joseph Alston, July 1804.
Working files: targets/burr1808/ (transcription, decoder, key, reading, control, notes, work log).
Cite this page
Daniel Bourdeau, “Aaron Burr to Theodosia, Baltimore, January–February 1808”, Cyphersolver, posted 5 November 2026, updated 7 November 2026, https://cyphersolver.com/burr1808.html.