(Berlin, Haude et Spener, 1769). 4to. No wrappers as issued in "Memoires de l'Academie Royale des Sciences et Belles Lettres". tome XVIII, 1762. With halftitle "Classe de Mathematique" (2) pp. + pp. 117-142. Clean and fine.
An original paper ( first printing) by Euler dealing with the mathematics of problems in the manufacturing of lenses.
Enestroem: E 376.
Order-nr.: 48878