At a glanceNot solved · text not obtained
- The letters
- Arend Willem baron van Reede, the Orangist envoy in Berlin, to the Hereditary Prince Willem Frederik (1796–1807) and to Princess Wilhelmina (1797–1801), in French with runs of numbers; several are written over a letter in invisible ink.
- Where
- Koninklijk Huisarchief, The Hague, A35-1232 (scans 143592, 143603, 144339, 144352, 144361, 144448–49, 144507) and A32-549 (171667, 171744). Not on DECODE.
- The cipher
- In 1796 a “Chiffre Littéral” in which a short run of numbers stands for a whole sentence, with dotted groups such as 39.97.16: a book code keyed to a shared printed text, beside a short list of numbers for names. From 1797 a larger numbered list with prefixes and superscripts.
- How it was tried
- All nine passages and four glossed letters were transcribed at full size. Van Reede’s 1789–92 code and the Euler word list of 1795–96 were tested on the glossed runs; neither fits (3 of 13 and 3 of 32 decoded words in the run’s own gloss).
- Why it resists
- The book of the 1796 code is not named anywhere in the file, and the later list has only about fifteen glossed values.
01 The passages
The pairing of all 300 scans of A35-1232 and 139 of A32-549 (research files pairs_A35-1232.tsv, pairs_A32-549.tsv) left nine code passages with no decipherment:
| Image | Date | Groups | Note |
|---|---|---|---|
| 143592 | Jan–Feb 1796 | 78 in 14 runs | black letter over brown invisible ink |
| 143603 | Feb 1796 | 50 | rows of figures over an invisible-ink letter |
| 144339 | P.S., Jan 1796 | 54 | the “petit chiffre”; warns not to confuse “valeurs réelles” with “indicateurs” |
| 144352 | Blankenburg, 5 July 1796 | 19 | |
| 144361 | “Précis” of 29 July 1796 | 127 | sent in cipher because the letter was too long |
| 144448–49 | c. Dec 1801 | 73 | between lines of invisible ink |
| 144507 | c. 1806–07 | 35 | over invisible ink |
| 171667 | 1797–98 | about 98 | to Wilhelmina; fractions and plus signs |
| 171744 | Berlin, 5 Dec 1800 or 1801 | 46 | to Wilhelmina; “Votre chiffre primitif” |
02 Van Reede’s Explication
The letter of 15 August 1796 carries its own key. Its run (1.), seven groups, is explained as “envoyé à Ivoy un mémoire pour établir & justifier les principes d’une nouvelle coalition basant sur la reconnoissance de Louis XVIII comme seul moyen d’inspirer de la confiance à la Prusse”; run (3.) as “qu’il n’y avoit rien à faire dès que l’Angleterre n’adoptoit pas en plein la marche proposée”. Seven groups for some two hundred letters cannot be a letter cipher or a word code; with the dotted groups in the text (“39.97.16”, “29.17.19.37”) and Van Reede’s words, “Je me sers, Monseigneur, du Chiffre Littéral usité pour ma correspondance particulière avec Elle”, the system reads as a book code, each group pointing into a printed text that both men held. The text is not named in the file.
The Prince’s own drafts in the same folder (Berlin 11 June, 2 July 1796 and others) are the clear texts of letters he sent in cipher to Van Reede; the enciphered versions are not here.
03 What was tried
- Transcription. The nine passages and the glossed letters of 15 August 1796, 27 September 1796 (the Prince’s draft, meanings in parentheses), 19 May and October–November 1798 were transcribed at full size with every mark (
runs_a.txt,runs_b.txt). - Known keys.
test_keys.pydecoded every run with Van Reede’s 1789–92 code to Wilhelmina (targets/reede1789) and with the Euler word list of 1795–96 (targets/wilhelmina1795), and scored both on the fifteen glossed runs: 3 of 13 and 3 of 32 decoded words stand in the run’s own gloss, against 2 and 0 in another run’s. The glossed values contradict both (13 is Athlone here, “difficile” in the Euler list; 6/52 is Haugwitz in 1798, where the Euler list has 52 = une). - Print. Colenbrander’s Gedenkstukken II and III, searched in full text, print no letter of Van Reede to the Prince.
04 What remains open
- All nine passages, about 580 groups: unread for lack of key material. A reading of the 1796 passages needs the book; the Explication gives plaintext for one letter only, too little to identify a book by itself.
- The 1797–1801 list (groups to 1951) has about fifteen glossed values in the file.
05 Sources
- Koninklijk Huisarchief, The Hague, A35 Willem I, inv. A35-1232, letters of A.W. van Reede, 1788–1814; A32 Wilhelmina, inv. A32-549, letters of Van Reede, 1796–1814; on Koninklijke Verzamelingen.
- H.T. Colenbrander, Gedenkstukken der algemeene geschiedenis van Nederland van 1795 tot 1840, II–III (1906–07), full text on resources.huygens.knaw.nl.
- Related here: d’Yvoy and the Hereditary Prince, 1797–99, the Hereditary Prince from Berlin, 1796.
Files: targets/reede1796/ (transcriptions, key test, NOTES).