https://famulus.lettre.ai/euler/lettre/2026-11-10T00:00:00Z https://famulus.lettre.ai/euler/lettre/1/2026-11-10T00:00:00ZGerd Graßhoff

One segment of a historical source is taken through its argument: the end of §22 and §§24 to 29 of Euler's Inquisitio physica in causam fluxus ac refluxus maris (Eneström 57), seven pages of Opera omnia II 31, in which Euler derives the force by which the sun or the moon tends to raise the tides. The segment is divided into twelve passages. Each passage is quoted in Latin and in English and set beside the step of the reconstruction that says the same thing explicitly, with its premises, the rule that licenses it, and the result of a check. Annotations stand in a third column. The texts are not typed: the Latin is taken from the page of the edition, the English from the edition's stored translation, and every passage links to its page in the edition. The reconstruction confirms Euler's exact components and his expansion. It follows the first edition and the manuscript against an emendation of the editor, which a test shows to be wrong. It marks where it does not follow Euler's route: the resolution by similar triangles in §26 is compared with the result, not rebuilt. The format, called an exposition, is general.