Euler E237: Research on the declination of the magnetized needle | English translation | OMH v1.0

English translation of “Recherches sur la déclinaison de l'aiguille aimantée” by Leonhard Euler (Eneström E237), titled “Research on the declination of the magnetized needle.” Prepared for Open Math Heritage with OpenAI-assisted translation, mathematical transcription and LaTeX typesetting. OMH v1.0 is a machine-assisted draft that has undergone a full, fresh AI-assisted technical audit of source coverage, translation, formulas, tables and figures where present, and rendered output. This is not a claim of human scholarly review or certification of the historical mathematics. Version 2 is reserved for a fully reviewed edition. Original publication: Mémoires de l’Académie des sciences de Berlin, vol. 13 (year 1757, printed 1759), pp. 175–251, map and fifteen numbered figures. Shared Plate III also contains figures from the following work, identified separately. Sources: https://scholarlycommons.pacific.edu/euler-works/237/; https://bibliothek.bbaw.de/digitalisierte-sammlungen/akademieschriften. Reproduced BBAW scan assets retain the collection’s stated current CC BY-SA conditions and attribution; no unsupported numbered license version or blanket license for the mixed-content edition is asserted. The original historical text is public domain by age; no publication license is assigned here to the new translation or editorial notes.