‎"EULER, [LEONHARD].‎
‎Recherches sur les lunettes a trois verres qui representent les objets renverses. - [EULER ON GLASSES WITH THREE LENSES]‎

‎(Berlin, Haude et Spener, 1759). 4to. No wrappers as issued in ""Memoires de l'Academie Royale des Sciences et Belles Lettres"". tome X, pp. 323-372.‎

Reference : 44266

‎First printing of this paper in which Euler made important research into the field of optics and how to construct glasses with three lenses. ""Euler composed his object-glasses of two bi-convex lenses of crown-glas, and a bi-concave of flint, to form a triple object-glass of six lines focal distance with a large aperture"" and it is because our microscope is achromatic that it is established on the principles of Euler."" (Brewster. The Edinburgh journal of science. P. 225).See Eneström E240. ‎