{
 "meta": {
  "dataset": "Khafre dimensional provenance",
  "version": "1.0",
  "extracted": "2026-08-17",
  "method": "Primary-source extraction: Petrie 1883 (two independent archive.org scans, cross-validated OCR), Vyse 1840 vol. II (values read from page images, not OCR), Maragioglio & Rinaldi 1966 (archive.org scan + saved plates). Legon GM 110 (1989): NOT OBTAINED - search trail in notes.",
  "legon": "NOT OBTAINED. Wayback 503 on all legon.demon.co.uk article pages; Harvard Digital Giza hosts six other Legon PDFs but not GM 110; academia.edu 403. Ten circulated decimals (34.94, 7.88, 6.71, 14.65, 9.69, 39.37, 41.86, 16.02, 2.58, 36.95) matched against Legon DE10/DE14 full texts: zero matches. NOTE: 6.71 m exactly matches Vyse vol.II p.119 'Inclined entrance to lower chamber, length' (22 ft 0 in).",
  "record_count": 246,
  "mr_lengths_finding": "CONFIRMED ABSENT (2026-08-17 deep pass): M&R Testo 5,1 gives NO total corridor lengths for L,O,G(full),A,P,I,R,X anywhere in text or Osservazioni. Only corridor D (~37 m, original floor) and an ~11 m stretch of G are stated. An independent M&R geometry model awaits the separate Tavole drawings volume (TAV.7-10, dimensioned plates).",
  "tavole_finding": "2026-08-17 Tavole pass: M&R plate drawings DO carry dimension chains. Independent M&R length skeleton recovered: D 31.70 m floor (vs Vyse 31.95 - agreement <1%; text's '37 m' = original incl. lost upper portion), G 39.35 m (vs Vyse 39.13 - <1%), P 15.75 m, I 34.15 m, O 18.32 m ceiling, L 8.07 m. A not isolated (projection only); X filled with masonry, no dims. Cross-survey test UNBLOCKED."
 },
 "records": [
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.33",
   "original_units": "inches",
   "metric_conversion_m": 1.202182,
   "feature": "Entrance passage height, E side, at mouth",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'At mouth'. Cross-validated identically in two independent OCR passes of two separate Internet Archive scans (cu31924012038927 and the-pyramids-and-temples-of-gizeh_202306).",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.32",
   "original_units": "inches",
   "metric_conversion_m": 1.201928,
   "feature": "Entrance passage height, W side, at mouth",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'At mouth'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.62",
   "original_units": "inches",
   "metric_conversion_m": 1.057148,
   "feature": "Entrance passage width, Top, at mouth",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'At mouth'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.21",
   "original_units": "inches",
   "metric_conversion_m": 1.046734,
   "feature": "Entrance passage width, Base, at mouth",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'At mouth'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.31",
   "original_units": "inches",
   "metric_conversion_m": 1.201674,
   "feature": "Entrance passage height, E side, half-way down",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Half-way down'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.13",
   "original_units": "inches",
   "metric_conversion_m": 1.197102,
   "feature": "Entrance passage height, W side, half-way down",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Half-way down'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.08",
   "original_units": "inches",
   "metric_conversion_m": 1.043432,
   "feature": "Entrance passage width, Top, half-way down",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Half-way down'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.17",
   "original_units": "inches",
   "metric_conversion_m": 1.045718,
   "feature": "Entrance passage width, Base, half-way down",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Half-way down'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.44",
   "original_units": "inches",
   "metric_conversion_m": 1.204976,
   "feature": "Entrance passage height, E side, near end",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Near end'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.23",
   "original_units": "inches",
   "metric_conversion_m": 1.199642,
   "feature": "Entrance passage height, W side, near end",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Near end'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.34",
   "original_units": "inches",
   "metric_conversion_m": 1.050036,
   "feature": "Entrance passage width, Top, near end",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Near end'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.33",
   "original_units": "inches",
   "metric_conversion_m": 1.049782,
   "feature": "Entrance passage width, Base, near end",
   "confidence": "HIGH",
   "notes": "Verbatim table row 'Near end'.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47.29 ± 0.03",
   "original_units": "inches",
   "metric_conversion_m": 1.201166,
   "feature": "Entrance passage mean height",
   "confidence": "HIGH",
   "notes": "Petrie's own stated mean of the three height readings, with probable error.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "41.29 ± 0.05",
   "original_units": "inches",
   "metric_conversion_m": 1.048766,
   "feature": "Entrance passage mean width",
   "confidence": "HIGH",
   "notes": "Petrie's own stated mean of the three width readings, with probable error.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "490.3",
   "original_units": "inches",
   "metric_conversion_m": 12.45362,
   "feature": "Entrance passage axis, offset E of middle of N face",
   "confidence": "MEDIUM",
   "notes": "'its axis is 490.3 E. of the middle of the N. face.' Digit grouping '490' + '3' confirmed identically in both independent OCR passes, so not a simple period-loss artifact. Petrie separately states the chamber ends up only 'about 47 inches' E of the pyramid centre (see next record) -- the two figures use different reference points (N-face midpoint at the entrance vs. pyramid centre at the chamber) and are not directly comparable; no arithmetic inconsistency should be assumed without checking the plate.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104",
   "section": "73",
   "plate": "",
   "original_value": "47",
   "original_units": "inches",
   "metric_conversion_m": 1.1938,
   "feature": "Great Chamber offset E of Pyramid centre-line (derived by Petrie from azimuth)",
   "confidence": "MEDIUM",
   "notes": "'the chamber lies altogether E. of the Pyramid centre by about 47 inches' -- stated as an approximate derived figure ('about'), not a direct measurement.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104-105",
   "section": "74",
   "plate": "XII (roller, per text)",
   "original_value": "11.7",
   "original_units": "inches",
   "metric_conversion_m": 0.29718,
   "feature": "Distance, end of sloping roof to far side of roof-roll/drum, E side",
   "confidence": "HIGH",
   "notes": "'From the end of the sloping roof to the other side of the roll is 11.7 on E., 11.6 on W.'",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "104-105",
   "section": "74",
   "plate": "",
   "original_value": "11.6",
   "original_units": "inches",
   "metric_conversion_m": 0.29464,
   "feature": "Distance, end of sloping roof to far side of roof-roll/drum, W side",
   "confidence": "HIGH",
   "notes": "Same sentence as above.",
   "row": "upper_entrance"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.38",
   "original_units": "inches",
   "metric_conversion_m": 1.051052,
   "feature": "Passage width at the portcullis (between granite sides, excl. grooves)",
   "confidence": "HIGH",
   "notes": "'the width of the passage being 41.38 there'",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "9.68",
   "original_units": "inches",
   "metric_conversion_m": 0.245872,
   "feature": "Portcullis groove depth, E side",
   "confidence": "HIGH",
   "notes": "'the grooves are 9.68 deep on E. and 10.05 on W.'",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "10.05",
   "original_units": "inches",
   "metric_conversion_m": 0.25527,
   "feature": "Portcullis groove depth, W side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "61.11",
   "original_units": "inches",
   "metric_conversion_m": 1.552194,
   "feature": "Portcullis passage total width incl. both grooves (sum of passage width + groove depths)",
   "confidence": "HIGH",
   "notes": "'making 61.11 in all' -- 41.38 + 9.68 + 10.05 = 61.11, Petrie's own stated total.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "61.14",
   "original_units": "inches",
   "metric_conversion_m": 1.552956,
   "feature": "Portcullis groove-to-groove width, single measurement, front (N)",
   "confidence": "HIGH",
   "notes": "'the width by a single measurement being 61.14 in front, or N., and 61.35 at back, or S.'",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "61.35",
   "original_units": "inches",
   "metric_conversion_m": 1.55829,
   "feature": "Portcullis groove-to-groove width, single measurement, back (S)",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "15.77",
   "original_units": "inches",
   "metric_conversion_m": 0.400558,
   "feature": "Portcullis groove width (aperture), E side",
   "confidence": "HIGH",
   "notes": "'The width of the grooves is 15.77 E., and 15.19 W.'",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "15.19",
   "original_units": "inches",
   "metric_conversion_m": 0.385826,
   "feature": "Portcullis groove width (aperture), W side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "15.5",
   "original_units": "inches",
   "metric_conversion_m": 0.3937,
   "feature": "Portcullis slab thickness (approx.)",
   "confidence": "LOW",
   "notes": "'the stone slab of the portcullis is about [1/4]-inch thinner' than the groove width -- fraction glyph garbled identically in both OCR passes ('^-inch' / '43-inch'), context ('almost the same as the granite leaf in the Great Pyramid, which is 15.14 to 16.28 thick') is consistent with a quarter-inch, but the exact fraction should be checked against the plate. Reported value here is groove width (15.77/15.19) minus an unconfirmed small fraction, i.e. NOT a directly printed figure -- treat as IDENTIFICATION UNCERTAIN.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.4 to 43.0",
   "original_units": "inches",
   "metric_conversion_m": 1.05156,
   "feature": "Extent of granite walling/roofing behind portcullis (transition point to limestone)",
   "confidence": "HIGH",
   "notes": "'The granite walling and roofing ends at 41.4 to 43.0 behind the portcullis.'",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "23.0",
   "original_units": "inches",
   "metric_conversion_m": 0.5842,
   "feature": "Rise in passage roof height beyond portcullis, at the limestone transition",
   "confidence": "LOW",
   "notes": "Original prints 'the passage roof immediately rises 230' with no visible decimal point in either OCR pass. Read as inches this is physically consistent with the jump from entrance-passage height (47.29) to horizontal-passage height (71.06): 71.06-47.29=23.77, close to 23.0. Could also be a misprint or different figure -- verify against plate/page image before use.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "70.76",
   "original_units": "inches",
   "metric_conversion_m": 1.797304,
   "feature": "Horizontal passage height, E side, near portcullis",
   "confidence": "HIGH",
   "notes": "Table: 'Near portcullis'.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "70.38",
   "original_units": "inches",
   "metric_conversion_m": 1.787652,
   "feature": "Horizontal passage height, W side, near portcullis",
   "confidence": "HIGH",
   "notes": "Table: 'Near portcullis'.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.56",
   "original_units": "inches",
   "metric_conversion_m": 1.055624,
   "feature": "Horizontal passage width, Top, near portcullis",
   "confidence": "HIGH",
   "notes": "Table: 'Near portcullis'.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.78",
   "original_units": "inches",
   "metric_conversion_m": 1.061212,
   "feature": "Horizontal passage width, Base, near portcullis",
   "confidence": "HIGH",
   "notes": "Table: 'Near portcullis'.",
   "row": "portcullis"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "71.53",
   "original_units": "inches",
   "metric_conversion_m": 1.816862,
   "feature": "Horizontal passage height, E side, beyond gaps in floor",
   "confidence": "HIGH",
   "notes": "Table: 'Beyond gaps in floor'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "71.36",
   "original_units": "inches",
   "metric_conversion_m": 1.812544,
   "feature": "Horizontal passage height, W side, beyond gaps in floor",
   "confidence": "HIGH",
   "notes": "Table: 'Beyond gaps in floor'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.65",
   "original_units": "inches",
   "metric_conversion_m": 1.05791,
   "feature": "Horizontal passage width, Top, beyond gaps in floor",
   "confidence": "HIGH",
   "notes": "Table: 'Beyond gaps in floor'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.55",
   "original_units": "inches",
   "metric_conversion_m": 1.05537,
   "feature": "Horizontal passage width, Base, beyond gaps in floor",
   "confidence": "HIGH",
   "notes": "Table: 'Beyond gaps in floor'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "71.27",
   "original_units": "inches",
   "metric_conversion_m": 1.810258,
   "feature": "Horizontal passage height, E side, near chamber",
   "confidence": "HIGH",
   "notes": "Table: 'Near chamber'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "71.10",
   "original_units": "inches",
   "metric_conversion_m": 1.80594,
   "feature": "Horizontal passage height, W side, near chamber",
   "confidence": "HIGH",
   "notes": "Table: 'Near chamber'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.70",
   "original_units": "inches",
   "metric_conversion_m": 1.05918,
   "feature": "Horizontal passage width, Top, near chamber",
   "confidence": "HIGH",
   "notes": "Table: 'Near chamber'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.30",
   "original_units": "inches",
   "metric_conversion_m": 1.04902,
   "feature": "Horizontal passage width, Base, near chamber",
   "confidence": "HIGH",
   "notes": "Table: 'Near chamber'.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "71.06 ± 0.13",
   "original_units": "inches",
   "metric_conversion_m": 1.804924,
   "feature": "Horizontal passage mean height",
   "confidence": "HIGH",
   "notes": "Petrie's own stated mean, with probable error. 'The intention in the 71 inch height seems to be to make it half as high again as the ordinary passage: 71.06 x 2/3 = 47.38 ± 0.09; and the other passage is 47.29 ± 0.03.'",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105",
   "section": "74",
   "plate": "",
   "original_value": "41.59 ± 0.04",
   "original_units": "inches",
   "metric_conversion_m": 1.056386,
   "feature": "Horizontal passage mean width",
   "confidence": "HIGH",
   "notes": "Petrie's own stated mean, with probable error.",
   "row": "upper_horizontal"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "VII (plan)",
   "original_value": "195.8",
   "original_units": "inches",
   "metric_conversion_m": 4.97332,
   "feature": "Great Chamber width, E side",
   "confidence": "HIGH",
   "notes": "'The chamber is, 195.8 on E., 195.9 on W.; 557.9 on N., 557.4 on S.; 206.4 high at N.W.; 206.3 and 206.5(?) at S.W.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "195.9",
   "original_units": "inches",
   "metric_conversion_m": 4.97586,
   "feature": "Great Chamber width, W side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "557.9",
   "original_units": "inches",
   "metric_conversion_m": 14.17066,
   "feature": "Great Chamber length, N side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "557.4",
   "original_units": "inches",
   "metric_conversion_m": 14.15796,
   "feature": "Great Chamber length, S side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "206.4",
   "original_units": "inches",
   "metric_conversion_m": 5.24256,
   "feature": "Great Chamber height at N.W. corner",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "206.3",
   "original_units": "inches",
   "metric_conversion_m": 5.24002,
   "feature": "Great Chamber height at S.W. corner (first reading)",
   "confidence": "MEDIUM",
   "notes": "Petrie prints two readings with his own query mark: '206.3 and 206.5(?) at S.W.' -- the '(?)' is Petrie's own uncertainty notation, retained here.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "105-106",
   "section": "75",
   "plate": "",
   "original_value": "206.5",
   "original_units": "inches",
   "metric_conversion_m": 5.2451,
   "feature": "Great Chamber height at S.W. corner (second reading, Petrie's own '?')",
   "confidence": "MEDIUM",
   "notes": "Petrie's own uncertainty mark '(?)' retained -- he was not fully confident of this reading himself.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "38",
   "original_units": "inches",
   "metric_conversion_m": 0.9652,
   "feature": "Gable roof rise, as given by Vyse (measured from wall base, not floor)",
   "confidence": "HIGH",
   "notes": "'Vyse gives 38 inches for the gable roof rise (though measuring the height from the wall base instead of the floor)'. This is Vyse's figure as reported by Petrie, not Petrie's own independent measurement.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "244.4",
   "original_units": "inches",
   "metric_conversion_m": 6.20776,
   "feature": "Height of chamber ends (gable apex), derived from Vyse's rise + floor-based height",
   "confidence": "HIGH",
   "notes": "'this gives 244.4 for the height of the ends.' Derived by Petrie from the 206.4 wall height plus the 38-inch Vyse rise, restated cleanly in the ch. XXI theory table (p.202/203) as 'End height 244.4'.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "104.3 to 144.9",
   "original_units": "inches",
   "metric_conversion_m": 2.64922,
   "feature": "Doorway position on N wall of Great Chamber, measured from E wall",
   "confidence": "HIGH",
   "notes": "'The doorway is on the N. wall at 104.3 to 144.9 from the E. wall.' The 144.9 figure is independently restated in the ch. XXI theory table as 'Length E. 144.9' (=50 cubits), confirming the reading.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "198.3",
   "original_units": "inches",
   "metric_conversion_m": 5.03682,
   "feature": "Red vertical line position, N wall, from E",
   "confidence": "HIGH",
   "notes": "'On both N. and S. walls there is a vertical red line drawn, on the N. at 198.3 from E., and on the S. at 198.6 from E.'",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "198.6",
   "original_units": "inches",
   "metric_conversion_m": 5.04444,
   "feature": "Red vertical line position, S wall, from E",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "",
   "original_units": "inches",
   "metric_conversion_m": null,
   "feature": "Air-channel-beginning holes and adjoining squares, N and S walls of Great Chamber (dimensions)",
   "confidence": "LOW",
   "notes": "Petrie gives a dense sub-table (hole Top/Base/Deep x E/W, adjoining 'square' Top/Base x E/W, and distance to ceiling / to square) for N and S walls. Both independent OCR passes render this table with garbled/shifted cell alignment in different ways (sample raw OCR, pass 1: 'N. 11-5 10-5 8-8 9-1 11-5 12-2 11-8 8-7 9-0 53-6 62-8'; pass 2: 'N.. rrs 11:2 88 jor r15ir22 r1-8 8:7 go 53.6 62.8'). Individual cell values cannot be reliably assigned to their correct row/column without checking the original plate image; reported here as IDENTIFICATION UNCERTAIN / NOT RELIABLY TRANSCRIBABLE from OCR. The two 'to Ceiling / to Square' totals (53.6 and 62.8 for N; 55.2 and 62.1 for S) are the most legible tokens and recur consistently in both passes.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "43.1",
   "original_units": "inches",
   "metric_conversion_m": 1.09474,
   "feature": "Coffer distance from W wall, N end (before 0.5in shift correction)",
   "confidence": "HIGH",
   "notes": "'The coffer is on the outside 43.1 at N., and 42.9 at S. end, distant from W. wall; increased now by .5 in shifting it.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "42.9",
   "original_units": "inches",
   "metric_conversion_m": 1.08966,
   "feature": "Coffer distance from W wall, S end (before 0.5in shift correction)",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "42.5",
   "original_units": "inches",
   "metric_conversion_m": 1.0795,
   "feature": "Coffer distance to N wall",
   "confidence": "HIGH",
   "notes": "'To the N. wall it is 42.5, and to the S. wall 50.0.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106",
   "section": "75",
   "plate": "",
   "original_value": "50.0",
   "original_units": "inches",
   "metric_conversion_m": 1.27,
   "feature": "Coffer distance to S wall",
   "confidence": "MEDIUM",
   "notes": "Same sentence; final digit '50.0' legible in one OCR pass ('wall 500'), garbled in the other ('so\"a') -- moderate confidence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "206.4",
   "original_units": "inches",
   "metric_conversion_m": 5.24256,
   "feature": "Great Chamber wall height (restated in 'squares of cubits' theory table)",
   "confidence": "HIGH",
   "notes": "Restatement, identical value, of the sect.75 measurement: 'Wall height 206.4 squared = 100 square cubits of 20.640'.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "244.4",
   "original_units": "inches",
   "metric_conversion_m": 6.20776,
   "feature": "Great Chamber end height (restated in theory table)",
   "confidence": "HIGH",
   "notes": "'End height 244.4 = 140 square cubits of 20.656' -- restatement of the derived figure from sect. 75.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "195.85",
   "original_units": "inches",
   "metric_conversion_m": 4.97459,
   "feature": "Great Chamber breadth (restated, theory table -- mean of E 195.8 / W 195.9)",
   "confidence": "HIGH",
   "notes": "'Breadth 195.85 = 93 square cubits of 20.644' -- this is the mean of the raw 195.8(E)/195.9(W) readings from sect. 75, stated to one further decimal.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "412.75",
   "original_units": "inches",
   "metric_conversion_m": 10.48385,
   "feature": "Great Chamber length, W of doorway, to W wall (restated, theory table)",
   "confidence": "HIGH",
   "notes": "'Length W. from door 412.75 = 40 square cubits of 20.637' -- 'the wall W. of the door being a double square, 10x20 cubits, equal to the floor of the King's Chamber.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "144.9",
   "original_units": "inches",
   "metric_conversion_m": 3.68046,
   "feature": "Great Chamber length, E of doorway, to E wall (restated, theory table)",
   "confidence": "HIGH",
   "notes": "'Length E. 144.9 = 50 square cubits of 20.493' -- matches the upper bound of the doorway span (104.3 to 144.9 from E wall) given in sect. 75.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "411.6",
   "original_units": "inches",
   "metric_conversion_m": 10.45464,
   "feature": "Lower chamber length (restated as 'evidently 20 cubits')",
   "confidence": "HIGH",
   "notes": "'The length 411.6 being evidently 20 cubits of 20.58' -- cross-check against raw sect.78 readings of 411.9 (N) / 411.2 (S).",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "202-203",
   "section": "160 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "123.4",
   "original_units": "inches",
   "metric_conversion_m": 3.13436,
   "feature": "Lower chamber breadth (restated as '6 cubits of the passage breadth')",
   "confidence": "HIGH",
   "notes": "'the breadth, 123.4, three times the passage breadth, or 6 cubits of 20.57.' Cross-check against raw sect.78 readings of 123.1 (E) / 123.6 (W).",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106-107",
   "section": "76",
   "plate": "",
   "original_value": "0.20",
   "original_units": "inches",
   "metric_conversion_m": 0.00508,
   "feature": "Coffer bottom, sawing-error depth (worst part cut deeper than dressed level)",
   "confidence": "HIGH",
   "notes": "'the worst part of the sawing being cut .20 deeper than the dressed part.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "103.68 ± 0.02",
   "original_units": "inches",
   "metric_conversion_m": 2.633472,
   "feature": "Coffer outer length, mean",
   "confidence": "HIGH",
   "notes": "Mean stated at end of the outer-length sub-table (sect.77); independently restated identically in ch.XXI theory table (p.203/204): 'Outer length 103.68 (max. 103.73)'.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "103.73",
   "original_units": "inches",
   "metric_conversion_m": 2.634742,
   "feature": "Coffer outer length, maximum single reading",
   "confidence": "HIGH",
   "notes": "Ch. XXI restatement: 'Outer length 103.68 (max. 103.73)'; consistent with the highest raw sub-reading in the sect.77 table.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "42.0",
   "original_units": "inches",
   "metric_conversion_m": 1.0668,
   "feature": "Coffer outer width (stated in prose, rounded)",
   "confidence": "HIGH",
   "notes": "'This coffer being 42.0 inches wide, can never have been taken through the passages, as the upper passage is only 41.3 wide, and the lower is 41.2 and 41.6.' The full E/Mid/W x Top/Mid/Base sub-matrix for outer width is present in sect.77 but its cell alignment is corrupted differently in each OCR pass (values cluster 41.90-42.00); only this rounded prose figure of 42.0 is reported with confidence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107-108",
   "section": "77",
   "plate": "",
   "original_value": "38.12",
   "original_units": "inches",
   "metric_conversion_m": 0.968248,
   "feature": "Coffer outer height, dressed part (constant, 'intended' height)",
   "confidence": "HIGH",
   "notes": "'On the outside bottom the height is constant all over the dressed part, being 38.12' -- a clean prose restatement, independent of the garbled sub-table, of the E-column readings (38.12, 38.12, 37.98) in the sect.77 table.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "203-204",
   "section": "161 (Ch. XXI, theory)",
   "plate": "",
   "original_value": "46.34",
   "original_units": "inches",
   "metric_conversion_m": 1.177036,
   "feature": "Coffer outer height + lid, combined (restated, theory table)",
   "confidence": "HIGH",
   "notes": "'Outer height + lid, 46.34' vs. a theoretical unit value of 46.42; not stated elsewhere in the chapter as a standalone figure.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "7.64 ± 0.01",
   "original_units": "inches",
   "metric_conversion_m": 0.194056,
   "feature": "Coffer side thickness at top, E side",
   "confidence": "HIGH",
   "notes": "Ch. XXI theory restatement: 'Thickness of sides, 7.64 ± .01 | 7.62' -- consistent with raw sect.77 sub-table E-column readings (7.65, 7.66, 7.59).",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "7.62",
   "original_units": "inches",
   "metric_conversion_m": 0.193548,
   "feature": "Coffer side thickness at top, W side (comparison figure)",
   "confidence": "MEDIUM",
   "notes": "Ch. XXI theory table gives '7.62' alongside the E-side 7.64±.01 figure, stated as '= 1/4 of outer height' (fraction glyph garbled in OCR); raw sect.77 W-column sub-readings (7.62, 7.64, 7.70) are broadly consistent but the exact cell-to-mean mapping in that sub-table is not fully certain.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "84.73 ± 0.02",
   "original_units": "inches",
   "metric_conversion_m": 2.152142,
   "feature": "Coffer inner length",
   "confidence": "HIGH",
   "notes": "Stated identically in sect.77 (Ch.IX table) and restated in ch.XXI theory table twice: 'Internal length of coffer 84.73 ± .02 | 84.75 ± .01 = 1/100 of Second Pyramid base' and 'Inner length, 84.73' vs unit value 84.75.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "26.69",
   "original_units": "inches",
   "metric_conversion_m": 0.677926,
   "feature": "Coffer inner width, mean",
   "confidence": "HIGH",
   "notes": "Ch. XXI theory restatement: 'Inner width 26.69 (max. 26.79)'; consistent with raw sect.77 sub-table readings clustering 26.66-26.79.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "26.79",
   "original_units": "inches",
   "metric_conversion_m": 0.680466,
   "feature": "Coffer inner width, maximum single reading",
   "confidence": "HIGH",
   "notes": "Ch. XXI theory restatement: 'Inner width 26.69 (max. 26.79)'.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "29.59",
   "original_units": "inches",
   "metric_conversion_m": 0.751586,
   "feature": "Coffer inner depth, East side (approx. mean of 3 sub-readings)",
   "confidence": "MEDIUM",
   "notes": "Sect.77 table, East column readings 29.51/29.58/29.62 (one OCR pass) vs 29.57/29.58/29.62 (other pass), both giving a mean close to 29.59 ± .03. Not independently restated elsewhere in the chapter, so confidence is capped at MEDIUM pending plate verification.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "107",
   "section": "77",
   "plate": "",
   "original_value": "29.61 ± 0.01",
   "original_units": "inches",
   "metric_conversion_m": 0.752094,
   "feature": "Coffer inner depth, West side (mean of 2 sub-readings)",
   "confidence": "MEDIUM",
   "notes": "Sect.77 table, West column readings 29.68/29.61 (or 29.59/29.68 in the other OCR pass), mean 29.61 ± .01 legible consistently in both passes for the mean/error pair specifically.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "1.70 ± 0.02",
   "original_units": "inches",
   "metric_conversion_m": 0.04318,
   "feature": "Coffer ledge depth, approx. overall mean",
   "confidence": "LOW",
   "notes": "Sect.77 gives a further N/Mid/S (or E/W, table structure ambiguous) sub-matrix for ledge depth with raw readings around 1.60-1.76; a mean of '1.70 ± .02' appears as an isolated legible token in one OCR pass but its exact row/column derivation could not be confirmed against the other pass. Treat as approximate.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "1.20 to 2.30",
   "original_units": "inches",
   "metric_conversion_m": 0.03048,
   "feature": "Ledge width, N side",
   "confidence": "HIGH",
   "notes": "'Ledge wide, 1.20 to 2.30 on N., 1.08 to 1.90 on S.' -- clean, identical in both OCR passes.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "1.08 to 1.90",
   "original_units": "inches",
   "metric_conversion_m": 0.027432,
   "feature": "Ledge width, S side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "0.04",
   "original_units": "inches",
   "metric_conversion_m": 0.001016,
   "feature": "Mean error of all coffer dimensions (Petrie's own summary statement)",
   "confidence": "HIGH",
   "notes": "'The mean error of the dimensions is thus only .04 inch.' -- Petrie's own headline precision statement for the whole coffer table.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "1.07",
   "original_units": "inches",
   "metric_conversion_m": 0.027178,
   "feature": "Coffer lid pin-holes, average diameter",
   "confidence": "HIGH",
   "notes": "'The two pin-holes in the top of the W. side are cut with a tube drill, and average 1.07 diameter.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "5.40 to 6.42",
   "original_units": "inches",
   "metric_conversion_m": 0.13716,
   "feature": "N pin-hole position, from N inner end",
   "confidence": "HIGH",
   "notes": "'N. hole 5.40 to 6.42 from N. inner end. 3.76 to 4.84 from W. outside.'",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "3.76 to 4.84",
   "original_units": "inches",
   "metric_conversion_m": 0.095504,
   "feature": "N pin-hole position, from W outside",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "5.74 to 6.85",
   "original_units": "inches",
   "metric_conversion_m": 0.145796,
   "feature": "S pin-hole position, from S inner end",
   "confidence": "HIGH",
   "notes": "'S. hole 5.74 to 6.85 from S. [inner end]. 3.86 to 4.92 from W. outside.'",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "3.86 to 4.92",
   "original_units": "inches",
   "metric_conversion_m": 0.098044,
   "feature": "S pin-hole position, from W outside",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "103.73",
   "original_units": "inches",
   "metric_conversion_m": 2.634742,
   "feature": "Coffer lid, width on W side",
   "confidence": "HIGH",
   "notes": "'Lid, 103.73 on W., 42.03 on S.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "42.03",
   "original_units": "inches",
   "metric_conversion_m": 1.067562,
   "feature": "Coffer lid, width on S side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "9.89",
   "original_units": "inches",
   "metric_conversion_m": 0.251206,
   "feature": "Coffer lid thickness at W.S.W.",
   "confidence": "HIGH",
   "notes": "'Thickness, 9.89 W.S.W., 8.20 S.S.W., 8.22 S., 8.24 S.E.'",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "8.20",
   "original_units": "inches",
   "metric_conversion_m": 0.20828,
   "feature": "Coffer lid thickness at S.S.W.",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "8.22",
   "original_units": "inches",
   "metric_conversion_m": 0.208788,
   "feature": "Coffer lid thickness at S.",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108",
   "section": "77",
   "plate": "",
   "original_value": "8.24",
   "original_units": "inches",
   "metric_conversion_m": 0.209296,
   "feature": "Coffer lid thickness at S.E.",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "burial_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "106-107",
   "section": "76",
   "plate": "",
   "original_value": "0.25 to 1",
   "original_units": "inches",
   "metric_conversion_m": 0.00635,
   "feature": "Depth pins sank into resin-filled holes when lid was closed",
   "confidence": "MEDIUM",
   "notes": "'the pins sank 1/4 inch to 1 inch, melting their way into the resin' -- OCR renders the fraction as an unclear glyph ('\\ inch') in both passes but context (a small bronze locating pin) strongly supports 1/4 inch as the lower bound.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "VII (plan)",
   "original_value": "411.9",
   "original_units": "inches",
   "metric_conversion_m": 10.46226,
   "feature": "Lower chamber length, N side",
   "confidence": "HIGH",
   "notes": "'This chamber is 411.9 on N. 411.2 on S. 123.1 on E. 123.6 on W.'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "411.2",
   "original_units": "inches",
   "metric_conversion_m": 10.44448,
   "feature": "Lower chamber length, S side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "123.1",
   "original_units": "inches",
   "metric_conversion_m": 3.12674,
   "feature": "Lower chamber width, E side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "123.6",
   "original_units": "inches",
   "metric_conversion_m": 3.13944,
   "feature": "Lower chamber width, W side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "6",
   "original_units": "inches",
   "metric_conversion_m": 0.1524,
   "feature": "Lower chamber roof, excess material removed before replastering (approx.)",
   "confidence": "HIGH",
   "notes": "'on the roof even 6 inches too much having been taken off, and then plastered up' -- Petrie's own approximate figure ('even 6 inches').",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "41.2",
   "original_units": "inches",
   "metric_conversion_m": 1.04648,
   "feature": "Doorway (E side of lower chamber) width",
   "confidence": "HIGH",
   "notes": "'The door in the E. side is 41.2 wide; and 40.9 from N., 41.0 from S. side.'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "40.9",
   "original_units": "inches",
   "metric_conversion_m": 1.03886,
   "feature": "Doorway (E side of lower chamber), distance from N side of passage",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "41.0",
   "original_units": "inches",
   "metric_conversion_m": 1.0414,
   "feature": "Doorway (E side of lower chamber), distance from S side of passage",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "41.0",
   "original_units": "inches",
   "metric_conversion_m": 1.0414,
   "feature": "Short sloping passage into lower chamber, width at top / branch point",
   "confidence": "HIGH",
   "notes": "'The short sloping passage into the chamber is 41.0 wide at top, where it branches from the other passage, which is 41.2 and 41.6 wide.'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "41.2 and 41.6",
   "original_units": "inches",
   "metric_conversion_m": 1.04648,
   "feature": "Horizontal descending passage width at the branch point (two readings)",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "other"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "123.8",
   "original_units": "inches",
   "metric_conversion_m": 3.14452,
   "feature": "Recess opposite lower-chamber passage, length in front (W)",
   "confidence": "HIGH",
   "notes": "'The recess opposite the passage into the chamber is 123.8 long in front (W.), 122.0 at back (E.)'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "122.0",
   "original_units": "inches",
   "metric_conversion_m": 3.0988,
   "feature": "Recess opposite lower-chamber passage, length at back (E)",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "68.2",
   "original_units": "inches",
   "metric_conversion_m": 1.73228,
   "feature": "Recess opposite lower-chamber passage, width on N",
   "confidence": "HIGH",
   "notes": "'and 68.2 wide on N., 67.8 on S., beside the width of the passage'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "67.8",
   "original_units": "inches",
   "metric_conversion_m": 1.72212,
   "feature": "Recess opposite lower-chamber passage, width on S",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "109.4",
   "original_units": "inches",
   "metric_conversion_m": 2.77876,
   "feature": "Recess + passage, total width, N side",
   "confidence": "HIGH",
   "notes": "'which makes a total of 109.4 N., and 109.4 S.'",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "109.4",
   "original_units": "inches",
   "metric_conversion_m": 2.77876,
   "feature": "Recess + passage, total width, S side",
   "confidence": "HIGH",
   "notes": "Same sentence.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Petrie 1883",
   "author": "W.M.F. Petrie",
   "publication": "The Pyramids and Temples of Gizeh",
   "year": 1883,
   "page": "108-109",
   "section": "78",
   "plate": "",
   "original_value": "40 x 105",
   "original_units": "inches",
   "metric_conversion_m": 1.016,
   "feature": "Coffin size implied for lower chamber (Petrie's inference, not a direct measurement)",
   "confidence": "MEDIUM",
   "notes": "'This shows that it was intended to introduce a coffin into the lower chamber, about 40 x 105 long.' Explicitly Petrie's inferred/approximate figure ('about'), not a directly measured architectural dimension.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "114",
   "plate": "",
   "original_value": "eleven feet ten inches",
   "original_units": "ft in",
   "metric_conversion_m": 3.6068,
   "feature": "rock foundation step, south-western corner, height above pyramid base",
   "confidence": "high",
   "notes": "Narrative text (not the Table of Dimensions): 'the rock has been merely stepped up in horizontal layers, and it appears at the south-western corner eleven feet ten inches, and at the north-western fourteen feet three inches above the base.' Read from djvu text, unambiguous spelled-out number, page confirmed via Vol. II TOC (Second Pyramid begins p.114).",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "114",
   "plate": "",
   "original_value": "fourteen feet three inches",
   "original_units": "ft in",
   "metric_conversion_m": 4.3434,
   "feature": "rock foundation step, north-western corner, height above pyramid base",
   "confidence": "high",
   "notes": "Same sentence as SW-corner value above.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "115",
   "plate": "",
   "original_value": "about seven or eight feet",
   "original_units": "ft",
   "metric_conversion_m": 2.1336,
   "feature": "granite facing/lining, lower two tiers of casing - height (approximate, range given as printed)",
   "confidence": "high",
   "notes": "Verbatim: 'The two lower tiers, about seven or eight feet in height, have been facings of granite, as Herodotus has truly described; but, with the exception of the entrance-passage (likewise composed of that material), the masonry is by no means equal to that of the Great Pyramid.' Confirms granite lining extended to the entrance-passage as well as the lower casing tiers. metric_conversion_m computed on the lower bound (7 ft); upper bound is 8 ft = 2.4384 m - author gave an explicit range, not a single figure.",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "115",
   "plate": "",
   "original_value": "about nine feet square",
   "original_units": "ft",
   "metric_conversion_m": 2.7432,
   "feature": "summit platform, present condition (top of pyramid, stones thrown down)",
   "confidence": "high",
   "notes": "'the top of it is, at present, about nine feet square' - matches Table of Dimensions entry 'Square of platform on the top about - 9 0' on p.117.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "115",
   "plate": "",
   "original_value": "130 to 150",
   "original_units": "ft (range, casing remnant distance below present top)",
   "metric_conversion_m": null,
   "feature": "extent of remaining original casing, measured down from present summit",
   "confidence": "high",
   "notes": "'the casing has also been removed to within 130 to 150 feet of the present summit.' Range as printed, not converted (min 39.624 m / max 45.72 m if converted). Matches Table of Dimensions p.117: 'From present top to bottom of casing from 130 to 150 ft.'",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "707 ft. 9 in.",
   "original_units": "ft in",
   "metric_conversion_m": 215.7708,
   "feature": "Second Pyramid, former base (side length)",
   "confidence": "high",
   "notes": "TABLE OF DIMENSIONS. Value verified directly against page image (archive.org operationscarri01vysegoog, leaf 163).",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "690 ft. 9 in.",
   "original_units": "ft in",
   "metric_conversion_m": 210.5748,
   "feature": "Second Pyramid, present base (side length)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "454 ft. 3 in.",
   "original_units": "ft in",
   "metric_conversion_m": 138.4356,
   "feature": "Second Pyramid, former height, perpendicular",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "447 ft. 6 in.",
   "original_units": "ft in",
   "metric_conversion_m": 136.398,
   "feature": "Second Pyramid, present height, perpendicular",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163 (clear print: '447  6'). Flagging for the record: the OCR full-text layer of one archive.org scan (operationscarri01vysegoog djvu.txt) misreads this as '417 6'; a second independent scan (operationscarri02vysegoog djvu.txt) OCRs it correctly as '447 6'. The page-image read is authoritative and resolves the conflict; internal cross-check (half-base vs. inclined height via Pythagorean relation against the printed 'present height, inclined = 563 ft 6 in') is consistent with 447 ft 6 in, not 417 ft 6 in.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "572 ft. 6 in.",
   "original_units": "ft in",
   "metric_conversion_m": 174.498,
   "feature": "Second Pyramid, former height, inclined (slant height)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "563 ft. 6 in.",
   "original_units": "ft in",
   "metric_conversion_m": 171.7548,
   "feature": "Second Pyramid, present height, inclined (slant height)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "52 deg. 20 min.",
   "original_units": "degrees minutes (angle of casing/face)",
   "metric_conversion_m": null,
   "feature": "Second Pyramid, angle of the building (face slope)",
   "confidence": "high",
   "notes": "Printed as 'Angle 52° 20'.' directly beneath the base/height rows. Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "9 ft. 0 in.",
   "original_units": "ft in (side of square)",
   "metric_conversion_m": 2.7432,
   "feature": "Second Pyramid, square of platform on the top, about",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "37 ft. 8 in.",
   "original_units": "ft in",
   "metric_conversion_m": 11.4833,
   "feature": "Upper entrance-passage, height of the bottom above the base of the pyramid",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163. Note printed above this row: 'This passage has lost much of its original length owing to the dilapidated state of the exterior of the building.'",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "43 ft. 10 in.",
   "original_units": "ft in",
   "metric_conversion_m": 13.3604,
   "feature": "Upper entrance-passage, centre of passage eastward from the centre of pyramid",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "117",
   "plate": "",
   "original_value": "25 deg. 55 min.",
   "original_units": "degrees minutes",
   "metric_conversion_m": null,
   "feature": "Upper entrance-passage, angle of descent",
   "confidence": "high",
   "notes": "Verified against page image, leaf 163.",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "104 ft. 10 in.",
   "original_units": "ft in",
   "metric_conversion_m": 31.9532,
   "feature": "Length from first covering-stone to horizontal passage",
   "confidence": "high",
   "notes": "TABLE OF DIMENSIONS continues from p.117. Verified directly against page image (leaf 164).",
   "row": "upper_horizontal"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 3 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0033,
   "feature": "Horizontal passage to portcullis, length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "1 ft. 3 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 0.3937,
   "feature": "Thickness of portcullis (upper entrance-passage portcullis)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 5 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0541,
   "feature": "From portcullis to the end of granite, length (granite lining extent of upper passage)",
   "confidence": "high",
   "notes": "This row directly gives the extent of granite lining beyond the portcullis. Verified against page image, leaf 164.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 5 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0541,
   "feature": "Breadth of passage from portcullis to end of granite",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 11 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.1938,
   "feature": "Height of passage from portcullis to end of granite",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "14 ft. 2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 4.318,
   "feature": "From end of granite to first descent, length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164. Marks the point where granite lining ends and limestone passage continues to the first descent.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "5 ft. 10 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.778,
   "feature": "Height of passage, end of granite to first descent",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 5 1/4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0478,
   "feature": "Breadth of passage, end of granite to first descent",
   "confidence": "medium",
   "notes": "Verified against page image, leaf 164, but the printed fraction glyph on this specific row reads distinctly as a quarter (1/4) rather than the half (1/2) used on adjacent rows - flagged medium confidence on the fraction only, not the whole-number values, given how small the glyph is at this scan resolution.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "6 ft. 9 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.0574,
   "feature": "Perpendicular descent to the bottom of M. Caviglia's passage",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "18 ft. 6 in.",
   "original_units": "ft in",
   "metric_conversion_m": 5.6388,
   "feature": "M. Caviglia's inclined passage, length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "21 deg. 40 min.",
   "original_units": "degrees minutes",
   "metric_conversion_m": null,
   "feature": "M. Caviglia's inclined passage, angle",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "4 ft. 4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.3208,
   "feature": "Depth from floor to lower inclined passage",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "lower_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "8 ft. 7 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.6162,
   "feature": "Length of passage from first descent to second",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "29 ft. 9 in.",
   "original_units": "ft in",
   "metric_conversion_m": 9.0678,
   "feature": "Length of passage from second descent to lower inclined passage",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "connecting"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "128 ft. 4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 39.1262,
   "feature": "From lower inclined passage to Belzoni's Chamber, length",
   "confidence": "high",
   "notes": "This is the horizontal passage running to Belzoni's Chamber. Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 5 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0541,
   "feature": "Breadth, passage from lower inclined passage to Belzoni's Chamber",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "5 ft. 10 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.778,
   "feature": "Height, passage from lower inclined passage to Belzoni's Chamber",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "46 ft. 2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 14.0754,
   "feature": "Belzoni's Chamber, length east and west",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "16 ft. 2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 4.9276,
   "feature": "Belzoni's Chamber, breadth north and south",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "19 ft. 3 in.",
   "original_units": "ft in",
   "metric_conversion_m": 5.8674,
   "feature": "Belzoni's Chamber, height to commencement of roof",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "22 ft. 5 in.",
   "original_units": "ft in",
   "metric_conversion_m": 6.8326,
   "feature": "Belzoni's Chamber, extreme height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164. This is the gable/ridge apex height noted in the earlier task instructions as Belzoni's Chamber roof height.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "8 ft. 7 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.6162,
   "feature": "Belzoni's Chamber, distance from east side to the passage",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "8 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.4384,
   "feature": "Belzoni's Chamber, centre of pyramid west of chamber",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 10 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.1684,
   "feature": "Belzoni's Chamber, centre of pyramid south of chamber",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "16 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 4.8768,
   "feature": "Belzoni's Chamber, extent of floor of rock from the eastern end",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164. Indicates the chamber floor is part-rock, part-pavement (rock for 16 ft from the east end).",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "30 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 9.144,
   "feature": "Belzoni's Chamber, pavement of limestone (extent)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "8 ft. 7 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.6162,
   "feature": "Sarcophagus (Belzoni's Chamber), exterior length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 6 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0795,
   "feature": "Sarcophagus (Belzoni's Chamber), exterior breadth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 0.9144,
   "feature": "Sarcophagus (Belzoni's Chamber), exterior height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "7 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.1336,
   "feature": "Sarcophagus (Belzoni's Chamber), interior length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "2 ft. 2 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 0.6731,
   "feature": "Sarcophagus (Belzoni's Chamber), interior breadth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "2 ft. 5 in.",
   "original_units": "ft in",
   "metric_conversion_m": 0.7366,
   "feature": "Sarcophagus (Belzoni's Chamber), interior depth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "4 ft. 4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.3208,
   "feature": "Sarcophagus (Belzoni's Chamber), distance from southern side of chamber",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 7 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0922,
   "feature": "Sarcophagus (Belzoni's Chamber), distance from western side",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "burial_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "96 ft. 4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 29.369,
   "feature": "Lower inclined passage, length to horizontal passage",
   "confidence": "high",
   "notes": "This is the passage discovered by Belzoni descending from Belzoni's Chamber toward the lower/subsidiary chamber. Verified against page image, leaf 164.",
   "row": "lower_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 5 1/4 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0478,
   "feature": "Lower inclined passage, breadth",
   "confidence": "medium",
   "notes": "Verified against page image, leaf 164; fraction glyph reads as a quarter, flagged medium confidence on the fraction only (see note on the earlier '3 5 1/4' row).",
   "row": "lower_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "3 ft. 11 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.1938,
   "feature": "Lower inclined passage, height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164.",
   "row": "lower_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "118",
   "plate": "",
   "original_value": "21 deg. 40 min.",
   "original_units": "degrees minutes",
   "metric_conversion_m": null,
   "feature": "Lower inclined passage, angle",
   "confidence": "high",
   "notes": "Verified against page image, leaf 164. Printed identically to M. Caviglia's inclined passage angle above it - both rows independently give 21 deg 40 min.",
   "row": "lower_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "23 ft. 11 in.",
   "original_units": "ft in",
   "metric_conversion_m": 7.2898,
   "feature": "Lower horizontal passage, length to inclined entrance to lower chamber",
   "confidence": "high",
   "notes": "Verified directly against page image (leaf 165).",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "26 ft. 5 in.",
   "original_units": "ft in",
   "metric_conversion_m": 8.0518,
   "feature": "Lower horizontal passage, from entrance to lower chamber to portcullis",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "3 ft. 5 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0541,
   "feature": "Lower horizontal passage, breadth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "lower_horizontal"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "5 ft. 11 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.8034,
   "feature": "Lower horizontal passage, height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "lower_horizontal"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "1 ft. 1 in.",
   "original_units": "ft in",
   "metric_conversion_m": 0.3302,
   "feature": "Thickness of portcullis (lower horizontal passage portcullis)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. This is the second, lower portcullis in the Second Pyramid system, distinct from the upper-passage portcullis on p.118.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "100 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 30.48,
   "feature": "From (lower) portcullis to mouth of lower entrance on the exterior of the pyramid",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. This is the length of the separate, lower (subsidiary) entrance passage that opens on the exterior of the pyramid.",
   "row": "portcullis"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "3 ft. 5 1/2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0541,
   "feature": "Lower exterior entrance passage, breadth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "3 ft. 11 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.1938,
   "feature": "Lower exterior entrance passage, height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "upper_entrance"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "22 deg. 15 min.",
   "original_units": "degrees minutes",
   "metric_conversion_m": null,
   "feature": "Lower horizontal/entrance passage system, angle",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "lower_horizontal"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "22 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 6.7056,
   "feature": "Inclined entrance to lower chamber, length",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "3 ft. 5 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.0414,
   "feature": "Inclined entrance to lower chamber, breadth",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165 (no fraction printed on this row, unlike most others in the table).",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "3 ft. 8 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.1176,
   "feature": "Inclined entrance to lower chamber, height",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "20 deg. 50 min.",
   "original_units": "degrees minutes",
   "metric_conversion_m": null,
   "feature": "Inclined entrance to lower chamber, angle",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "34 ft. 1 in.",
   "original_units": "ft in",
   "metric_conversion_m": 10.3886,
   "feature": "Lower (subsidiary) chamber, length east and west",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. This is the small unfinished/subsidiary chamber below Belzoni's Chamber, sometimes called the 'lower chamber'.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "10 ft. 2 in.",
   "original_units": "ft in",
   "metric_conversion_m": 3.1014,
   "feature": "Lower (subsidiary) chamber, breadth north and south",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "6 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 1.8288,
   "feature": "Lower (subsidiary) chamber, height at sides",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "8 ft. 5 in.",
   "original_units": "ft in",
   "metric_conversion_m": 2.5654,
   "feature": "Lower (subsidiary) chamber, height in centre",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. Higher-in-centre implies a low vaulted/pointed rock-cut ceiling, consistent with the narrative's description of similar chambers elsewhere in the appendix.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "36 ft. 0 in.",
   "original_units": "ft in",
   "metric_conversion_m": 10.9728,
   "feature": "Pavement, width from the base in centre of northern front",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "71,670,000 cubic feet / 5,309,000 tons",
   "original_units": "cubic feet / tons",
   "metric_conversion_m": null,
   "feature": "Original (former) quantity of masonry, estimated",
   "confidence": "high",
   "notes": "Not a linear dimension - included for completeness. Verified against page image, leaf 165. Caveat printed in the source itself: 'Supposing the rock to average eight feet over the extent of base, the original quantity of masonry would be...' - i.e. an estimate, not a direct measurement. No metric conversion computed (volume/mass figures, not a length).",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "65,928,000 cubic feet / 4,883,000 tons",
   "original_units": "cubic feet / tons",
   "metric_conversion_m": null,
   "feature": "Present quantity of masonry, estimated",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. Estimate, not a direct measurement.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "11 acres 1 rood 38 poles",
   "original_units": "acres roods poles",
   "metric_conversion_m": null,
   "feature": "Former extent of base (area)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165. Area figure, not converted to metric (out of scope of the linear ft-to-m conversion specified for this extraction).",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "119",
   "plate": "",
   "original_value": "10 acres 3 roods 30 poles",
   "original_units": "acres roods poles",
   "metric_conversion_m": null,
   "feature": "Present extent of base (area)",
   "confidence": "high",
   "notes": "Verified against page image, leaf 165.",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "III (Appendix - J. S. Perring survey)",
   "page": "",
   "plate": "",
   "original_value": "NOT REPORTED",
   "original_units": "",
   "metric_conversion_m": null,
   "feature": "Second Pyramid (Giza) interior dimensions in Vyse Vol. III",
   "confidence": "n/a",
   "notes": "Vol. III of this work (archive.org id operationscarri03vysegoog, 1842) is titled 'Appendix to Operations Carried on at the Pyramids of Gizeh... Containing a Survey by J. S. Perring, Civil Engineer, of the Pyramids at Abou Roash, and to the Southward, Including Those in the Faiyoum.' Confirmed by direct read of its title page in the djvu text. It covers Abu Roash, Zawyet el-Aryan, Dahshur, Lisht, Meydum, Lahun, Hawara etc. - NOT the Giza Second Pyramid, whose admeasurements are instead in Vol. II's own appendix (records above). No Second Pyramid content found in Vol. III.",
   "row": "other"
  },
  {
   "source": "Perring",
   "author": "J. S. Perring",
   "publication": "The Pyramids of Gizeh: From Actual Survey and Admeasurement (plates volume)",
   "year": 1839,
   "volume": "",
   "page": "",
   "plate": "",
   "original_value": "NOT REPORTED",
   "original_units": "",
   "metric_conversion_m": null,
   "feature": "Perring's independently-published plates volume on the Pyramids of Gizeh",
   "confidence": "n/a",
   "notes": "Searched archive.org (title search 'pyramids gizeh actual survey admeasurement' and general keyword searches) - this separate Perring atlas/plates work was NOT found as a digitized item on archive.org under this or related titles. IDENTIFICATION UNCERTAIN whether it exists there under an unrecognized identifier; not located within the time available for this task. Perring's actual survey data for the Second Pyramid is available instead through his collaboration credited throughout Vyse Vol. II (explicit statements e.g. 'Mr. Perring is of opinion that the interior is divided by massive walls...' p.115, and Vol. III title page crediting Perring, civil engineer, as surveyor).",
   "row": "other"
  },
  {
   "source": "Vyse/Perring",
   "author": "Howard Vyse",
   "publication": "Operations Carried on at the Pyramids of Gizeh in 1837: with an Account of a Voyage into Upper Egypt, and an Appendix",
   "year": 1840,
   "volume": "II",
   "page": "31-39",
   "plate": "",
   "original_value": "NOT REPORTED",
   "original_units": "",
   "metric_conversion_m": null,
   "feature": "Diary/journal narrative of the June 1837 Belzoni's Chamber excavation work",
   "confidence": "n/a",
   "notes": "Pages 31-39 of Vyse Vol. II contain the day-by-day labour diary ('Second Pyramid. - Roof in Belzoni's Chamber' / 'Second Pyramid. - Belzoni's Chamber' repeated as work-log headers for late June-July 1837) but this stretch is administrative/logistical narrative (workforce counts, weather, provisioning, other pyramids' progress) rather than an architectural description with measurements. The substantive descriptive account of the Second Pyramid's structure and construction is instead on pp.114-116 (see records above), immediately preceding the Table of Dimensions. No numeric dimensions were found to extract from pp.31-39 specifically.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51",
   "plate": "TAV. 7",
   "feature": "upper_entrance_general",
   "original_value": "two original entrances, both north, one on the face and one in the courtyard directly below it",
   "original_units": "descriptive",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Archive.org item 51maragiogliovrinaldiclarchitetturadellepiramidimenfitetestolepiramididizedefraedichefren1966lr, _djvu.txt lines 5835-5837. Full djvu.txt (699,992 bytes) downloaded whole via direct HTTP GET from ia600503.us.archive.org, not chunked (file was well under practical limits despite earlier note about it being 'too large').",
   "row": "other"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51",
   "plate": "TAV. 7",
   "feature": "entrance_threshold_height_above_courtyard",
   "original_value": "12,90 (circa 25 cubiti)",
   "original_units": "meters (~25 cubits)",
   "metric_conversion_m": 12.9,
   "confidence": "high",
   "notes": "Original threshold level of upper (face) entrance, fixed by M&R's reconstructed section with 'reasonable approximation'; not directly measured (destroyed with casing). English text line ~5900: 'we may fix it with reasonable approximation at 12.90 m., about 25 cubits, above the level of the surrounding courtyard pavement.' Italian original line ~6033: 'm. 12,90, circa 25 cubiti'.",
   "row": "other"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51",
   "plate": "TAV. 7",
   "feature": "upper_descending_corridor_D_offset_from_face_center",
   "original_value": "12,45 ad est",
   "original_units": "meters",
   "metric_conversion_m": 12.45,
   "confidence": "high",
   "notes": "Descending corridor (D) does not begin at the middle of the north face, but 12.45 m to the east of it. djvu.txt line ~5905/6037.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51",
   "plate": "TAV. 7",
   "feature": "upper_descending_corridor_D_inclination",
   "original_value": "circa 26°46' (main text); 26°30' circa (Osservazioni n.9, measured); Holscher theoretical 26°35' (slope 1/2)",
   "original_units": "degrees/minutes",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "DISCREPANCY IN SOURCE: main narrative text (djvu.txt line ~5908, p.51) states 'Its inclination is about 26°46\\''; the Osservazioni appendix note 9 (djvu.txt line ~12572-12576, p.104) states 'We have calculated the inclination of (D) as about 26°30\\''. Holscher's theoretical value cited alongside note 9 is 26°35' (slope 1/2). Transcribed exactly as found; both values recorded per instruction not to resolve discrepancies silently. Petrie's azimuth for D cited as -5'37\", 11\" different from mean base azimuth.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51",
   "plate": "TAV. 7",
   "feature": "upper_descending_corridor_D_last_granite_block_height_above_courtyard",
   "original_value": "circa m. 11,50",
   "original_units": "meters",
   "metric_conversion_m": 11.5,
   "confidence": "high",
   "notes": "Height of the furthest preserved edge of the last granite floor block of (D), measured from the courtyard pavement. djvu.txt line ~5923.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "51-52",
   "plate": "TAV. 7",
   "feature": "upper_descending_corridor_D_granite_block_dimensions",
   "original_value": "blocks ~3 m long; ceiling blocks thickness 1,40 m; floor blocks thickness 1,20 m; wall block height 1,20 m, thickness ~1 m",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Generic granite block arrangement described for corridor (D): floor/ceiling blocks 'about 3 metres long'; ceiling blocks thickness 1.40 m; floor blocks thickness 1.20 m; wall block height 1.20 m, thickness about 1 metre, length variable. djvu.txt lines 5936-5941.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "52",
   "plate": "TAV. 7",
   "feature": "upper_descending_corridor_D_original_floor_length",
   "original_value": "sui 37 metri",
   "original_units": "meters",
   "metric_conversion_m": 37.0,
   "confidence": "high",
   "notes": "'The original length of the floor of the corridor must have been about 37 metres' - cross-ref Osservazioni n.10. djvu.txt line ~5947, p.52 English col.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "52-53",
   "plate": "TAV. 7 / TAV. 9",
   "feature": "upper_portcullis_S_height_belzoni",
   "original_value": "alto circa m. 1,83",
   "original_units": "meters",
   "metric_conversion_m": 1.83,
   "confidence": "medium",
   "notes": "Belzoni's own reported height of the upper portcullis (S) slab, found lowered ~20cm from floor when discovered. M&R note it is 'at the moment impossible to measure' directly; this is Belzoni's historical figure, possibly obtained via chipping at slab edges. djvu.txt line ~6116.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "53",
   "plate": "TAV. 9",
   "feature": "upper_portcullis_S_slider_depth_and_play",
   "original_value": "sliders ~25 cm deep; play >1 cm; moving block thickness 37 cm; slider width ~0.40 m; floor groove 3-4 cm deep",
   "original_units": "centimeters/meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "'ran on two lateral sliders about 25 centimetres deep. The play... is little more than one centimetre and the thickness of the moving block is 37 centimetres, so that the width of the sliders is about 0.40 m... a groove specially left or dug in the floor 3-4 centimetres deep'. djvu.txt lines 6121-6136.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "53",
   "plate": "TAV. 9",
   "feature": "upper_portcullis_S_facing_thickness_per_Perring",
   "original_value": "walls ~1 m; floor 1,40 m; ceiling 1,70 m",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "'According to Perring's drawings, the thickness of the facing here is about one metre in the walls, 1.40 m in the floor, and 1.70 in the ceiling.' Attributed to Perring's drawings, not M&R's own measurement. djvu.txt lines 6130-6132.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "53",
   "plate": "TAV. 7 / TAV. 9",
   "feature": "horizontal_corridor_L_floor_below_courtyard",
   "original_value": "circa 3 metri sotto il lastricato del cortile",
   "original_units": "meters",
   "metric_conversion_m": 3.0,
   "confidence": "high",
   "notes": "Floor level of horizontal corridor (L), which contains the upper portcullis. djvu.txt line ~6143-6144/6272-6273.",
   "row": "upper_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "53-54",
   "plate": "TAV. 7",
   "feature": "corridor_O_width_and_narrowing",
   "original_value": "ripresa la sua primitiva larghezza di m. 1,05; narrowing at floor gap: 5 cm west, 8 cm east",
   "original_units": "meters/centimeters",
   "metric_conversion_m": 1.05,
   "confidence": "high",
   "notes": "Original/regained width of corridor (O)/(T) beyond the portcullis strongpoint is 1.05 m ('the corridor has regained its original width of 1.05 m'). Near the floor gap it narrows by 5 cm to west, 8 cm to east. djvu.txt lines 6203, 6309-6310.",
   "row": "upper_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "54",
   "plate": "TAV. 7",
   "feature": "passage_G_limestone_facing_central_stretch",
   "original_value": "per circa 11 metri",
   "original_units": "meters",
   "metric_conversion_m": 11.0,
   "confidence": "high",
   "notes": "Central ~11 m stretch of rock-cut passage (G) leading to the crypt is faced with limestone blocks (walls, ceiling, floor) due to bad rock quality. djvu.txt line ~6368.",
   "row": "upper_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "54",
   "plate": "TAV. 7",
   "feature": "belzoni_distance_L_to_trench_T",
   "original_value": "circa 7 metri",
   "original_units": "meters",
   "metric_conversion_m": 7.0,
   "confidence": "high",
   "notes": "'Belzoni continued along (O) for about 7 metres beyond (L) before arriving at a deep trench (T)'. Corridor at trench (T) regains original width of 1.05 m (see above). djvu.txt lines 6198-6203.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "55 (Belzoni's Chamber / crypt C)",
   "plate": "TAV. 10, Fig. 1",
   "feature": "sarcophagus_lid_dimensions",
   "original_value": "cm. 263 x 107 x 21-25",
   "original_units": "centimeters",
   "metric_conversion_m": "2.63 x 1.07 x 0.21-0.25",
   "confidence": "high",
   "notes": "'the lid (which measures 263 x 107 x 21-25 cms.)'. djvu.txt line ~6458/6588.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "56",
   "plate": "TAV. 10",
   "feature": "sarcophagus_coffer_base_block_thickness",
   "original_value": "spessore variante fra i 30 ed i 47 centimetri",
   "original_units": "centimeters",
   "metric_conversion_m": "0.30-0.47",
   "confidence": "high",
   "notes": "Base block under the coffer, thickness varying 30-47 cm, citing Vyse, Operations etc. II p.99. djvu.txt line ~6427-6428.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "56",
   "plate": "TAV. 10",
   "feature": "belzoni_chamber_canopic_pit_dimensions",
   "original_value": "76 cms. east-west x 72 cms. north-south, depth at least 70 cm",
   "original_units": "centimeters",
   "metric_conversion_m": "0.76 x 0.72 x >=0.70",
   "confidence": "high",
   "notes": "Small pit against south wall of the crypt (Belzoni's Chamber), possible canopic receptacle. djvu.txt lines 6638-6641.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "57",
   "plate": "TAV. 10",
   "feature": "belzoni_chamber_butting_beam_penetration_and_thickness",
   "original_value": "penetravano oltre la parete per metri 2,67; spessore circa 2 metri",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "Perring's assay measurement: roof butting beams penetrate 2.67 m beyond the wall they rest on (at the one point examined); thickness from Perring's drawings ~2 metres. 17 pairs of beams visible. Attributed to Perring, Pyramids etc. II, Pl. III. djvu.txt lines 6683-6693.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "57",
   "plate": "TAV. 10, Fig. 1",
   "feature": "belzoni_chamber_height_walls",
   "original_value": "Perring: m. 5,87 (19 ft 3 in); Petrie: m. 5,24 (206.4 in); Vandier: m. 5,24 (10 cubiti) [adopted by M&R]",
   "original_units": "meters/feet-inches/cubits",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "MULTIPLE SOURCE VALUES for the crypt/burial chamber ('Belzoni's Chamber') wall height, all quoted by M&R without direct measurement of their own ('We were unfortunately not able to measure the height of the crypt directly'). M&R adopt Vandier's figures for their drawings (Pl.10 Fig.1). djvu.txt lines 6698, 6717-6718, 6725-6731.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "57",
   "plate": "TAV. 10, Fig. 1",
   "feature": "belzoni_chamber_max_height_apex",
   "original_value": "Perring: m. 6,83 (22 ft 5 in); Petrie (calc.): m. 6,21 (244.4 in) [M&R say this figure 'does not correspond to the truth']; Vandier: m. 6,84 (circa 13 cubiti) [adopted by M&R]",
   "original_units": "meters/feet-inches/cubits",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Maximum height at the apex of the pointed/butting-beam roof of the crypt. M&R explicitly flag Perring's own published section drawing as internally inconsistent with his own stated figures (tympanum height would be >=1.57m per the drawing vs 0.96m per his stated numbers), and reject Petrie's derived 6.21m. They adopt Vandier's 6.84 m for their own drawings, with beam inclination 34°10'. djvu.txt lines 6698-6731.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "57",
   "plate": "TAV. 10",
   "feature": "belzoni_chamber_tympanum_height",
   "original_value": "Perring stated: 0,96 m (38 in); Perring's own drawing implies: at least 1,57 m (62 in)",
   "original_units": "meters/inches",
   "metric_conversion_m": null,
   "confidence": "low",
   "notes": "M&R flag this as Perring's internal contradiction ('it is therefore clear that the author got confused'). Not an M&R measurement. djvu.txt lines 6700-6712.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "58-59",
   "plate": "TAV. 10",
   "feature": "belzoni_chamber_position_from_pyramid_axes",
   "original_value": "west wall 1,19 m from N-S axis (Petrie, correcting Perring); south wall 1,17 m from E-W axis (Perring, uncorrected by Petrie)",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "M&R note Petrie did not appear to correct Perring's E-W axis figure, so accept it 'with the necessary reserve'. djvu.txt lines 6868-6875.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "58",
   "plate": "TAV. 10",
   "feature": "belzoni_chamber_floor_slab_thickness",
   "original_value": "spessore del pavimento 35-40 centimetri",
   "original_units": "centimeters",
   "metric_conversion_m": "0.35-0.40",
   "confidence": "medium",
   "notes": "Osservazioni n.17 (appendix, p.109): thickness of the limestone floor slabs in the crypt, used by M&R to argue against Vyse's claim of two courses of blocks (M&R conclude only one course, except near sarcophagus). Rock beneath floor is 30-40 cm lower than eastern rock floor level per main text (p.56, line ~6407-6408).",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "59-61",
   "plate": "TAV. 8 / TAV. 9",
   "feature": "second_entrance_general",
   "original_value": "second (lower) entrance at foot of north face, directly below upper entrance, originally covered by courtyard paving blocks; whole passage system on same vertical plane",
   "original_units": "descriptive",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "djvu.txt lines 6880-6892.",
   "row": "other"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "60-61",
   "plate": "TAV. 9",
   "feature": "lower_ascending_corridor_A_inclination_and_dimensions",
   "original_value": "inclination avg 21°40'; width ~2 cubits; vertical height 1,30-1,34 m; height perpendicular to slope 1,21-1,235 m",
   "original_units": "meters/degrees/cubits",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Corridor (A), entirely rock-cut, plastered with mortar. 'the coarsely made hole at the bottom of the shaft (X) opens into the ceiling of (A)'. djvu.txt lines 6932-6942.",
   "row": "connecting"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "61",
   "plate": "TAV. 9",
   "feature": "lower_horizontal_corridor_P_height_and_width",
   "original_value": "height 1,83 m; width 2 cubits (same as A)",
   "original_units": "meters/cubits",
   "metric_conversion_m": 1.83,
   "confidence": "high",
   "notes": "Horizontal corridor (P) begins at north end of (A); higher than (A) at 1.83 m, same width. djvu.txt lines 6947-6948.",
   "row": "lower_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "61",
   "plate": "TAV. 9",
   "feature": "lower_corridor_P_east_wall_recess_niche_dimensions",
   "original_value": "m. 3,15 in senso nord-sud, m. 2,76 in senso est-ovest (compresa la larghezza del corridoio), altezza m. 1,64",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Rough, wide recess/niche opposite corridor (R), in east wall of (P). Given twice consistently: main text p.61 ('reaches only 1.64 m') and Osservazioni n.26 (p.114) with full 3-axis dimensions: 3.15 m N-S, 2.76 m E-W (incl. corridor width), height 1.64 m. djvu.txt lines 6952-6954 and 13846-13850.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "61",
   "plate": "TAV. 8 / TAV. 9",
   "feature": "lower_portcullis_M_dimensions",
   "original_value": "present max height 1,23 m (reduced/not in original place); reconstructed original height (calculated from corner-to-seating distance): 1,55 m",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Portcullis (M) at north end of corridor (P), granite, reduced in height. 'The distance of the lower corner of the corridor (I) from the upper end of the seating in the ceiling gives us with very reasonable approximation the height of the block - viz. 1.55 m.' djvu.txt lines 6958-6960, 7121-7124.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "61-62",
   "plate": "TAV. 8",
   "feature": "lower_descending_corridor_I_inclination",
   "original_value": "circa 22°40'",
   "original_units": "degrees/minutes",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Corridor (I), leading from portcullis (M) north to the courtyard, section 'almost equal' to (A). djvu.txt lines 7186-7187.",
   "row": "lower_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "62",
   "plate": "TAV. 8",
   "feature": "lower_descending_corridor_I_plug_blocks",
   "original_value": "plugs found in place for ~11 metres from outside orifice; first plug over 3 metres long",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Per Perring's observations. djvu.txt lines 7191-7195.",
   "row": "lower_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "62-63 (subsidiary/underground chamber N)",
   "plate": "TAV. 9",
   "feature": "subsidiary_chamber_N_general",
   "original_value": "low room with pointed (double-sloping) ceiling, very coarse workmanship; walls show water traces to height of about 30 cm; accessed via inclined corridor (R) from west wall of (P), which had a two-leaf wooden door",
   "original_units": "descriptive/centimeters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "M&R's proposed functional parallel: Chamber (N) = 'underground room (B)' of Cheops (Khufu). No explicit L x W x H figures for chamber (N) itself are given in the main text or Osservazioni beyond the opposite-wall niche dimensions (3.15 x 2.76 x 1.64 m, recorded separately) and the ~30cm water-mark height. djvu.txt lines 7137-7164, 13715-13716.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "154 (Osservazioni no. 3, appendix)",
   "plate": null,
   "feature": "granite_casing_block_example_dimensions",
   "original_value": "profondo m. 2,50, lungo m. 2,53 ed alto m. 1,15",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "Not an interior-passage dimension but a large first-course granite casing block at the pyramid base, cited for context; its size deduced from traces in situ, block itself broken. djvu.txt lines 12054-12055 (p.100 area of Osservazioni).",
   "row": "upper_entrance"
  },
  {
   "source": "Legon_1989_GM110",
   "author": "Legon, John A.R.",
   "publication": "\"The Design of the Pyramid of Khaefre\", Gottinger Miszellen 110",
   "year": 1989,
   "volume": "GM 110",
   "page": "27-34",
   "plate": null,
   "feature": "NOT_OBTAINED",
   "original_value": "NOT REPORTED",
   "original_units": "NOT REPORTED",
   "metric_conversion_m": null,
   "confidence": "n/a",
   "notes": "LEGON: NOT OBTAINED. Full text of this paper could not be located anywhere accessible from this environment. Trail: (1) WebSearch/Google Scholar confirm the citation exists - 'Legon, J.A.R., The Design of the Pyramid of Khaefre, Gottinger Miszellen [110], 27-34 (1989)' via https://scholar.google.co.uk/citations?user=lUlhN1YAAAAJ - but no full-text link is provided there. (2) Legon's personal site legon.demon.co.uk is in the Wayback Machine CDX index (checked via https://web.archive.org/cdx/search/cdx?url=legon.demon.co.uk*), but only the frameset homepage and one unrelated .jpg/.htm path were ever crawled - no article subpages indexed - AND actual Wayback replay (web.archive.org/web/<ts>/...) returned HTTP 503 on every attempt in this environment (both via WebFetch, which explicitly refuses web.archive.org, and via direct curl), so even the homepage content could not be read. timetravel.mementoweb.org did not resolve (DNS failure) as an alternative Memento aggregator. (3) 'legon.uk' (suggested by search-engine summaries as Legon's site) does NOT resolve - confirmed NXDOMAIN by direct nslookup; appears to be a hallucinated/fabricated domain, not a real source. (4) academia.edu profile https://independent.academia.edu/JohnLegon returned HTTP 403 (anti-bot block) via both WebFetch and curl with browser User-Agent; listed academia.edu papers by other authors that cite Legon's GM110 (e.g. Miatello's GM 263 paper on Khafra shafts) were also 403-blocked. (5) Harvard's Digital Giza project (correct live domain: giza.fas.harvard.edu; the commonly-cited 'gizamedia.rc.fas.harvard.edu' and 'giza-web2.rc.fas.harvard.edu' hostnames returned NXDOMAIN) hosts SIX other Legon papers as scanned PDFs on a CloudFront CDN (d1g9lvwdq3dcse.cloudfront.net/documents/legon_*.pdf), confirmed via the author page http://giza.fas.harvard.edu/modernpeople/4884/full/ - but GM 110 / the Khaefre design paper is explicitly NOT among them. Direct URL-guessing for legon_gm_110_1989.pdf on that CDN returned HTTP 403 (Access Denied / object not found), versus HTTP 200 for confirmed real files (e.g. legon_de_10_1988.pdf, legon_de_14_1989.pdf), confirming the object genuinely does not exist there. (6) Downloaded and full-text-searched (pdftotext) the two Legon papers most likely to restate Khaefre passage numbers - 'A Ground Plan at Giza' (Discussions in Egyptology 10, 1988) and 'The Giza Ground Plan and Sphinx' (Discussions in Egyptology 14, 1989) - for all ten requested fingerprint decimals (34.94, 7.88, 6.71, 14.65, 9.69, 39.37, 41.86, 16.02, 2.58, 36.95): ZERO matches in either file. Both papers discuss Khaefre only in terms of overall Giza site-plan triangulation/geometry, not interior passage dimensions. (7) Direct web searches for the fingerprint decimals in combination with 'Khafre pyramid passage meters' returned no hits attributing them to Legon or to any source. CONCLUSION: none of the ten fingerprint values could be confirmed as appearing in any obtainable Legon text; GM110 itself remains unobtained.",
   "row": "other"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "52 (English)/53 (Italian, inferred from djvu.txt sequence - not independently imaged); Osservazioni n.7 (p.102-103)",
   "plate": "TAV. 7",
   "feature": "robbers_thieves_tunnel_gallery_position_and_dimensions",
   "original_value": "Italian original (confirmed via djvu.txt, printed p.53 - the Italian-language continuation immediately following p.52's English column): 'm. 8 - 8,50 di altezza dal suolo, parte una galleria scavata da violatori che si dirige verso sud attraverso la muratura rustica del nucleo' (English parallel text, p.52: 'at about 8-8.50 m. from the ground, starts a gallery dug by robbers which proceeds southwards through the rough masonry of the nucleus'); Osservazioni n.7 (p.103): 'non avrebbero iniziato la loro galleria più in basso ed alla distanza di oltre 12 metri dall'ingresso originale' (they would not have begun their tunnel lower down and at a distance of over 12 metres from the original entrance); p.103 continued: 'un assaggio che giunge fino all'altezza di circa 3 metri dalla base della piramide' (a trial-dig/offshoot that reaches down to a height of about 3 metres from the base of the pyramid, where it stops because it met solid rock in the nucleus)",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "MISSED IN PRIOR PASS. Distinct from the D corridor / original entrance system: this is the illicit robbers' tunnel (post-construction intrusion), first identified from the English-parallel-text page 52 (djvu.txt lines ~5880-5885, confirmed against local image mr-p52.jpg) and elaborated in Osservazioni etc. n.7 (djvu.txt lines ~12570-12600 and ~12610-12650, printed pp.102-103). Three distinct figures: (1) tunnel orifice starts ~8-8.50 m above ground/courtyard level on the pyramid face/nucleus; (2) tunnel begins (horizontally, southward) at a point over 12 m from the original entrance (M&R use this distance as their main argument that the tunnellers did NOT know where the true entrance was); (3) an abandoned oblique trial-dig branch descends to about 3 m above the pyramid base before stopping at solid rock. Path per Perring's drawings: horizontal south, then oblique trial-dig down to ~3m level (abandoned), then resumes at original level, angles slightly east, meets the vertical rock wall at the bottom of the D-corridor/portcullis construction trench, and drops via a small shaft into corridor (O)'s ceiling, right behind the upper portcullis (S). No overall LENGTH of the robbers' tunnel is given (NOT REPORTED).",
   "row": "other"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "59; Osservazioni n.20 (p.109-110)",
   "plate": "TAV. 10",
   "feature": "crypt_C_east_west_wall_incised_rectangular_panel_holes_depth",
   "original_value": "Full sequence (djvu.txt Italian, printed p.59, confirmed also against local image mr-p59.jpg): \"Nelle pareti nord e sud sono chiaramente visibili due righe verticali tracciate in rosso ed alte come le pareti stesse. La riga orientale è in corrispondenza del bordo del pavimento in roccia e l'altra è spostata ad ovest di 23 centimetri. Ad una certa altezza dal pavimento due righe orizzontali distanti fra loro circa 30 centimetri formano con le precedenti un piccolo riquadro. Ancora più in alto è poi disegnato un altro uguale riquadro che successivamente, in entrambe le pareti, venne inciso e scavato per una profondità di circa cm. 33 a sud e cm. 43 a nord. Il fondo di questi fori è rustico\" (English parallel, same page: 'The eastern one is in line with the edge of the rock floor and the other is 23 centimetres further west. At a certain height from the floor two horizontal lines about 30 centimetres apart form a small square with the others. Moreover, higher up can be seen another identical square which subsequently, in both the walls, was incised and excavated to a depth of about 33 cms. to the south and 43 cms. to the north. The bottom of these holes is rough'); Osservazioni n.20 (p.109-110, English col.): 'the two holes existing in the wall of the crypt' ... 'the holes... have a different depth' ... rejected air-channel theory requires depth 'at least 5 metres' ('si pensi ad un minimo di 5 metri')",
   "original_units": "centimeters/meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "MISSED IN PRIOR PASS. Full layout now captured, richer than the isolated p.59 depth figures alone: on the north and south crypt walls, two vertical red guide-lines run the full wall height - the east line aligned with the rock-floor edge, the west line offset 23 cm further west. At a certain height above the floor, two horizontal red lines about 30 cm apart cross these verticals to form a small marked-out rectangle/square (riquadro); a second, higher, identical rectangle was marked the same way and THIS one was actually incised/excavated into the wall, to a depth of about 33 cm on the south wall and 43 cm on the north wall. Bottom of the excavated holes is roughly finished ('rustico'). M&R's own hypothesis (Osservazioni n.20, pp.109-110): the holes held a wooden cross-beam (moved from the deeper north hole to the south one) supporting a light mat/curtain partition dividing the crypt into a limestone-paved western two-thirds and a rock-floored eastern third (see companion record 'crypt_C_floor_paving_extent_fraction'). They explicitly reject Perring/Petrie/Borchardt's scaffolding-beam and 'symbolic air-channel' theories; the air-channel theory is rejected partly because such a channel would need to be 'at least 5 metres' deep through the rock to reach the exterior - this 5 m figure is a REJECTED-HYPOTHESIS estimate, not a measured value. Metric values: west-line offset 0.23 m; horizontal-line spacing ~0.30 m; excavated hole depth south 0.33 m, north 0.43 m.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "57",
   "plate": "TAV. 10",
   "feature": "sarcophagus_pit_granite_infill_blocks_surface_holes",
   "original_value": "\"alcuni presentano sulla faccia superiore dei fori rotondi di piccola profondità e del diametro di circa 10 centimetri\"",
   "original_units": "centimeters",
   "metric_conversion_m": "diameter 0.10; depth NOT REPORTED (only 'piccola' = small)",
   "confidence": "medium",
   "notes": "MISSED IN PRIOR PASS. Refers to the large granite blocks that were re-mortared into the gap between the sarcophagus and the surrounding rock-cut pit walls (same pit described in existing record 'sarcophagus_coffer_base_block_thickness'); some of these granite infill blocks show round holes of small (unquantified) depth and about 10 cm diameter on their upper face. Function not stated by M&R on this page. Exact depth is NOT REPORTED - only qualified as 'piccola' (small).",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "55",
   "plate": "TAV. 7",
   "feature": "passage_G_rock_overburden_thickness_estimate",
   "original_value": "\"pensiamo che esso non doveva essere minore dei m. 1.20 del dislivello esistente fra soffitto del corridoio e cortile perimetrale, a cui vanno aggiunti almeno 2-3 metri di nucleo roccioso\"",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "MISSED IN PRIOR PASS. M&R's own INFERENCE (not a direct measurement - 'pensiamo che', 'we think') for the minimum thickness of solid rock overlying the rock-cut passage (G) between the trench/breccia point and the crypt: at minimum the 1.20 m level-difference between the corridor's ceiling and the surrounding courtyard pavement, PLUS at least 2-3 m of additional rocky core/nucleus above that. Given in the context of explaining why M&R believe it was economical to tunnel (G) as a rock-cut gallery rather than build it in an open trench like (D)/(S)/(L)/(O). Components: dislivello soffitto-cortile >= 1.20 m; nucleo roccioso aggiuntivo >= 2-3 m. Total minimum overburden implied: roughly 3.20-4.20 m, but this total is NOT stated explicitly by M&R and should not be presented as their own summed figure - components transcribed separately per instructions.",
   "row": "upper_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "61; Osservazioni n.23 (p.113-114)",
   "plate": "TAV. 8 / TAV. 9",
   "feature": "connecting_corridoietto_shaft_X_between_O_and_A",
   "original_value": "p.61: \"Il Caviglia... procedendo nel suo lavoro oltre la saracinesca, giunto a poco più di 5 metri a sud di essa, si accorse che il pavimento del passaggio orizzontale non era formato da roccia... ma da piccoli blocchi saldamente murati. Toltili, pervenne ad una breve fossa nel pavimento di (O)... Dalla fossa parte verso nord un corridoietto inclinato (X) che passa sotto (O) e diventa ben presto un pozzo verticale sbucante nel soffitto del corridoio ascendente inferiore (A). Le pareti del pozzo sono ben lavorate tranne che nella parte bassa, praticata in rottura ed assai rustica.\" Osservazioni n.23 (p.113, English): 'the short corridor (X), whose opening into (O) was found closed with solid masonry'; 'the course of the tunnel is parallel and very close to the corridor (A)... a useless doubling of the southern part of the latter'; 'The hole at the lower end of (X)... was perhaps made to facilitate ventilation during the work'",
   "original_units": "meters (position); descriptive (structure)",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "MISSED IN PRIOR PASS - this connecting sub-passage (X) between corridor (O) and the ceiling of ascending corridor (A) is NOT present anywhere in the prior 33-record extraction. Position: opening/pit found by Caviglia just over 5 m south of the upper portcullis (S), in the floor of corridor (O) - likely the same trench feature elsewhere called (T) (cf. existing record 'belzoni_distance_L_to_trench_T': Belzoni found this trench ~7 m beyond L, a nearby but not necessarily identical reference point/measurement). From that pit, an inclined corridoietto (X) runs north, passing under (O), becoming a vertical shaft opening into the ceiling of (A). M&R's own theory (Osservazioni n.23): X was an abandoned construction error - workers tried to excavate (A) simultaneously from (P) southward and from (O)/trench northward, miscalculated so the two headings would not meet, abandoned (X), and continued (A) from (P) only; a small hole/pozzetto at the lower end of X may have served for ventilation during work; X's south opening (into O) and its connection hole into (A)'s ceiling were both later sealed with masonry (traces of mortar noted on A's ceiling at the junction). NO explicit LENGTH, WIDTH, or HEIGHT is given anywhere for corridoietto/shaft (X) itself - NOT REPORTED. This is a genuinely new named sub-feature for the physics model (a disused, sealed, near-parallel twin of the lower part of corridor A).",
   "row": "connecting"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "59",
   "plate": "TAV. 10",
   "feature": "crypt_C_nucleus_stepped_rock_level_above_courtyard",
   "original_value": "\"Questo ci permette di sapere quale fosse il livello della roccia gradinata in un punto interno del quadrato di base della piramide. In corrispondenza della cripta esso raggiungeva almeno l'altezza di 3 metri sul piano, fissato come zero, del cortile perimetrale.\" (English parallel: 'This permits us to know what the level of the stepped rock was at a point inside the pyramid's square base. Near the crypt it reached the height of at least 3 metres above the level (considered as zero) of the surrounding courtyard.')",
   "original_units": "meters",
   "metric_conversion_m": 3.0,
   "confidence": "high",
   "notes": "MISSED IN PRIOR PASS. Distinct from other '3 metres' figures elsewhere in the text (e.g. the Belzoni-to-trench-T distance, or the robbers' trial-dig depth): this is the level of the pyramid's internal stepped rock nucleus (the terraced rock core exposed by the crypt excavation) measured near the crypt, stated as reaching AT LEAST 3 m above the courtyard-pavement zero datum. Given by M&R as a way to calibrate internal rock-nucleus step levels since the crypt walls are cut directly into this rock. Useful as an independent overburden/rock-level data point for the crypt area, complementary to the passage-(G) overburden estimate (see record 'passage_G_rock_overburden_thickness_estimate').",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.1 (Testo)",
   "year": 1966,
   "volume": "5,1 (Testo)",
   "page": "Osservazioni n.20 (p.110)",
   "plate": "TAV. 10",
   "feature": "crypt_C_floor_paving_extent_fraction",
   "original_value": "\"si osservi quanto grande sia la lunghezza della camera funeraria rispetto alla sua larghezza e si noti che i due terzi occidentali della cripta stessa sono lastricati, mentre il rimanente pavimento è formato dalla viva roccia\" (English, same note: 'the two western thirds of the crypt itself are paved, while the remainder of the floor consists of living rock')",
   "original_units": "fraction (no meters given)",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "MISSED IN PRIOR PASS. Supplementary geometric detail for the crypt (C) floor, given only as a fraction (western two-thirds limestone-paved, eastern third bare/living rock), no absolute meters stated on this page. Complements existing record 'belzoni_chamber_floor_slab_thickness' (35-40 cm paving thickness) and the main-text note that the rock is 30-40 cm lower on the east side. Used by M&R as part of their argument (with the two incised wall-holes, see separate record) for a proposed light partition dividing the crypt into a western funerary chamber and an eastern antechamber/serdab.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 7 / TAV. 8 (cross-confirmed both plates)",
   "feature": "corridor_D_upper_descending_total_length",
   "original_value": "Ceiling-line (ceiling/roofline of corridor D) cumulative dimension chain from entrance threshold down-slope, TAV.7: 1.65, 2.10, 2.99, 4.70, 6.24, 8.62, 11.09, 13.42, 15.18, 18.20, 20.32, 22.41, 25.91, 27.83, 29.93 (m) - terminal/total value 29.93. Floor-line (parallel lower-edge) cumulative chain, TAV.7: 1.85, 2.84, 4.12, 6.05, 8.02, 10.62, 13.16, 15.32, 17.67, 19.82, 22.36, 24.93, 27.25, 31.70 (m) - terminal/total value 31.70. TAV.8 independently labels the same corridor 'all'architrave del locale saracinesca 31.70' (to the architrave of the portcullis chamber = 31.70 m), matching the TAV.7 floor-line total exactly. Slope angle labeled on both plates: 26deg30'.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Corridor D = the upper (original, north-face) descending entrance passage, from the casing/threshold (soglia) down to the point it becomes horizontal at the upper portcullis housing (S) / chamber L. Two parallel cumulative dimension chains run along the drawing (one along the roofline/ceiling edge of the masonry-lined corridor, one along the floor edge), reflecting that ceiling-block and floor-block joints do not align. Ceiling-line total to the transition = 29.93 m; floor-line total to the same transition (portcullis-chamber architrave) = 31.70 m, independently corroborated on TAV.8. Individual block-to-block intervals (see original_value) may be useful directly for a segmented acoustic/physics model rather than collapsing to one 'D length' figure. Entrance height above courtyard pavement (external, not corridor length) is separately labeled 11.54 m on TAV.7; the pyramid-face/casing angle is labeled '53deg10\\' (Petrie e da diverse misure su blocchi in alto)' on both TAV.7 and TAV.8.",
   "row": "upper_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 7",
   "feature": "corridor_O_horizontal_segment_lengths",
   "original_value": "Ceiling-line (upper edge) sub-segments, west to east toward D: 3.51, 6.20, 8.61 (m) = 18.32 m summed. Floor-line (lower edge) sub-segments over a shorter span of the same corridor: 2.71, 7.01 (m) = 9.72 m summed (does not cover the full O span - floor-line dimensioning stops short of the west end near 'roccia intonacata/roccia senza intonaco'). A separate value '4.30' and '5.36' label the natural-rock floor patch at the west end (not corridor length).",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "Corridor O = the horizontal masonry-built passage immediately west of the small portcullis-adjacent chamber (S)/(L), continuing toward the Arab robbers' breach ('breccia araba') where the original passage's westward continuation is masked by later intrusion. Ceiling-line 3-segment sum (18.32 m) is the more complete figure; floor-line 2-segment figure (9.72 m) plausibly covers only part of the same run (block joints on floor vs ceiling do not coincide - same convention as corridor D). TAV.9's 'fig.9 Pianta del corridoio superiore' repeats 8.61 and 2.71 for O, plus a new figure 11.73 m whose exact span (O alone, or O+T combined) was NOT resolved with confidence at the image resolution reviewed - flagged for follow-up, not asserted here. Total O length from S-chamber to the west robbers'-breach boundary is NOT explicitly stated as a single summed figure by M&R on the plate; 18.32 m (ceiling line) is the best supported approximation.",
   "row": "upper_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 7",
   "feature": "corridor_L_and_portcullis_S_housing_segment_lengths",
   "original_value": "L (ceiling line, between O and the S housing): 8.07 m. Adjacent value inside/beside the S housing box: 8.46 m. S housing (upper portcullis slot) overall span above the slot: 1.05 m, subdivided into a partial value '.39' (m) plus a small uncertain figure (illegible at reviewed resolution). Two short connector segments immediately south/downslope of S, before reaching D: 0.72 m and 0.30 m.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "L = short horizontal corridor segment between O and the upper portcullis housing S; S = the housing/slot for the upper granite portcullis (saracinesca), drawn as a dashed-outline vertical rectangle cut into the masonry. Precise attribution of 'which side of S is toward the entrance vs toward the crypt' (i.e., whether L is 'the corridor leading to the portcullis' or 'beyond the portcullis' in the sense the requester used) could NOT be confirmed with certainty from the plate alone - the physical order along the passage, west to east, reads O - L - S - [D upslope to entrance]; cross-check against M&R's own text volume (Testo, not this Tavole file) is recommended before final labeling. Do not conflate this upper S/portcullis with the separate granite saracinesca M documented in the 'portcullis_M_saracinesca_dimensions' record below (TAV.9), which appears to be a second, distinct portcullis associated with the lower/subsidiary passage system.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 10 (also referenced on TAV. 9)",
   "feature": "gallery_G_total_length_from_crypt",
   "original_value": "'dalla cripta 39.35' (from the crypt = 39.35 m) - labeled at both ends of the same dimension line on TAV.10 fig.1 (Sezione S-N), and independently repeated as 'dalla cripta 39.35' on TAV.9. Partial cumulative chain along part of the run (TAV.10 fig.1, west portion near letter A/W toward X): 2.15, 3.15, 4.36, 5.73, 7.04, 7.83, 9.39, 10.06, 11.27, 12.27 (m), with a lateral offset '1.25' m noted at a bend, and a wall-height figure '1.80' m near the east end (point X). Wall construction note: 'pareti a blocchi di calcare molto irregolari, generalmente su 2/3 corsi' (walls of very irregular limestone blocks, generally 2-3 courses); 'pavimento in leggera pendenza verso S' (floor lightly sloping toward S/south).",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "G = the rock-cut gallery connecting the crypt (C) to the trench/breccia point (T) where the ascending/robbers' system (T-X-A) begins. Total length 39.35 m from the crypt is stated twice, on two different plates (TAV.9 and TAV.10), and is the most solidly corroborated single corridor total in this extraction pass. The 10-value partial chain (2.15 through 12.27) does not by itself sum to 39.35 - it covers only part of the run near the west/A-W end; the remainder of the chain toward the crypt was not fully re-transcribed at the resolution reviewed (time-boxed - flagged for a follow-up close pass on TAV.10 fig.1 if higher precision on intermediate G joints is needed). Passage cross-section note found in the companion text volume (see existing record 'passage_G_rock_overburden_thickness_estimate' in mr-plates-khafre.json, TAV.7 p.55) gives M&R's own inference of >=1.20 m ceiling-to-courtyard difference plus >=2-3 m rock nucleus above G - consistent with G being a fully rock-cut, roofed-over gallery rather than an open masonry-lined trench like D/S/L/O.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 9",
   "feature": "trench_T_to_ascending_A_projected_lengths_and_slopes",
   "original_value": "'in proiezione 8.98' (in [horizontal] projection = 8.98 m) and, further along the same bottom strip, 'in proiezione 22.40' (= 22.40 m), labelling the horizontal-projection lengths of two successive sloped tunnel segments between trench T and corridor A. Slope angles labeled at intervals along the same irregular passage: 22deg10'/22deg30', 24deg30'/25deg, 22deg40' ('pro nel soffitto'), 21deg30'. Captions: 'inizio del corridoio discendente T-A' (start of the descending corridor T-A) and 'inizio del soffitto del corridoio discendente A' (start of the ceiling of the descending [passage toward] A).",
   "original_units": "meters (lengths); degrees-minutes (slopes)",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "This is the irregular, robber-cut/trial connecting passage between trench T (where Caviglia/earlier explorers broke in) and the point where it meets the true ascending corridor A - distinct from a clean single-angle M&R construction corridor, hence multiple slightly different slope readings along its length rather than one angle. Both projected lengths (8.98 m, 22.40 m) are explicitly labeled 'in proiezione' (horizontal projection), i.e. NOT the true slope-length of those segments - true slope length would be projection / cos(slope angle), not computed here since M&R do not state it directly and the angle applying to each specific projected segment was not disambiguated with confidence at the resolution reviewed. Do not treat 22.40 m as A's own total corridor length; it is a projected sub-segment of the T-to-A connector.",
   "row": "connecting"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 8 / TAV. 9 (cross-confirmed both plates)",
   "feature": "corridor_P_lower_horizontal_total_length",
   "original_value": "'dall'inizio del corridoio ascendente 15.75' (from the start of the ascending corridor = 15.75 m), dimension line spanning from the 'camera inferiore' / 'ala camera inferiore' area to the foot of the ascending diagonal at point M (portcullis M), TAV.8 fig.6 'Particolare dello sbocco'. Nearby, on TAV.9, related figures '15.70' and 'incastro saracinesca' (portcullis housing recess) and a separate '15.35' appear along the same general run.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "P = the lower horizontal corridor of the subsidiary/lower entrance system, running from near the 'camera inferiore' (lower chamber, labelled N elsewhere) east to the foot of the ascending corridor and the lower granite portcullis M. 15.75 m is clearly labeled with an explicit dimension line and caption on TAV.8 and is the best-supported single total for P. The nearby '15.70' and '15.35' figures on TAV.9 were not fully disambiguated (possibly measured to slightly different reference points - e.g. to the portcullis housing recess ('incastro saracinesca') vs to the external threshold ('soglia esterna') - flagged, not asserted as separate measurements with confidence).",
   "row": "lower_horizontal"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 8 / TAV. 9",
   "feature": "corridor_I_lower_descending_total_length_and_site_benchmarks",
   "original_value": "'a 34.15 alla soglia esterna' (at 34.15 [m] to the external threshold), labeled along the lower descending corridor near the portcullis-M area on TAV.9. Slope angle labeled 21deg40' on TAV.8 fig.2 'Pianta del corridoio inferiore'. Site benchmark (not corridor length): 'dal taglio della collina a nord = 59.00' (from the north hill-cut = 59.00 m), TAV.8 fig.4 'Sbocco del corridoio inferiore, pianta'.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "medium",
   "notes": "I = the lower/subsidiary descending corridor, running from the outer entrance cut into the courtyard pavement down to the M portcullis / P junction. 34.15 m (to the external threshold) is the best candidate for I's total length but the exact start-point of the measurement (M portcullis vs some other datum) was not confirmed with full certainty at the resolution reviewed - treat as approximate/medium confidence pending a closer TAV.9 pass. The 59.00 m 'dal taglio della collina a nord' figure is a site-survey benchmark distance (to a hill-cut reference point used across the whole M&R survey grid for this complex), not a corridor dimension - included here only because it appears on the same plate and could be needed to reconcile absolute site coordinates.",
   "row": "lower_entrance"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 9",
   "feature": "portcullis_M_saracinesca_dimensions",
   "original_value": "'La larghezza della saracinesca era compresa fra m. 1.10 e 1.15, la sua altezza fra m. 1.33 e m. 1.60 e lo spessore era di circa 0.31' (The width of the portcullis slab was between 1.10 and 1.15 m, its height between 1.33 and 1.60 m, and its thickness was about 0.31 m). TAV.9 fig.8 'Proiezione della parete Est'.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "This is the granite portcullis (saracinesca) housed at point M, in the lower/subsidiary passage system (at the foot of the ascending corridor, on corridor P), distinct from the upper portcullis housing S documented on TAV.7 (see 'corridor_L_and_portcullis_S_housing_segment_lengths' record above - that record's S dimensions are much less certain than this M figure, which is a direct, explicit M&R quotation with a clean range for all three dimensions). Ranges (rather than single values) reflect that the slab itself is not perfectly rectangular/was measured at multiple points.",
   "row": "portcullis"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 9",
   "feature": "shaft_X_status_no_dimension",
   "original_value": "'Il volume X fu trovato pieno di muratura' (The volume X was found full of masonry). TAV.9 fig.1 'Sezione S-N guardando a W'.",
   "original_units": "descriptive only, no dimension given",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Confirms, directly from the plate drawing (independent of the existing text-volume record 'connecting_corridoietto_shaft_X_between_O_and_A' in mr-plates-khafre.json), that shaft/corridoietto X - the abandoned construction connector between corridor O and the ceiling of ascending corridor A - was found entirely backfilled/sealed with masonry. NO length, width, height, or depth figure for X is given anywhere on TAV.9 or the other plates reviewed - DRAWING ONLY, dimensions NOT REPORTED.",
   "row": "connecting"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 9",
   "feature": "connector_R_and_chamber_N_partial_dimensions",
   "original_value": "Chamber N (lower/subsidiary chamber, 'appartamento inferiore'), TAV.9 fig.2 'Pianta dell'appartamento inferiore': width figures 3.10 m and 3.12 m (N chamber, two points), 2.10 m, 1.03 m; connector R: 6.70 m (a diagonal/offset dimension near R), 1.18 m, 1.40 m, 1.20-1.34 m range on adjoining sections. TAV.10 fig.13 'Particolare R' shows a small stepped rock detail with cm-scale figures (4, 25, 18 approx. - not confidently resolved as meters or cm at reviewed resolution).",
   "original_units": "meters (chamber N); uncertain scale for fig.13 'Particolare R' (possibly centimeters)",
   "metric_conversion_m": null,
   "confidence": "low",
   "notes": "R appears to be a short connecting duct/step between the lower chamber N and corridor P, not a long corridor - no total 'R length' comparable to D/G/P/I was identified. Chamber N's overall footprint could not be resolved into a single confident length x width statement at the image resolution reviewed in this pass (multiple partial dims scattered across fig.2, fig.6 'Sezione YY', and fig.7 'Sezione XX' on TAV.9); 3.10 m recurs most often and is the best candidate for N's width. FLAGGED for a dedicated high-resolution close pass on TAV.9's fig.2/6/7 cluster and TAV.10's fig.13/14/15 'Particolare R/S/T' cluster if precise chamber-N and connector-R geometry is required - not completed here given time constraints.",
   "row": "subsidiary_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 10",
   "feature": "crypt_C_height_estimates_by_surveyor",
   "original_value": "'Altezze: Perring 5.97 - 6.83; Petrie 5.24 - 6.21; Vandier 5.24 - 6.84' (m), TAV.10 fig.1 'Sezione S-N guardando a W', comparison box beside the crypt's north gable-roof section.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "A direct comparison table M&R drew onto the plate itself, giving three earlier surveyors' (Perring, Petrie, Vandier) differing height-range estimates for the crypt (C) chamber, evidently reflecting disagreement over which reference points (floor level, gable apex, etc.) to measure between. Useful as an independent cross-check band for the crypt's internal height in a physics/acoustic model - use the overlap zone (~5.97-6.21 m) as the most mutually consistent range if a single value is needed, but note M&R present these as three distinct historical estimates, not a resolved consensus figure of their own.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 10",
   "feature": "crypt_C_plan_width_and_sarcophagus_dimensions",
   "original_value": "Crypt (C) overall plan width, recurring at both ends of the plan (fig.2 'Pianta'): 4.97 m and 4.99 m. Sarcophagus (fig.9/fig.10/fig.11 detail cluster, top right of plate): 2.63 m (length) x 2.15/2.25 m and 1.07 m (width/height details across the coffer/lid views).",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Crypt plan width ~4.97-4.99 m corroborates the text-volume record already captured in mr-plates-khafre.json ('sarcophagus_pit_granite_infill_blocks_surface_holes' etc.) and the separately-documented floor-paving fraction and incised wall-hole records for the same chamber. Sarcophagus figures (2.63 m length, ~1.07 m depth) are drawing-confirmed and consistent with standard literature values for Khafre's sarcophagus; the crypt's full length (north-south) was not confidently re-derived from the plan view in this pass - only the recurring width figure is reported here with high confidence.",
   "row": "burial_chamber"
  },
  {
   "source": "Maragioglio_Rinaldi_1966",
   "author": "Maragioglio, Vito; Rinaldi, Celeste Ambrogio",
   "publication": "L'Architettura delle Piramidi Menfite, Parte V, Vol. 5.2 (Tavole) - Le Piramidi di Zedefra e di Chefren",
   "year": 1966,
   "volume": "5,2 (Tavole)",
   "page": "plate drawing, not text",
   "plate": "TAV. 10",
   "feature": "breccia_robbers_breach_position_from_crypt_north_wall",
   "original_value": "'20.60' and '19.81 dalla parete N della cripta' (from the north wall of the crypt), TAV.10, bottom strip near 'breccia nel rivestimento della parete' / 'Sezione NN' detail.",
   "original_units": "meters",
   "metric_conversion_m": null,
   "confidence": "high",
   "notes": "Marks two reference points (likely the near and far edges of the robbers' breach in the casing, or two independent measurement passes) along corridor G, measured back from the crypt's north wall. Consistent with, and a useful independent cross-check on, the 39.35 m G-corridor total (from the crypt to the far/T end) documented in the 'gallery_G_total_length_from_crypt' record above - the breach sits roughly 19-20 m into the 39.35 m run, i.e. a little past its midpoint.",
   "row": "burial_chamber"
  }
 ]
}