---
slug: the-evening-you-could-afford
passed: 2026-10-18
by: the assay line (research/assay-line/queue-1018/), Codex fixer directed by claude-assaying-boyle-1014; source record by Codex, checked by Codex; independently reviewed and repaired by Codex, 2026-10-18
checked: 93
confirmed: 68
wrong: 25
unverifiable: 0
observed: 0
stale: 0
---

This is the queue-1018 tier A decide-and-fix pass for the-evening-you-could-afford, using the layer bytes read at 03d50827e7. All 25 triage entries were decided and the JSON validated before layer edits. The 18 WRONG entries represent ten distinct errors; seven MINOR entries received small wording fixes without public correction lines. MINOR entries are included in the wrong count for this record. The 68 CONFIRMED source checks below are carried forward from N2-codex.md with their stated limits; the fixer re-read the evidence for every triage item. This record covers that work list and the confirmed source checks, rather than certifying the separate UNVERIFIABLE and OBSERVED entries in N2.

## Claims

- MINOR | X1 (panel-is-appendix): describing the experiment that produced its oldest number. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed p. 52 (PDF page 27), including its page image: "Open fire" and "Neolithic lamp" precede "Babylonian lamp". The appendix, pp. 64-65, gives the Babylonian oil price and wage, whereas the earlier estimates use foraging assumptions. Cheap MINOR fix: qualify Babylon as the oldest price in this series based on quoted market prices and wages. The quoted appendix passage itself is accurate and will remain unchanged. Decision: fix. Error: oldest-market-price. Evidence re-read: true.
- WRONG | X2 (every-reader-before-gas): every reader before the gas mantle lived in it. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.1, printed p. 32 (PDF page 7): "William Wallace’s 500-candlepower arc lights" appear in 1876 before the "Welsbach gas mantle" in the 1880s. Table 1.2, p. 35, also lists an "Argand burner" giving 16.0 candle-hours per hour in the 1855 experiment. Readers before the mantle did not all use one candle. Fix by limiting the sentence to reading by a single tallow candle. Decision: fix. Error: all-readers-single-candle. Evidence re-read: true.
- WRONG | X3 (frontier-caption): The frontier of the day: the cheapest light available at each date. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed pp. 52-53 (PDF pages 27-28), and inspected the p. 52 image. Its 1875-85 kerosene labour price is "0.2253", below town gas at "0.326" and the selected 1883 Edison value 0.750239. The local ERAS array in research/light-labour-price/run.mjs selects those dearer rows rather than computing minima. Fix all claims that these selected technologies are the cheapest available, including the budget description and modern product labels; keep the supported prices and budget arithmetic. Decision: fix. Error: selected-prices-called-frontier. Evidence re-read: true.
- WRONG | X4 (series-table): The frontier of the day: the cheapest light available at each date. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed pp. 52-53 (PDF pages 27-28), and inspected the p. 52 image. Its 1875-85 kerosene labour price is "0.2253", below town gas at "0.326" and the selected 1883 Edison value 0.750239. The local ERAS array in research/light-labour-price/run.mjs selects those dearer rows rather than computing minima. Fix all claims that these selected technologies are the cheapest available, including the budget description and modern product labels; keep the supported prices and budget arithmetic. Decision: fix. Error: selected-prices-called-frontier. Evidence re-read: true.
- WRONG | X5 (lamp-count): That last file holds 6,573 lamps. | git show 1fde322cb4:research/light-labour-price/results.json | Read research/light-labour-price/results.json at modern.population: "totalRecords": 8659 and "bandRecords": 6573. Independently parsed data/doe-ccd-gsl-integrated-leds.csv: 8,659 records, with 6,573 having 400 to 1,600 lumens. Read index.html setting i-lamps from D.modern.lampsInBand. Fix the prose and readout to distinguish total records from the selected band, whose median is reported. Decision: fix. Error: lamp-file-count. Evidence re-read: true.
- WRONG | X6 (budget-yardstick): spend one per cent of them on light at that era's frontier price | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed pp. 52-53 (PDF pages 27-28), and inspected the p. 52 image. Its 1875-85 kerosene labour price is "0.2253", below town gas at "0.326" and the selected 1883 Edison value 0.750239. The local ERAS array in research/light-labour-price/run.mjs selects those dearer rows rather than computing minima. Fix all claims that these selected technologies are the cheapest available, including the budget description and modern product labels; keep the supported prices and budget arithmetic. Decision: fix. Error: selected-prices-called-frontier. Evidence re-read: true.
- WRONG | X7 (gas-in-price-index): it does not appear in any price index. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, printed p. 48 (PDF page 23): Nordhaus says he constructs a "frontier price index". Table 1.4 note 6, printed p. 47, says the CPI for "gas and electric fuels" was used for 1940-92. Thus the unqualified claim that the change appears in no price index is false. Replace it with the narrower finding that conventional indexes miss the full improvement in the price of lighting services. Decision: fix. Error: gas-absent-from-all-indexes. Evidence re-read: true.
- WRONG | X8 (1800-eyes): they read by one candle and ruined their eyes | https://www.aao.org/eye-health/tips-prevention/common-eye-vision-myths-facts | Re-read the American Academy of Ophthalmology article through its indexed primary-source page at https://aao.org/eye-health/tips-prevention/five-vision-myths, under "Reading in dim light is harmful to your eyes": "It does not harm your eyes to read in dim light." The supplied URL returned 403, but the official alternate URL exposes the same article. It distinguishes fatigue from damage. Delete the claim that candle readers ruined their eyes; the correction will cite this distinction without diagnosing historical readers. Decision: fix. Error: dim-reading-damages-eyes. Evidence re-read: true.
- WRONG | X9 (unstated-constants): Three constants the paper never states, recovered | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.3 note c, printed p. 36: "generates 13 lumens for 7 hours". Printed p. 48 explicitly says "approximately twenty-four cents per kilowatt-hour". The page itself also says thirteen is stated in a footnote. These constants can be recovered or cross-checked but cannot all be called unstated. Fix the heading, check summary, dek, and verifier wording; retain the supported recovery of the implicit Babylonian month and leave source quotations unchanged. Decision: fix. Error: constants-all-unstated. Evidence re-read: true.
- MINOR | X10 (babylon-price-inputs): The oldest price in the series | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed p. 52 (PDF page 27), including its page image: "Open fire" and "Neolithic lamp" precede "Babylonian lamp". The appendix, pp. 64-65, gives the Babylonian oil price and wage, whereas the earlier estimates use foraging assumptions. Cheap MINOR fix: qualify Babylon as the oldest price in this series based on quoted market prices and wages. The quoted appendix passage itself is accurate and will remain unchanged. Decision: fix. Error: oldest-market-price. Evidence re-read: true.
- WRONG | X11 (flame-efficacy-audit): Mills’s eight kerosene wick lamps | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | Read the downloaded Mills (2003) PDF, printed p. 4, Experimental Approach and Table 1: "Fuel-use measurements for four kerosene lamps" and "Two trials were conducted for each lamp". Its note says light output for trials 3-5 and 3-6 is estimated. The eight columns are trials on four lamps. The endpoints 935 and 1,914 lumen-hours/litre convert to about 0.096 and 0.197 lm/W only with the stated 0.80 kg/L and 43.8 MJ/kg assumptions. Fix the lamp count, describe the range as derived from trials, and remove the unsupported claim that these are the only published open-flame measurements. Decision: fix. Error: mills-lamps-versus-trials. Evidence re-read: true.
- WRONG | X12 (mills-eight-lamps-only): Mills’s eight kerosene wick lamps | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | Read the downloaded Mills (2003) PDF, printed p. 4, Experimental Approach and Table 1: "Fuel-use measurements for four kerosene lamps" and "Two trials were conducted for each lamp". Its note says light output for trials 3-5 and 3-6 is estimated. The eight columns are trials on four lamps. The endpoints 935 and 1,914 lumen-hours/litre convert to about 0.096 and 0.197 lm/W only with the stated 0.80 kg/L and 43.8 MJ/kg assumptions. Fix the lamp count, describe the range as derived from trials, and remove the unsupported claim that these are the only published open-flame measurements. Decision: fix. Error: mills-lamps-versus-trials. Evidence re-read: true.
- WRONG | X13 (check-summary): Three constants the paper never states were recovered | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.3 note c, printed p. 36: "generates 13 lumens for 7 hours". Printed p. 48 explicitly says "approximately twenty-four cents per kilowatt-hour". The page itself also says thirteen is stated in a footnote. These constants can be recovered or cross-checked but cannot all be called unstated. Fix the heading, check summary, dek, and verifier wording; retain the supported recovery of the implicit Babylonian month and leave source quotations unchanged. Decision: fix. Error: constants-all-unstated. Evidence re-read: true.
- MINOR | X14 (babylon-oldest-number): The oldest number | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed p. 52 (PDF page 27), including its page image: "Open fire" and "Neolithic lamp" precede "Babylonian lamp". The appendix, pp. 64-65, gives the Babylonian oil price and wage, whereas the earlier estimates use foraging assumptions. Cheap MINOR fix: qualify Babylon as the oldest price in this series based on quoted market prices and wages. The quoted appendix passage itself is accurate and will remain unchanged. Decision: fix. Error: oldest-market-price. Evidence re-read: true.
- MINOR | X15 (sesame-experiment): a supermarket brand of cold-pressed sesame oil | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER appendix, printed pp. 64-65 (PDF pages 39-40): it names "100 percent Hunza pure cold-pressed sesame oil" and a "Minolta TL-1 illuminance meter" (the extracted text splits TL-1). It does not identify Hunza as a supermarket brand. Cheap MINOR fix: remove the unsupported retail description in the paraphrase, preserving the brand, cold-pressed description, experiment details, and the verbatim canvas quotation. Decision: fix. Error: sesame-oil-retail-description. Evidence re-read: true.
- MINOR | X16 (minolta-meter): a supermarket brand of cold-pressed sesame oil | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER appendix, printed pp. 64-65 (PDF pages 39-40): it names "100 percent Hunza pure cold-pressed sesame oil" and a "Minolta TL-1 illuminance meter" (the extracted text splits TL-1). It does not identify Hunza as a supermarket brand. Cheap MINOR fix: remove the unsupported retail description in the paraphrase, preserving the brand, cold-pressed description, experiment details, and the verbatim canvas quotation. Decision: fix. Error: sesame-oil-retail-description. Evidence re-read: true.
- WRONG | X17 (candle-efficacy-heat-anisotropy): 0.1009 lumens per watt, sits inside the band you get from NIST's measured candle heat-release of 77 watts once you correct for the anisotropy that Mills measured | git show 1fde322cb4:research/light-labour-price/results.json; https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101159; http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | Read research/light-labour-price/run.mjs, results.json, constants.mjs, and verify-the-evening-you-could-afford.mjs: "nordhaus": 0.1009 is below "anisotropyCorrectedBand": [0.10607975193939562, 0.11913572140885968], computed as 4*pi*[0.65,0.73]/77. The verifier instead tests "phys.candleEfficacy.nordhaus > ab[0] * 0.9". Also re-read NIST, printed p. 277 (PDF page 13), where heat release is "calculated as 77" with uncertainty 9 W, and Mills, pp. 4 and 6, whose directional measurements are for kerosene lanterns. No uncertainty is propagated into this band. Nordhaus implies 13/0.1009 = 128.8404 W; the 0.163 comparison uses NIST's 77 W instead, so it does not establish which isotropy assumption Nordhaus avoided. Fix both the prose and verifier: assert the actual separation, label the calculation as an illustrative cross-source comparison, and retain only the qualified four-lamp trial comparison. Decision: fix. Error: candle-comparison-band. Evidence re-read: true.
- WRONG | X18 (eight-real-wick-lamps): the eight real wick lamps Mills tested. | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | Read the downloaded Mills (2003) PDF, printed p. 4, Experimental Approach and Table 1: "Fuel-use measurements for four kerosene lamps" and "Two trials were conducted for each lamp". Its note says light output for trials 3-5 and 3-6 is estimated. The eight columns are trials on four lamps. The endpoints 935 and 1,914 lumen-hours/litre convert to about 0.096 and 0.197 lm/W only with the stated 0.80 kg/L and 43.8 MJ/kg assumptions. Fix the lamp count, describe the range as derived from trials, and remove the unsupported claim that these are the only published open-flame measurements. Decision: fix. Error: mills-lamps-versus-trials. Evidence re-read: true.
- WRONG | X19 (frontier-fuel-definition): Every price on this page is the cost of the best available technology | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed pp. 52-53 (PDF pages 27-28), and inspected the p. 52 image. Its 1875-85 kerosene labour price is "0.2253", below town gas at "0.326" and the selected 1883 Edison value 0.750239. The local ERAS array in research/light-labour-price/run.mjs selects those dearer rows rather than computing minima. Fix all claims that these selected technologies are the cheapest available, including the budget description and modern product labels; keep the supported prices and budget arithmetic. Decision: fix. Error: selected-prices-called-frontier. Evidence re-read: true.
- WRONG | X20 (meta-dek-4): three constants the paper never states come back out of it | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.3 note c, printed p. 36: "generates 13 lumens for 7 hours". Printed p. 48 explicitly says "approximately twenty-four cents per kilowatt-hour". The page itself also says thirteen is stated in a footnote. These constants can be recovered or cross-checked but cannot all be called unstated. Fix the heading, check summary, dek, and verifier wording; retain the supported recovery of the implicit Babylonian month and leave source quotations unchanged. Decision: fix. Error: constants-all-unstated. Evidence re-read: true.
- WRONG | X21 (related-note-3): the centre is brighter than the corner by exactly three root three over two, whatever lamp you use. | git show 1fde322cb4:public/strata/the-evening-you-could-afford/index.html; research/light-labour-price/run.mjs | Read the shipped evening-model code in index.html: "return (candela * h) / Math.pow(d2, 1.5)" and "3 * Math.sqrt(3)". At h=r/sqrt(2), independent calculation gives Ecentre/Ecorner = (1+r*r/(h*h))^(3/2) = 3*sqrt(3) = 5.196152422706632. The body already prints "3√3 ≈ 5.196". The relates note and verifier comment incorrectly halve that ratio. Restore three root three in those copies. Decision: fix. Error: centre-corner-ratio-halved. Evidence re-read: true.
- WRONG | X22 (related-three-root-three-over-two): the centre is brighter than the corner by exactly three root three over two, whatever lamp you use. | git show 1fde322cb4:public/strata/the-evening-you-could-afford/index.html; research/light-labour-price/run.mjs | Read the shipped evening-model code in index.html: "return (candela * h) / Math.pow(d2, 1.5)" and "3 * Math.sqrt(3)". At h=r/sqrt(2), independent calculation gives Ecentre/Ecorner = (1+r*r/(h*h))^(3/2) = 3*sqrt(3) = 5.196152422706632. The body already prints "3√3 ≈ 5.196". The relates note and verifier comment incorrectly halve that ratio. Restore three root three in those copies. Decision: fix. Error: centre-corner-ratio-halved. Evidence re-read: true.
- MINOR | X23 (appendix-attribution): describing the experiment that produced its oldest number. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed p. 52 (PDF page 27), including its page image: "Open fire" and "Neolithic lamp" precede "Babylonian lamp". The appendix, pp. 64-65, gives the Babylonian oil price and wage, whereas the earlier estimates use foraging assumptions. Cheap MINOR fix: qualify Babylon as the oldest price in this series based on quoted market prices and wages. The quoted appendix passage itself is accurate and will remain unchanged. Decision: fix. Error: oldest-market-price. Evidence re-read: true.
- MINOR | X24 (canvas-oldest-number): describing the experiment that produced its oldest number. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | Read the downloaded NBER PDF, Table 1.6, printed p. 52 (PDF page 27), including its page image: "Open fire" and "Neolithic lamp" precede "Babylonian lamp". The appendix, pp. 64-65, gives the Babylonian oil price and wage, whereas the earlier estimates use foraging assumptions. Cheap MINOR fix: qualify Babylon as the oldest price in this series based on quoted market prices and wages. The quoted appendix passage itself is accurate and will remain unchanged. Decision: fix. Error: oldest-market-price. Evidence re-read: true.
- WRONG | X25 (chart-purchasing-power-label): (added) what an hour of work actually bought | git show 1fde322cb4:research/light-labour-price/build-page-data.mjs | Read research/light-labour-price/build-page-data.mjs, chart mapping: "trueLabour: r((hours / base[4]) * 100, 6)". The plotted series is the hours of work needed per fixed amount of light, indexed to 1800 = 100; how much light an hour buys is its reciprocal. Read the authored SVG label in index.html. Fix that label to labour cost of light, leaving the series and other supported purchasing-power calculations unchanged. Decision: fix. Error: labour-cost-labelled-purchasing-power. Evidence re-read: true.
- CONFIRMED | because lightness perception goes roughly as the cube root of luminance. | https://www.w3.org/TR/css-color-4/ | N2 source check carried forward: Entry 009 (cube-root-lightness). The rendering computes Math.pow(Math.min(1, E / 500), 1 / 3). W3C XYZ_to_Lab explicitly uses "Math.cbrt(value)" above its low-light breakpoint; the approximation is reasonable as the page labels it an illustration.
- CONFIRMED | A modern lighting standard asks for 500 lux for reading. | https://publikz.com/wp-content/uploads/2015/10/ISO_CIE_8995_1_2002_E__Character_PDF_document-1.pdf | N2 source check carried forward: Entry 014 (reading-standard). Read the PDF, category "22. Offices": "Writing, typing, reading, data" / "processing" has maintained illuminance "500". This is a workplace standard, not a physiological minimum for reading.
- CONFIRMED | Full moonlight at a temperate latitude is around 0.05 to 0.1 lux. | https://ucrisportal.univie.ac.at/de/publications/how-bright-is-moonlight/ | N2 source check carried forward: Entry 015 (moonlight-typical). The source says "typical lunar illuminance is around 0.05 to 0.1 lux at temperate latitudes during the summer". The page uses an approximate comparison; retain the summer qualification when revising it.
- CONFIRMED | In 1996 William Nordhaus published a price series for light running from the fires of Peking man to a compact fluorescent bulb, measured not in money but in labour: how many hours of work it took to buy a thousand lumen-hours. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 018 (nordhaus-publication-series). The cover names "Chapter Author: William D. Nordhaus" and "Publication Date: January 1996". Tables 1.1 and 1.6 cover Peking-man fire and the 1992 compact fluorescent, and the column heading reads "hours of work per 1,000 lumen-hours". Damaged OCR in the supplied excerpt is separately noted below.
- CONFIRMED | In 1996 William Nordhaus published a price series for light running from the fires of Peking man to a compact fluorescent bulb, measured not in money but in labour: how many hours of work it took to buy a thousand lumen-hours. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 019 (publication-year). The cover names "Chapter Author: William D. Nordhaus" and "Publication Date: January 1996". Tables 1.1 and 1.6 cover Peking-man fire and the 1992 compact fluorescent, and the column heading reads "hours of work per 1,000 lumen-hours". Damaged OCR in the supplied excerpt is separately noted below.
- CONFIRMED | The last row is not in the paper. Nordhaus stops at a first-generation compact fluorescent bulb in 1992, | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 025 (last-nordhaus-row). The frontier/summary series reaches the compact fluorescent in 1992, which is the endpoint extended here. The source also has a 1993 Coleman-lantern comparison row; the phrase must not be read as saying every observation in the whole paper ends in 1992.
- CONFIRMED | the average hourly earnings of all private employees, | https://fred.stlouisfed.org/series/CES0500000003 | N2 source check carried forward: Entry 027 (modern-wage-series). Curl over HTTP/1.1 recovered the page after the HTTP/2 request failed. Its note matches verbatim: "The Average Hourly Earnings of All Private Employees is a measure of the average hourly earnings of all private employees" and specifies a gross basis, overtime and late shifts.
- CONFIRMED | the average retail price of a kilowatt-hour, | https://fred.stlouisfed.org/series/APU000072610 | N2 source check carried forward: Entry 028 (modern-electric-series). Curl over HTTP/1.1 recovered the page. The title is "Average Price: Electricity per Kilowatt-Hour in U.S. City Average (APU000072610)". The committed observation is June 2026, 0.198 dollars/kWh.
- CONFIRMED | the lamp selected for the row above is a purchasable 850 lumen, 5.0 watt lamp at 170. | https://www.usa.lighting.philips.com/consumer/p/ultraefficient-filament-bulb-clear-60w-a19-e26-x2/046677582609/specifications | N2 source check carried forward: Entry 032 (purchasable-frontier-lamp). The manufacturer page still exposes the specification in HTML-entity-encoded JSON: "Luminous Efficacy (rated) (Nom)","value":"170"; "Luminous Flux","value":"850 lm"; "Power","value":"5". The online NOT FOUND is a false negative caused by stripping the data-bearing markup. Positive control: the same decoded-HTML search locates all three exact label/value pairs. Current wording calls it the selected lamp; this confirmation establishes the product specifications, not a market-wide minimum.
- CONFIRMED | Spermaceti candles, the good ones, were brighter per candle and far dearer per lumen, | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 040 (sperm-brightness-price). NBER Table 1.5 note a gives "0.75 candles" for tallow and "1 candle" for sperm oil; Table 1.6 gives prices "40.293" and "91.575" cents per 1000 lumen-hours. Both brightness and relative expense are supported.
- CONFIRMED | Here is why Nordhaus wrote the paper. Official price statistics tracked the price of a candle, and then the price of a gallon of kerosene, and then the price of a kilowatt-hour, as three separate goods, each with its own index, none of them linked to the others by what they were for. Measured that way, the price of light in the United States rose. Measured as the price of the thing people actually wanted, it collapsed. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 044 (official-vs-true-price). Read NBER p. 51: the traditional price rose "between three and five" in nominal terms; relative to the true price it rose "between nine hundred and sixteen hundred"; the Light II annual bias is "3.6 percent per year". These support the stated historical price gap. The separate chart-label error does not change that source quotation.
- CONFIRMED | Measured that way, the price of light in the United States rose. Measured as the price of the thing people actually wanted, it collapsed. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 045 (official-price-rise). Read NBER p. 51: the traditional price rose "between three and five" in nominal terms; relative to the true price it rose "between nine hundred and sixteen hundred"; the Light II annual bias is "3.6 percent per year". These support the stated historical price gap. The separate chart-label error does not change that source quotation.
- CONFIRMED | the traditional price has risen by a factor of between nine hundred and sixteen hundred relative to the true price | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 047 (nordhaus-price-gap-quote). Read NBER p. 51: the traditional price rose "between three and five" in nominal terms; relative to the true price it rose "between nine hundred and sixteen hundred"; the Light II annual bias is "3.6 percent per year". These support the stated historical price gap. The separate chart-label error does not change that source quotation.
- CONFIRMED | an average divergence of 3.6 per cent a year. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 048 (divergence-rate). Read NBER p. 51: the traditional price rose "between three and five" in nominal terms; relative to the true price it rose "between nine hundred and sixteen hundred"; the Light II annual bias is "3.6 percent per year". These support the stated historical price gap. The separate chart-label error does not change that source quotation.
- CONFIRMED | His conclusion follows immediately and is the reason the paper is still cited: if light is at all representative of the goods that changed in kind rather than in quantity, then measured real wage growth over two centuries, a factor of about thirteen, is badly understated. His own thought experiment puts the true factor between forty and a hundred and ninety, and he is careful to call that speculative. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 049 (real-wage-growth-thought-experiment). NBER pp. 62-63 gives conventional wage growth "a factor of 13", low-bias "40", high-bias "190", and explicitly calls the alternatives "highly speculative". The source record’s excerpt and attribution agree.
- CONFIRMED | The labour price of light is the price of light divided by the wage, and that is the whole of the paper's central table. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 052 (labour-price-identity). NBER Table 1.6 labels wages in cents/hour, light prices in cents/1000 lumen-hours and labour prices in hours/1000 lumen-hours. Division gives the stated unit and all priced rows are consistent when their rounding intervals are respected.
- CONFIRMED | The 1855 experiment table prices its light twice, per candle-hour and per thousand lumen-hours, and the ratio of the two is the conversion he was working in. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 057 (1855-dual-units). NBER Table 1.2 has both "cents per candle-hour" and "cents per 1,000 lumen-hours". Recomputing fuel expenditure before taking the ratio gives mean 12.93 and range 12.59 to 13.02 across nine rows. Table 1.3 note c explicitly supplies 13 lumens; Table 1.5 supplies one candlepower.
- CONFIRMED | He states thirteen in a footnote and uses it consistently. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 059 (thirteen-footnote). NBER Table 1.2 has both "cents per candle-hour" and "cents per 1,000 lumen-hours". Recomputing fuel expenditure before taking the ratio gives mean 12.93 and range 12.59 to 13.02 across nine rows. Table 1.3 note c explicitly supplies 13 lumens; Table 1.5 supplies one candlepower.
- CONFIRMED | The month is never given in hours. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 061 (month-not-given). Read pp. 33, 52-53 and 64-65 and searched the whole PDF text for "200 hours", "200-hour", "two hundred", and month passages. No Babylonian month in hours is specified. Positive controls: the same text finds "250 hours per month" for American farm workers, "1 shekel per month", and the unrelated "two hundred" passages. This supports the narrowly scoped negative claim.
- CONFIRMED | Elsewhere in the same table an American farm worker's month is 250 hours. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 063 (farm-worker-month). Table 1.6 note c reads "Average monthly earnings of farm workers" and "250 hours per month". Verified against the page image, including the note marker.
- CONFIRMED | approximately twenty-four cents per kilowatt-hour at the dawn of the electric age | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 065 (edison-price-quote). Electric price inversion gives 9.228*2.6=23.9928 cents/kWh in 1883. NBER p. 48 independently says "approximately twenty-four cents per kilowatt-hour at the dawn of the electric age" after quoting Edison’s price list. That sentence is Nordhaus’s calculation, not Edison’s own wording.
- CONFIRMED | The efficiency table’s note makes it one-fifth as efficient as a tallow candle, giving 0.01514 lumens per watt, which is exactly the 0.0151 printed. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 069 (neolithic-efficacy-definition). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | The labour table’s note makes it one-third as efficient as the Babylonian lamp, giving 0.0199 . | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 070 (neolithic-labour-definition). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | whose own column note says "From table 1.6". | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 072 (from-table-quote). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | the experiment table notes that the kerosene price is 1870’s. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 074 (kerosene-price-note). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | The efficiency footnote says 500. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 076 (town-gas-500-footnote). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | The half of the paper that could age is the physics, and some of the measurements that test it did not exist when it was written. | https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101159 | N2 source check carried forward: Entry 078 (later-measurements). Read NIST, Characterization of Candle Flames, November 2005. It gives net heat "43.3" kJ/g with uncertainty 0.3 and steady-state heat release "77" W with uncertainty 9. The latter is calculated from measured mass loss "0.105 g/min" and effective combustion heat, not a luminous-flux measurement. The primary document predates this audit and postdates Nordhaus.
- CONFIRMED | the net heat of combustion NIST measured for paraffin wax in 2005 (43.3), | https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101159 | N2 source check carried forward: Entry 080 (nist-net-heat). Read NIST, Characterization of Candle Flames, November 2005. It gives net heat "43.3" kJ/g with uncertainty 0.3 and steady-state heat release "77" W with uncertainty 9. The latter is calculated from measured mass loss "0.105 g/min" and effective combustion heat, not a luminous-flux measurement. The primary document predates this audit and postdates Nordhaus.
- CONFIRMED | and +9% above the published gross calorific value of beef tallow. | https://www.feedtables.com/content/tallow | N2 source check carried forward: Entry 081 (beef-tallow-energy). Recomputed 13/0.1009=128.8404 W; one-sixth pound burned in seven hours gives 0.180 g/min and 42.95 MJ/kg. Relative to NIST paraffin 43.3, the discrepancy is about 0.8%; relative to the feed table’s tallow gross energy 39.3 it is about 9%. This is a comparison to paraffin, not an independent measurement of spermaceti combustion heat.
- CONFIRMED | Nordhaus’s candle is 0.1009 and his whale-oil lamp 0.1346 . | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 084 (nordhaus-candle-whale-efficacy). NBER Table 1.3 gives sperm candle "0.1009" and whale-oil lamp "0.1346" lm/W, both within the Mills trial-derived range 0.096 to 0.197. Tallow is separately 0.0757 and is outside it. Interpret the page’s plural as the two specifically named values. NIST and IPCC comparisons independently reproduce.
- CONFIRMED | His fire assumes 5 million Btu per short ton, which is 5.82 MJ/kg . | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 087 (firewood-five-million-btu). NBER appendix states "5 million Btu per ton" and "10 pounds of firewood could be foraged, trimmed, and dried in 1 hour". With the stated short-ton convention, energy is 5.815 MJ/kg. IPCC Table 1.2 gives Wood/Wood Waste 15.6, lower 7.90 and upper 31.0 TJ/Gg, numerically MJ/kg. The labour calculation uses wood mass, not this calorific value.
- CONFIRMED | The IPCC default for wood is 15.6 with a 95 per cent range of 7.9 to 31 , so his figure sits below the lower bound. | https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_1_Ch1_Introduction.pdf | N2 source check carried forward: Entry 088 (ipcc-wood-range). NBER appendix states "5 million Btu per ton" and "10 pounds of firewood could be foraged, trimmed, and dried in 1 hour". With the stated short-ton convention, energy is 5.815 MJ/kg. IPCC Table 1.2 gives Wood/Wood Waste 15.6, lower 7.90 and upper 31.0 TJ/Gg, numerically MJ/kg. The labour calculation uses wood mass, not this calorific value.
- CONFIRMED | the labour price of a fire comes from pounds of wood foraged per hour, not from their energy. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 089 (fire-price-foraging). NBER appendix states "5 million Btu per ton" and "10 pounds of firewood could be foraged, trimmed, and dried in 1 hour". With the stated short-ton convention, energy is 5.815 MJ/kg. IPCC Table 1.2 gives Wood/Wood Waste 15.6, lower 7.90 and upper 31.0 TJ/Gg, numerically MJ/kg. The labour calculation uses wood mass, not this calorific value.
- CONFIRMED | His 28.6 lumen-hours from 60 mL at 17.5 lumen-hours per thousand Btu | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 091 (sesame-experiment-inputs). The appendix says "One-quarter cup (60 ml) burned for 17 hours" and gives "28.6 lumen-hours" and "17.5 lumen-hours per thousand Btu". The page reproduces what was printed. The raw product 0.17*10*17 is 28.9; this rounding discrepancy is handled separately in the two Babylonian reconstructions.
- CONFIRMED | It is one candlepower multiplied by 4π steradians, which assumes a candle radiates equally in every direction. | https://static.fykos.cz/problems/fykos/37/media/solution4-6.en.pdf | N2 source check carried forward: Entry 094 (isotropic-multiplication). FYKOS explicitly states "Assuming the candle emits light equally in all directions" before multiplying 1 cd by 4*pi to get 12.56 lm. This supports the explanation of that particular estimate, not a claim about every possible candle measurement.
- CONFIRMED | Mills's 2003 measurements of kerosene lanterns found total outputs of 8 to 82 lumens and, for the brightest, 9 to 10 candela horizontally against a 6.53 candela mean spherical: a factor of 0.65 to 0.73 by which the isotropic assumption overstates a flame. | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | N2 source check carried forward: Entry 097 (mills-output-anisotropy). Mills p. 6 says "total light output of 8 to 82 lumens per lantern" and "maximum of 9-10 candelas in the horizontal direction". 82/(4*pi)=6.525 mean spherical candela; divided by 9 or 10 gives 0.725 or 0.653. This is a lantern-specific correction, not a measured bare-candle correction. The unsupported exclusivity phrase was removed with X11/X12/X18; the numerical lantern measurements remain confirmed.
- CONFIRMED | An economist at Yale bought a terra-cotta lamp from a shop in Minneapolis. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 101 (yale-economist). NBER identifies Nordhaus as "professor of economics at Yale University". The appendix names "Spirits, Inc., of Minneapolis, Minnesota" and says the lamp’s "age could not be independently verified". These two passages jointly support the claim; the affiliation excerpt alone does not support the purchase.
- CONFIRMED | An economist at Yale bought a terra-cotta lamp from a shop in Minneapolis. It was sold to him as Roman and he could not check that, and he says so in print. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 102 (lamp-purchase). NBER identifies Nordhaus as "professor of economics at Yale University". The appendix names "Spirits, Inc., of Minneapolis, Minnesota" and says the lamp’s "age could not be independently verified". These two passages jointly support the claim; the affiliation excerpt alone does not support the purchase.
- CONFIRMED | Mills's measured kerosene lanterns, a technology three thousand years later, give 8 to 82. | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | N2 source check carried forward: Entry 106 (mills-later-technology). Mills’s text directly gives "8 to 82 lumens per lantern". The historical contrast is approximate: Nordhaus’s Babylonian point is 1750 BC, and his kerosene rows begin in the nineteenth century.
- CONFIRMED | NIST's 77-watt candle | https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101159 | N2 source check carried forward: Entry 108 (nist-77-watts). Read NIST, Characterization of Candle Flames, November 2005. It gives net heat "43.3" kJ/g with uncertainty 0.3 and steady-state heat release "77" W with uncertainty 9. The latter is calculated from measured mass loss "0.105 g/min" and effective combustion heat, not a luminous-flux measurement. The primary document predates this audit and postdates Nordhaus.
- CONFIRMED | The estimates the paper calls extremely rough really are rough, and this page says by how much. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 111 (extremely-rough-quote). NBER p. 38 describes the Paleolithic-lamp and open-fire estimates as "extremely rough" and singles out Silliman and modern measurements as more reliable. The quotation and its scope are correct.
- CONFIRMED | The calculation is not what people paid, and the fall in it is not a claim about how much light people actually had. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 114 (frontier-vs-actual). NBER p. 48: "I consider only the marginal cost of lighting in terms of fuel"; "Other costs, including capital, risk, labor, and environmental costs, are omitted". The model similarly uses fuel prices only; it is not an observation of household purchases.
- CONFIRMED | William D. Nordhaus, "Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting Suggests Not", in The Economics of New Goods , ed. Bresnahan and Gordon, University of Chicago Press for the NBER, 1996, pages 27 to 70. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 117 (nordhaus-reference). The NBER cover confirms author, chapter title, editors Bresnahan and Gordon, University of Chicago Press, January 1996, and "Chapter pages in book: (p. 27 - 70)". The PDF is freely retrievable, HTTP 200. The 2026 page itself cites this 1996 series thirty years later.
- CONFIRMED | Free from the NBER . | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 118 (nber-free-source). The NBER cover confirms author, chapter title, editors Bresnahan and Gordon, University of Chicago Press, January 1996, and "Chapter pages in book: (p. 27 - 70)". The PDF is freely retrievable, HTTP 200. The 2026 page itself cites this 1996 series thirty years later.
- CONFIRMED | ENERGY STAR would have been the obvious source for the last of these and no longer exists: EPA sunset the lighting specifications on 31 December 2024, | https://www.energystar.gov/sites/default/files/asset/document/ENERGY%20STAR%20Lighting%20Sunset%20Memo.pdf | N2 source check carried forward: Entry 124 (energy-star-sunset). EPA’s 13 March 2023 memo explicitly finalizes the sunset of ENERGY STAR specifications for lamps and luminaires "effective December 31, 2024". It separately preserves recessed downlights under a new specification; the context here is the old bulb dataset, not the entire ENERGY STAR program.
- CONFIRMED | For sesame-oil lamps, I purchased a Roman terra-cotta lamp supplied by | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 129 (canvas-quote-1). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | Spirits, Inc., of Minneapolis, Minnesota. It was certified as dating from | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 130 (canvas-quote-2). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | Roman times and closely resembled museum artifacts from Roman times that | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 131 (canvas-quote-3). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | I viewed, but its age could not be independently verified. This lamp was | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 132 (canvas-quote-4). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | fueled by 100 percent Hunza pure cold-pressed sesame oil with a wick | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 133 (canvas-quote-5). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | extracted from a modern candle. This proved a remarkably efficient device, | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 134 (canvas-quote-6). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | with an efficiency very close to that of a modern candle. One-quarter cup | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 135 (canvas-quote-7). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | (60 ml) burned for 17 hours with an average intensity of 0.17 foot-candles. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 136 (canvas-quote-8). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | The zone of illumination is less than a candle’s and is estimated to be | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 137 (canvas-quote-9). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | 10 lumens per foot-candle. The total illumination was therefore 28.6 | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 138 (canvas-quote-10). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | lumen-hours, for an efficiency of 17.5 lumen-hours per thousand Btu. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 139 (canvas-quote-11). Read and compared the full eleven-line canvas passage with the NBER appendix, pp. 64-65. Its words match, allowing reflowed line breaks and the source PDF page break. Each supplied quote is a contiguous segment of that passage.
- CONFIRMED | How much light one hour of work bought, from a Babylonian oil lamp in 1750 BC to an LED you can order tonight. | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 148 (meta-plain-1). The historical half is supported by NBER Table 1.6; the present lamp is supported by the Philips specification page and pinned modern inputs. The NBER excerpt alone cannot support "an LED you can order tonight".
- CONFIRMED | starlight full moon one candle, 30 cm reading standard direct sun | https://arxiv.org/pdf/1709.09558 | N2 source check carried forward: Entry 166 (lux-scale-world-values). Read the scale implementation and Haenel et al. Table 2 (arXiv:1709.09558): natural starlit night 0.6-0.9 mlux; typical summer full moon 50-100 mlux; direct sunlight 129000 lux. The scale uses 0.0008, 0.08 and 129000 respectively. The approximate one-candle marker and 500-lux office point are supported by the candle calculation and ISO, not by that table alone.
- CONFIRMED | The labour price of a tallow candle is 5.37 in the labour table and 5.387 in the summary table, | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 169 (1800-prices-primary). Checked the relevant primary tables and notes. Table 1.3 gives "one-fifth as efficient as a tallow candle"; Table 1.6 gives "one-third as efficient as the Babylonian lamp". These yield 0.01514 versus 0.0199 and labour 65.5 versus 49.8. Tables 1.4/1.6 print 5.387/5.37 with note "From table 1.6". Table 1.2 says "Price for kerosene refers to 1870." The gas note says "500 Btu per cubic foot" while Table 1.2’s derived inputs require about 550. The page retains the printed labour series while reporting these discrepancies.
- CONFIRMED | EIA’s residential series begins in 1960 and is a later vintage than the 1975 Census series Nordhaus cites, | https://www.eia.gov/totalenergy/data/browser/csv.php?tbl=T09.08 | N2 source check carried forward: Entry 170 (eia-source-beginning). Fetched EIA CSV and read annual ESRCUUS rows: "196013","2.6"; "197013","2.2"; "198013","5.4"; "199013","7.83"; "199213","8.21". Inversion and displayed percentage differences reproduce. The online PARTIAL result is formatting, not an evidentiary failure. NBER Table 1.5 cites Census S116 for designated electric rows; its 1990 row separately uses the 1992 price.
- CONFIRMED | the 1975 Census series Nordhaus cites | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 171 (census-source-citation). The provided excerpt is the summary-index footnote. For the specific electricity claim, the direct supporting passage is instead Table 1.5 note h: "Average price of residential use from U.S. Bureau of the Census (1975, S 116)." The attribution is true but the record should point to that note.
- CONFIRMED | where a modern standard asks 500 | https://publikz.com/wp-content/uploads/2015/10/ISO_CIE_8995_1_2002_E__Character_PDF_document-1.pdf | N2 source check carried forward: Entry 172 (meta-reading-500). Read the PDF, category "22. Offices": "Writing, typing, reading, data" / "processing" has maintained illuminance "500". This is a workplace standard, not a physiological minimum for reading.
- CONFIRMED | full moonlight gives 0.05 to 0.1 | https://ucrisportal.univie.ac.at/de/publications/how-bright-is-moonlight/ | N2 source check carried forward: Entry 173 (meta-moon-range). The source says "typical lunar illuminance is around 0.05 to 0.1 lux at temperate latitudes during the summer". The page uses an approximate comparison; retain the summer qualification when revising it.
- CONFIRMED | within 0.8% of NIST's paraffin | https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101159 | N2 source check carried forward: Entry 174 (meta-nist-energy). Read NIST, Characterization of Candle Flames, November 2005. It gives net heat "43.3" kJ/g with uncertainty 0.3 and steady-state heat release "77" W with uncertainty 9. The latter is calculated from measured mass loss "0.105 g/min" and effective combustion heat, not a luminous-flux measurement. The primary document predates this audit and postdates Nordhaus.
- CONFIRMED | his firewood sits below the IPCC's lower bound | https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_1_Ch1_Introduction.pdf | N2 source check carried forward: Entry 175 (meta-ipcc-bound). NBER appendix states "5 million Btu per ton" and "10 pounds of firewood could be foraged, trimmed, and dried in 1 hour". With the stated short-ton convention, energy is 5.815 MJ/kg. IPCC Table 1.2 gives Wood/Wood Waste 15.6, lower 7.90 and upper 31.0 TJ/Gg, numerically MJ/kg. The labour calculation uses wood mass, not this calorific value.
- CONFIRMED | his sperm-candle and whale-oil efficacies fit the range derived from Mills's four kerosene lamps | http://large.stanford.edu/courses/2011/ph240/machala1/docs/offgrid-lighting.pdf | N2 source check carried forward: Entry 176 (meta-mills-flames). NBER Table 1.3 gives sperm candle "0.1009" and whale-oil lamp "0.1346" lm/W, both within the Mills trial-derived range 0.096 to 0.197. Tallow is separately 0.0757 and is outside it. Interpret the page’s plural as the two specifically named values. NIST and IPCC comparisons independently reproduce. Current wording names the two compared fuels and the four-lamp trial range.
- CONFIRMED | a series that is still cited thirty years later | https://www.nber.org/system/files/chapters/c6064/c6064.pdf | N2 source check carried forward: Entry 186 (still-cited-thirty-years). The NBER cover confirms author, chapter title, editors Bresnahan and Gordon, University of Chicago Press, January 1996, and "Chapter pages in book: (p. 27 - 70)". The PDF is freely retrievable, HTTP 200. The 2026 page itself cites this 1996 series thirty years later.
- CONFIRMED | Electric row cents per kWh, recovered EIA published residential difference 1883 23.99 · · 1900 10.00 · · 1910 9.00 · · 1920 7.45 · · 1930 6.03 · · 1940 3.84 · · 1950 2.87 · · 1960 2.47 2.60 -4.9% 1970 2.10 2.20 -4.7% 1980 5.36 5.40 -0.7% 1990 8.50 7.83 +8.6% 1992 8.47 8.21 +3.1% EIA’s residential series begins in 1960 and is a later vintage than the 1975 Census series Nordhaus cites, so exact agreement is not expected. The 1883 row has no series to test it and is checked instead against Edison’s own 1883 price list, quoted in the paper. | https://www.eia.gov/totalenergy/data/browser/csv.php?tbl=T09.08 | N2 source check carried forward: Entry 187 (electricity-eia-published-values). Fetched EIA CSV and read annual ESRCUUS rows: "196013","2.6"; "197013","2.2"; "198013","5.4"; "199013","7.83"; "199213","8.21". Inversion and displayed percentage differences reproduce. The online PARTIAL result is formatting, not an evidentiary failure. NBER Table 1.5 cites Census S116 for designated electric rows; its 1990 row separately uses the 1992 price.

## Findings

- [fixed] X1 (MINOR, oldest-market-price): Qualified the Babylonian price as the oldest based on quoted market prices and wages, in the panel explanation, recovery list, closing account and model comment. MINOR: record only, no public correction line.
- [fixed] X2 (WRONG, all-readers-single-candle): Limited the sentence to readers using a single tallow candle. Review also found the generalisation in the 1800 reading-cost paragraph; that passage now describes one-candle reading as a cheaper alternative in the calculation. The dated all-readers-single-candle correction covers both copies in HTML and markdown.
- [fixed] X3 (WRONG, selected-prices-called-frontier): Relabelled the table, budget, caveat and selected modern lamp as selected technologies; corrected generator comments and documentation and regenerated results. Preserved numerical prices and source quotations. Added one dated selected-prices-called-frontier correction for all four copies.
- [fixed] X4 (WRONG, selected-prices-called-frontier): Relabelled the table, budget, caveat and selected modern lamp as selected technologies; corrected generator comments and documentation and regenerated results. Preserved numerical prices and source quotations. Added one dated selected-prices-called-frontier correction for all four copies.
- [fixed] X5 (WRONG, lamp-file-count): Separated the total 8,659 records from the 6,573 records in the 400 to 1,600 lumen band and wired the total readout to lampsCertified. Added the dated lamp-file-count correction.
- [fixed] X6 (WRONG, selected-prices-called-frontier): Relabelled the table, budget, caveat and selected modern lamp as selected technologies; corrected generator comments and documentation and regenerated results. Preserved numerical prices and source quotations. Added one dated selected-prices-called-frontier correction for all four copies.
- [fixed] X7 (WRONG, gas-absent-from-all-indexes): Replaced the claim of absence from every index with the narrower conventional-index service-price limitation. Added the dated gas-absent-from-all-indexes correction.
- [fixed] X8 (WRONG, dim-reading-damages-eyes): Deleted the claim that candle readers ruined their eyes. Added the dated dim-reading-damages-eyes correction with the official AAO source.
- [fixed] X9 (WRONG, constants-all-unstated): Changed the heading, live check summary, dek and verifier wording to recovered or cross-checked constants. Added one dated constants-all-unstated correction for the repeated error. Review restored the old heading fragment as an alias while retaining the corrected heading and new fragment.
- [fixed] X10 (MINOR, oldest-market-price): Qualified the Babylonian price as the oldest based on quoted market prices and wages, in the panel explanation, recovery list, closing account and model comment. MINOR: record only, no public correction line.
- [fixed] X11 (WRONG, mills-lamps-versus-trials): Changed eight lamps to eight trials on four lamps, disclosed the two estimated outputs and the conversion assumptions, and removed the unsupported exclusivity statement. Updated source notes and served copies. Added one dated mills-lamps-versus-trials correction; review narrowed its account of the old exclusivity claim to measured efficacies for open-flame lighting.
- [fixed] X12 (WRONG, mills-lamps-versus-trials): Changed eight lamps to eight trials on four lamps, disclosed the two estimated outputs and the conversion assumptions, and removed the unsupported exclusivity statement. Updated source notes and served copies. Added one dated mills-lamps-versus-trials correction; review narrowed its account of the old exclusivity claim to measured efficacies for open-flame lighting.
- [fixed] X13 (WRONG, constants-all-unstated): Changed the heading, live check summary, dek and verifier wording to recovered or cross-checked constants. Added one dated constants-all-unstated correction for the repeated error.
- [fixed] X14 (MINOR, oldest-market-price): Qualified the Babylonian price as the oldest based on quoted market prices and wages, in the panel explanation, recovery list, closing account and model comment. MINOR: record only, no public correction line.
- [fixed] X15 (MINOR, sesame-oil-retail-description): Replaced the unsupported supermarket description with Hunza cold-pressed sesame oil in the paraphrase; retained the verbatim canvas quotation. MINOR: record only, no public correction line.
- [fixed] X16 (MINOR, sesame-oil-retail-description): Replaced the unsupported supermarket description with Hunza cold-pressed sesame oil in the paraphrase; retained the verbatim canvas quotation. MINOR: record only, no public correction line.
- [fixed] X17 (WRONG, candle-comparison-band): Stated that 0.1009 is below 0.1061 to 0.1191 lm/W, disclosed the cross-source assumptions and omitted uncertainty propagation, and removed the claim about a method Nordhaus avoided. Replaced the relaxed verifier test with the actual lower-bound comparison and checked the distinct 77 W and 128.84 W denominators. Added the dated candle-comparison-band correction.
- [fixed] X18 (WRONG, mills-lamps-versus-trials): Changed eight lamps to eight trials on four lamps, disclosed the two estimated outputs and the conversion assumptions, and removed the unsupported exclusivity statement. Updated source notes and served copies. Added one dated mills-lamps-versus-trials correction; review narrowed its account of the old exclusivity claim to measured efficacies for open-flame lighting.
- [fixed] X19 (WRONG, selected-prices-called-frontier): Relabelled the table, budget, caveat and selected modern lamp as selected technologies; corrected generator comments and documentation and regenerated results. Preserved numerical prices and source quotations. Added one dated selected-prices-called-frontier correction for all four copies.
- [fixed] X20 (WRONG, constants-all-unstated): Changed the heading, live check summary, dek and verifier wording to recovered or cross-checked constants. Added one dated constants-all-unstated correction for the repeated error.
- [fixed] X21 (WRONG, centre-corner-ratio-halved): Restored three root three in the relates note and 3*sqrt(3) in the verifier comment. The existing body formula was correct. Added one dated centre-corner-ratio-halved correction.
- [fixed] X22 (WRONG, centre-corner-ratio-halved): Restored three root three in the relates note and 3*sqrt(3) in the verifier comment. The existing body formula was correct. Added one dated centre-corner-ratio-halved correction.
- [fixed] X23 (MINOR, oldest-market-price): Qualified the Babylonian price as the oldest based on quoted market prices and wages, in the panel explanation, recovery list, closing account and model comment. MINOR: record only, no public correction line.
- [fixed] X24 (MINOR, oldest-market-price): Qualified the Babylonian price as the oldest based on quoted market prices and wages, in the panel explanation, recovery list, closing account and model comment. MINOR: record only, no public correction line.
- [fixed] X25 (WRONG, labour-cost-labelled-purchasing-power): Changed the SVG label to labour cost of light; retained the index data. Added the dated labour-cost-labelled-purchasing-power correction. Review replaced its unqualified reciprocal claim with the supported direction: falling labour cost means an hour buys more light.

The ten Corrected 2026-10-18 lines are in public/strata/the-evening-you-could-afford/index.html and mirrored at the end of src/content/strata/the-evening-you-could-afford.md. Each names the assay line and the finding date. No STALE item was supplied, so no Updated line was added. JSON-LD dateModified is 2026-10-18. The shared placard and plain-language button are outside these 25 decisions and were left for their shared workflow.