An Instrument of Mass Calculation made by Nastūlus in Baghdad ca. 900
Bibliographic record
Abstract
This remarkable astronomical instrument was made by the Muslim astronomer known as NasÐūlus, who was active in Baghdad between 890 and 930. Its rediscovery brings our knowledge of the activities in that flourishing scientific centre a substantial step further. This type of instrument was previously not known to exist, although sundials based on the same principle are described in Arabic treatises datable to ca. 950 and ca. 1280. It is essentially a mathematical device providing a graphic solution to a problem that was of interest to Muslim astronomers, namely, the determination of the time of day as a function of the solar altitude throughout the year, here specifically for the latitude of Baghdad. The instrument reveals a level of mathematical competence and sophistication that is at first sight astounding. However, with a deeper understanding of the scientific milieu from which it came, it can be seen to be fully within the theoretical competence of the scientists of that environment. Nevertheless, the spectacular accuracy of the engraving of the principal curves on the instrument is completely unexpected. The instrument also features the earliest known solar and calendrical scales from the Islamic East; the origin of these was previously thought to be in the Islamic West.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.020 | 0.005 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".