{
 "schema": "nephos.method.v1",
 "slug": "brown-castle-geyser-1891",
 "title": "Grafton Tyler Brown, Castle Geyser, Yellowstone (1891), Eiteljorg 2017.3.1",
 "urls": [
  "/studies/brown-castle-geyser-1891"
 ],
 "written": {
  "summary": "The Eiteljorg dates the on-site sketch to 6 September 1890 and completion to Brown’s Helena studio in 1891. These are two stages of making, not two competing dates.",
  "items": [
   {
    "quote": "on-site on September 6, 1890",
    "source": "Eiteljorg Museum, Artist Spotlight",
    "url": "https://eiteljorg.org/martin-luther-king-jr-day/?t=103"
   },
   {
    "quote": "at his Helena, Montana, studio",
    "source": "Eiteljorg Museum, Artist Spotlight",
    "url": "https://eiteljorg.org/martin-luther-king-jr-day/?t=103"
   }
  ]
 },
 "records": [
  {
   "name": "Mammoth Hot Springs Army register, September 1890",
   "detail": "All 30 daily thermometer maxima and minima, checked against the 1891 superintendent report. Two versions of one station record.",
   "url": "https://www.ncei.noaa.gov/nerms/api/document/69AEAFAE95E349CC8832AD6AC183377B/download"
  },
  {
   "name": "Superintendent report, printed pages 14–15",
   "detail": "The sketch-date row includes a snow remark; this is a record at Mammoth, not at the geyser.",
   "url": "https://archive.org/download/reportofsuperint1891unit/reportofsuperint1891unit.pdf"
  }
 ],
 "gaps": [
  "No local Castle Geyser thermometer, cloud or wind observation for the sketch session has been verified.",
  "The field sketch and original reverse were not inspected; no hour or eruption is tied to the painting.",
  "No painting-specific scholarly description found in this research establishes a meteorological reading of this canvas."
 ],
 "tests": [
  {
   "claim": "What happened at Mammoth on the sketch date?",
   "result": "On the documented sketch date, Mammoth recorded a high of 45 °F and a low of 28 °F, with snow covering the ground. Its high was the lowest of the 30 daily maxima that month. Weather at Castle Geyser and any change Brown made remain unknown."
  },
  {
   "claim": "Does the record prove that Brown changed the weather?",
   "result": "No. A later studio canvas and an observation in another part of the park cannot establish the weather of the scene or how it was altered."
  }
 ],
 "finding": "On the documented sketch date, Mammoth recorded a high of 45 °F and a low of 28 °F, with snow covering the ground. Its high was the lowest of the 30 daily maxima that month. Weather at Castle Geyser and any change Brown made remain unknown.",
 "verdicts": [
  {
   "claim": "Weather in the finished painting",
   "verdict": "Unknown",
   "reason": "A documented field date does not date every element of a later studio composition."
  },
  {
   "claim": "Snow at Castle Geyser during the sketch session",
   "verdict": "Unknown",
   "reason": "The surviving observation is at Mammoth; neither the local event nor the sketch hour is established."
  }
 ],
 "limits": [
  "Daily maxima and minima are labelled by the original date; the thermometer reset hour is not established.",
  "The rain amount has a different date alignment in the manuscript and printed report. It is excluded.",
  "The printed snow amount is marked inappreciable; it is not converted to zero or to a measured snow depth.",
  "The monthly comparison is not a climate ranking. No modern normal or regional average is used.",
  "One owner checked both sources. They are not independent witnesses, and no independent checker ran."
 ]
}