EULER, LEONHARD.

Variae Demonstrationes Geometriae. (Various geometric demonstrations).

(Petropoli (St. Petersbourg), 1750). 4to. Uncut, without wrappers. Extracted from "Novi Commentarii Academiae Scientiarum Imperialis Petropolitanae", Tom. I. ad Annum 1747 et 1748. Pp. 49-66 a. 1 engraved plate. Clean and fine.

First printing of an importent paper in geometry in which "Euler says that a proof of a theorem by Fermat can be done from a strictly Euclidean way. He also presents relations about triangles and quadrilaterals, relating products of side lengths, squares of side lengths, and areas." - Enestroem No. 135.

Order-nr.: 42897