{
  "generated": "2026-09-02",
  "scope": "Nephos currently has three built public records plus one audited ten-leaf Turner shorthand; this is not a corpus-scale test.",
  "cases": [
    {
      "id": "yale-howard-retranscription",
      "object": {
        "museum": "Yale Center for British Art",
        "accession": "B1981.25.116",
        "title": "Cloud Study",
        "date": "21 September 1822"
      },
      "claim": "Nephos first read Howard's wind for the 21st as NE by machine text recognition (OCR) and counted it as agreeing with Constable's East. The reading was marked to be checked against the page image before it could be cited.",
      "pushback": "The first NE reading was made by machine text recognition (OCR) and was not ready to be cited. Direct inspection on 18 August 2026 established that Howard's register reads NE, not E; it is also from a different London location than the assumed Hampstead site.",
      "verdict": "Partially agrees",
      "what_changed": "Direct inspection established the transcription, while source distance and the non-identical directions kept the comparison at partial agreement.",
      "sources": [
        {
          "label": "Nephos machine record from before the page check, with its OCR caveat",
          "url": "/data/constable-analysis-pre-verification-6ae6c62.json"
        },
        {
          "label": "Verified Nephos machine record",
          "url": "/data/constable-analysis.json"
        },
        {
          "label": "Howard September 1822 page image",
          "url": "https://archive.org/download/in.ernet.dli.2015.48048/page/n96.jpg"
        },
        {
          "label": "Yale Nephos record",
          "url": "/record/ycba/b1981-25-116/"
        }
      ],
      "record_url": "/record/ycba/b1981-25-116/"
    },
    {
      "id": "yale-cloud-amount-comparison",
      "object": {
        "museum": "Yale Center for British Art",
        "accession": "B1981.25.116",
        "title": "Cloud Study",
        "date": "21 September 1822"
      },
      "claim": "The Yale capture segmentation measured 58% opaque cloud while the 20th Century Reanalysis ensemble mean was 61% cloud, with ±33 percentage points of ensemble spread, over the London-area grid cell.",
      "pushback": "The 61% ensemble mean carries +/-33 percentage points of spread over a regional 1-degree grid cell, while 58% is a capture-specific paint segmentation rather than an atmospheric observation.",
      "verdict": "Partially agrees",
      "what_changed": "The three-point difference is treated as compatible within wide uncertainty, not as a match.",
      "sources": [
        {
          "label": "Verified Nephos machine record",
          "url": "/data/constable-analysis.json"
        },
        {
          "label": "NOAA 20th Century Reanalysis v3",
          "url": "https://www.psl.noaa.gov/data/gridded/data.20thC_ReanV3.html"
        },
        {
          "label": "Yale Nephos record",
          "url": "/record/ycba/b1981-25-116/"
        }
      ],
      "record_url": "/record/ycba/b1981-25-116/"
    },
    {
      "id": "constable-same-day-pair",
      "object": {
        "museum": "Yale Center for British Art and Courtauld Gallery",
        "accession": "B1981.25.116 and P.1952.RW.69",
        "title": "Cloud Study pair",
        "date": "21 September 1822"
      },
      "claim": "Constable's Yale note at about 13:30 and Courtauld note at 15:00 give the same date, a southward view, an easterly wind, and warmth.",
      "pushback": "Both notes are by Constable, so their agreement is internal consistency rather than evidence from another observer. Howard records NE and the regional model gives ENE rather than E; the shared date, view, and warmth remain unverified by the comparison, and no visual cloud comparison was performed.",
      "verdict": "Partially agrees",
      "what_changed": "The same-day pair is treated as internal consistency within one artist's notes plus partial agreement with external wind evidence.",
      "sources": [
        {
          "label": "Yale Nephos record",
          "url": "/record/ycba/b1981-25-116/"
        },
        {
          "label": "Courtauld object record",
          "url": "https://gallerycollections.courtauld.ac.uk/object-p-1952-rw-69"
        },
        {
          "label": "Courtauld Nephos record",
          "url": "/record/courtauld/p-1952-rw-69/"
        },
        {
          "label": "Verified Nephos machine record",
          "url": "/data/constable-analysis.json"
        },
        {
          "label": "Howard September 1822 page image",
          "url": "https://archive.org/download/in.ernet.dli.2015.48048/page/n96.jpg"
        }
      ],
      "record_url": "/record/courtauld/p-1952-rw-69/"
    },
    {
      "id": "ashmolean-impossible-date",
      "object": {
        "museum": "Ashmolean Museum",
        "accession": "WA1933.7",
        "title": "Study of Clouds",
        "date": "1822; inscription says 31 September, catalogue corrects to 1 October"
      },
      "claim": "The inscription reads 31 September 1822, and the Ashmolean catalogue identifies the date as Constable's mistake and corrects it to 1 October 1822.",
      "pushback": "The literal date is impossible. Howard records conditions compatible with the inscription on both 30 September and 1 October, so the weather evidence cannot decide which neighbouring day was intended.",
      "verdict": "Contradicts",
      "what_changed": "The literal date is contradicted, while the catalogue's 1 October correction remains plausible but unproved by weather.",
      "sources": [
        {
          "label": "Ashmolean collections API",
          "url": "https://prd-online.glamdigital.io/v2/item/ash-object-372592/full"
        },
        {
          "label": "Howard September 1822 page image",
          "url": "https://archive.org/download/in.ernet.dli.2015.48048/page/n96.jpg"
        },
        {
          "label": "Howard October 1822 page image",
          "url": "https://archive.org/download/in.ernet.dli.2015.48048/page/n100.jpg"
        },
        {
          "label": "Ashmolean Nephos record",
          "url": "/record/ashmolean/wa1933-7/"
        }
      ],
      "record_url": "/record/ashmolean/wa1933-7/"
    },
    {
      "id": "turner-d12490-tambora",
      "object": {
        "museum": "Tate",
        "accession": "D12490; Turner Bequest CLVIII 42",
        "title": "Study of the Sun Rising or Setting over a Landscape",
        "date": "c.1818"
      },
      "claim": "Tate says the colours may reflect atmospheric conditions following the 1815 Tambora eruption.",
      "pushback": "D12490 visibly includes the solar disc, so it is inconsistent with the cited secondary-afterglow geometry, which occurs after the sun is below the horizon. This does not exclude broader volcanic-aerosol effects, but the sheet alone cannot establish a link to Tambora.",
      "verdict": "underdetermines",
      "what_changed": "The catalogue's may hedge is retained, and the audited shorthand rejects a stronger secondary-afterglow attribution for this leaf.",
      "sources": [
        {
          "label": "Tate research entry for D12490",
          "url": "https://www.tate.org.uk/art/research/content/1208914?project=1"
        },
        {
          "label": "von Savigny et al. 2024",
          "url": "https://acp.copernicus.org/articles/24/2415/2024/"
        },
        {
          "label": "Nephos, Turner Skies shorthand, 30 August 2026 (PDF), ten leaves from Tate's Skies sketchbook with sources; claims audited against the linked sources before release",
          "url": "/turner/turner-skies-shorthand-2026-08-30.pdf"
        }
      ],
      "record_url": null
    }
  ]
}