John Constable · Yale Center for British Art · B1981.25.156
Cloud Study
“Sept[ber] 13th one o’clock. | Slight wind at North West, | which became tempestuous | in the afternoon, with | Rain all the night following.”
Museum transcription. Source record. Each underlined phrase links to its claim.
The inscription gives 13 September without a year. Yale’s catalogue supplies 1821. One o’clock is treated as afternoon for the solar comparison; the clock basis is not established.
Finding · Nephos analysis · version 2026-09-09
Both Constable and Howard give NW, and Howard reports a rainy night. These partly agree with the inscription. The sources do not establish the change from slight to tempestuous wind, or rain lasting the whole night.
The Nephos method
How this study was read
The method in fullWhat is written
13 September 1821, one o’clock.
Sept[ber] 13th one o’clock. Slight wind at North West, which became tempestuous in the afternoon, with Rain all the night following.
Yale Center for British Art, B1981.25.156, as the museum transcribes it
Records of those days
- Luke Howard’s registerPrinted daily wind, thermometer and notes, The Climate of London. Kept at Tottenham or Stratford, not Hampstead.
- 20th Century ReanalysisA modern reconstruction for a 1° cell about 111 by 68 km, estimated from pressure, not observed.
Each claim tested
- “Sept[ber] 13th” The inscription gives 13 September without a year.
- “one o’clock.” The computed Sun describes the light available at an assumed place and hour.
- “Slight wind at North West,” Both give NW.
- “which became tempestuous | in the afternoon,” The daily wind entry does not establish an afternoon change in strength.
- “Rain all the night following.” Howard writes “rainy night.” That partly agrees with night rain, but does not establish continuous rain through the whole night at the painter’s position.
Verdict
Both Constable and Howard give NW, and Howard reports a rainy night.
- Partially agrees“Slight wind at North West,”, “Rain all the night following.”
- Unknown“Sept[ber] 13th”, “one o’clock.”, “which became tempestuous | in the afternoon,”
01 · The evidence
The claims and their witnesses.
Each phrase of the inscription is a claim. Each column is a witness that never saw the painting, with its own place, scale and limit.
How to read itRead across one row: the phrase Constable wrote, what each witness can say about it, and the verdict on the right. A dash means that witness has nothing to offer on that claim.
| Claim | Howard registerPrinted table · Source | Weather reconstruction20th Century Reanalysis · Source | The sunComputed · Hampstead assumed · Source | Verdict and limit |
|---|---|---|---|---|
| “Sept[ber] 13th” Unknown |
The register has an entry for this day. Nothing in it names a painter. Page image | — | — | The inscription gives 13 September without a year. Yale’s catalogue supplies 1821. One o’clock is treated as afternoon for the solar comparison; the clock basis is not established. No independent source assembled here dates the painting. Link to claim |
| “one o’clock.” Unknown |
— | — | 40.4° altitude · 201.4° azimuthAt 13:00 local mean time; Hampstead assumed. Computation. | The computed Sun describes the light available at an assumed place and hour. No independently identified landmark or measured painted solar direction establishes the time of execution. Link to claim |
| “Slight wind at North West,” Partially agrees |
NWPage image | Wind from 317° · 2.0 m/s; 59 ± 37% cloud; 15.9 ± 2.4°C12:00 UTC; a regional cell, about 111 × 68 km. Mean and one-sigma spread. Query sources. | — | Both give NW. Howard’s daily direction is from another place and gives no strength, so “Slight” is not independently established. Link to claim |
| “which became tempestuous | in the afternoon,” Unknown |
NWPage image | — | — | The daily wind entry does not establish an afternoon change in strength. The regional reconstruction is not an observation at Constable’s position. Link to claim |
| “Rain all the night following.” Partially agrees |
“Cloudy: rainy night.” Note page image. | — | — | Howard writes “rainy night.” That partly agrees with night rain, but does not establish continuous rain through the whole night at the painter’s position. Link to claim |
Described. Words used by a person in a particular context: the inscription and the printed register. A felt quality cannot be converted into a threshold, and strength words have no shared numerical scale.
Modelled. A reconstruction describes a regional cell. It is not an observation at the easel. No weather agreement independently establishes a painting's date.
02 · The witnesses
What each source can reach.
Howard · 13 September 1821
The printed register
NW · 66° / 51°F
Wind and first thermometer, maximum/minimum for 13 September 1821. Page image.
“Cloudy: rainy night.” Note page image.
The table does not establish conditions at Constable’s position. Supplementary Tottenham observations are kept separate from the main register.
The computed sun
40.4° altitude · 201.4° azimuth
At 13:00 local mean time; 51.560° N, 0.165° W is an assumed Hampstead position. No cited source establishes the clock basis; local mean time there trails UTC by about 40 seconds.
A solar calculation supplies no observation of the painting's execution. No painted angular measurement is established here.
Weather reconstruction
Regional context
Wind from 317° · 2.0 m/s; 59 ± 37% cloud; 15.9 ± 2.4°C
12:00 UTC at 52° N, 0° E. Wind speed and bearing calculated from the mean u/v components; component spreads are retained in the query sources. Cloud and temperature show mean and one-sigma spread. This is a 1° cell about 111 × 68 km. No local wind-strength scale or capture cloud measurement is established here.
03 · Making the artwork
The sky passed through an artist's decisions.
Production uncertainty is separate from weather uncertainty. The located sources do not establish every stage of this object's making, and “unknown” is not evidence that a stage did not happen.
- Locationpartly known
- No place is transcribed in this museum entry. The exact easel coordinates are not established; the solar comparison uses the assumed Hampstead position.
- Date evidence
- The inscription gives 13 September without a year. Yale’s catalogue supplies 1821. One o’clock is treated as afternoon for the solar comparison; the clock basis is not established. Museum source.
- Outdoor executionunresolved
- The evidence assembled here does not establish that every passage was executed outdoors in the stated interval.
- Preparatory work and later changesunknown
- No complete sequence or timing of working sessions is established by the sources assembled here. No technical examination of this object is offered.
04 · Revisions
How the reading changed.
- Sources assembled
- The museum transcription is placed beside the independently dated register and modelled context. Catalogue qualifications remain explicit.
- What remains open
- This is the first Nephos record for this object. No earlier verdict is being revised.
05 · Take this into your work
A record you can cite, print or embed.
Cite individual claims by their link, and cite museum and historical sources directly when using their statements. Nephos analysis is independent of the holding institution; image licences are separate from the research text.
Machine-readable
For the Yale Center for British Art: this record is for B1981.25.156. If it is right, link it from your object page; if anything is wrong, write to Nephos and it will be corrected the same day.
The museum’s catalogue remains the authority. Nephos does not claim endorsement.
06 · Sources
Follow every claim.
- M1Yale Center for British Art: John Constable, Cloud Study, B1981.25.156. Object page; museum transcription. The catalogue date gives the year and the museum transcription supplies the day and month.
- H1Luke Howard, The Climate of London, 2nd edition, vol. III (London: Harvey and Darton, 1833); Table CLXXXIV, p. 60; continuation and results, p. 61 Page image. Printed monthly results.
- S1Skyfield 1.55 with JPL DE440. Apparent topocentric Sun without atmospheric refraction. The place and clock basis are assumptions; the calculation is recorded in the JSON-LD record.
- R1NOAA-CIRES-DOE 20th Century Reanalysis v3. tcdc mean · tcdc spread · uwnd mean · uwnd spread · vwnd mean · vwnd spread · air mean · air spread
