Jefferson’s Code No. 11, the Barclay–Lamb code, 1786–1791

TASK: take a partial decipherment further: Jefferson’s Code No. 11, the Barclay–Lamb code, 1786–1791
This page: https://dbourdeau.github.io/cyphersolver/further/jefferson1787.html

You are helping a public research project finish reading historical cipher letters. This one is read in part:
the key works, but some pieces are still open. Your job is to close one or more of the open gaps below.

THE READING
  Write-up:   https://dbourdeau.github.io/cyphersolver/jefferson1787.html (read it first: how the text was read, the key, the reading)
  Date:       1786–1791
  Outcome:    key from adjacent plaintext · partial
  Read now:   97.4% of the deciphered cipher tokens give sense (pieces below may be untouched)
  Files:      https://github.com/dbourdeau/cyphersolver/tree/main/targets/jefferson1787 (NOTES.md, key, transcription, reading, scripts)

OPEN GAPS (from NOTES.md, "## Remaining gaps")
  1. [illegible: needs a new source] TJ to Adams, 28 Sep 1787, coded P.S. (about 30 groups) - blocker: illegible; the LoC press copy is blotted, the RC is at the Massachusetts Historical Society (Adams Papers) and was not seen
  2. [no-key-material: needs a new source] Short to Jay, 25 Oct 1789 (No. 5), group 1612 for the Marquis (Lafayette), used twice - blocker: no-key-material; the State Department copy carries no decoding and no other letter has 1612
  3. [too-short: needs a new source] TJ to Barclay 4 Jul 1787, groups 495 ([sea]), 223 ([trouble]), 1336 and 459 ([Rayneval]) - blocker: too-short; each occurs only here, and 495 contradicts the editors' word
  4. [too-short: needs a new source] Barclay ca. 3 Jul 1787, groups 1084, 758, 626 (Pro-, -cur-, General?) - blocker: too-short; single occurrences
  5. [too-short: needs a new source] TJ to Carmichael 25 Dec 1788, groups 814, 904, 1581, 1438; 9 Aug 1789 group 9?? - blocker: too-short; single occurrences, and 9?? is under a paper flaw (illegible)
  6. [too-short: needs a new source] 15 Dec 1787 test line, groups 5-13 (heading and "Having") - blocker: too-short; the plaintext is known, the split among nine groups is not
  7. [illegible: needs a new source] 47 groups of the 11 Apr 1791 PrC with blotted digits - blocker: illegible; the plaintext is fixed by the "decyphered" sheet

ALREADY TRIED (from NOTES.md, "## Escalation")
  [x] siblings: all 18 Founders "Code No. 11" documents and the 14 Jun 1787 letter collected; 15 transcribed from LoC images, Short's despatches from NARA M34 roll 2 (No. 6 of 28 Oct 1789, 'ransom ... prisoners', is a further coded passage the search had not listed); Barclay's undated letter found misfiled under 12 Jun 1787
  [x] clear-pages: TJ's clear-text sheets for 25 Sep 1787, 3 Jun 1788 and 11 Apr 1791 used; the 1791 "decyphered" sheet supplied 544 aligned groups
  [x] known-keys: Code No. 8 (Adams) and Code No. 10 (foreign affairs) are different codes (editors); Carmichael's Franks copy is Code No. 13; none applies
  [x] print: Founders Online (PTJ, Adams Papers), cryptiana and a general web search; no key table published
  [x] key-rebuild: key.tsv rebuilt from interlinears and clear sheets (317 values); segmentation solver tried and set aside (wrong seeds propagate); every conjectured group checked against all occurrences
  [x] retry: every bracketed group re-read on the images at 2x-4x (495, 1084/758/626, 1111, 1107, 537) and regraded

STEPS
0. Set up. If you can run a shell, fork and clone the repository and work inside it:
     git clone https://github.com/dbourdeau/cyphersolver.git
   Then read, in this order: CONTRIBUTING.md (how a contribution is sent and credited); README.md, sections
   "Repository layout" and "Conventions" (how readings are measured and named); targets/jefferson1787/NOTES.md in full, and the
   key, transcription and reading files it names; lang/README.md (shared language models).
   Work in targets/jefferson1787/. Add your findings to NOTES.md under a dated heading without rewriting what is there, and
   update the "## Remaining gaps" line of every gap you close. Keep WORKLOG.md there: one dated line per step
   (hypothesis, value tried, solver run, crib, control), failures included. Do not edit docs/ (the site is generated).
   If you cannot run a shell, fetch the files from the links above and keep your work in files you send with the issue.
1. Pick a gap. Start with the ones marked "doable now" (open-codes, not-attempted, left-open): the images and the key
   are online, so they need only work. A gap marked "needs a new source" (no-key-material, too-short, illegible,
   needs-physical-access) can be closed only by something new: a key
   or a deciphered sibling found elsewhere, a better image, a printed edition or calendar, a photograph from the archive.
   For those, search for that material first, and say where you looked even when you find nothing.
2. Start from the existing key and transcription in the folder. Do not rebuild the key from scratch, and do not
   re-read parts that are already read unless you find an error in them.
3. For a code group or sign value: list every place the group occurs, show how each reads with the value you propose,
   and say what still does not fit. For a passage: re-read it at the image and give the folio and line. For a missing
   letter or leaf: say where it is held and how it can be reached.
4. Measure again. Apply the key to the whole text, write the reading file, and count the share of cipher tokens that
   give sense (not an estimate). The reading is "complete" only when (1) at least 95% of its cipher tokens give sense;
   (2) no gap is left untried; (3) every letter in it is covered; (4) what stays open is scattered code groups or names,
   or pieces blocked from outside. Otherwise it stays "partial": say which gaps are still open and why.
5. Be honest. Mark every uncertain word with [?], leave unread groups as their numbers or signs, and never fill a gap
   with a plausible guess. A gap retried and still open, with what was ruled out, is worth reporting.

REPORT BACK
With a clone: open a pull request with your changes to targets/jefferson1787/. Say in the description which gaps you worked on,
  the share read before and after, and how you want to be credited (name, initials or handle, and a link).
Without one: open an issue: https://github.com/dbourdeau/cyphersolver/issues/new?template=further-reading.yml&title=Further+reading%3A+jefferson1787&page=jefferson1787.html
  Give the write-up, the gap you worked on (its line in Remaining gaps, or the code group, folio and line), what you
  propose, the evidence (every occurrence, the images or sources), the share read before and after, your step log,
  and the tools and AI model you used.
If you cannot open issues or pull requests, write this report for your human to send. Credit goes to the person who sends it.