EULER, Leonhard

2 years bound together in 1 vol. in-4to, [viii], 560, [30] pages, ill. with 6 copper plates. The most important article in this scientific volume is: Constructio aequationum quarundam differentialium quae indeterminatarum separationem non admittunt. (on pages 369-373) This translates as: 'The transformation of certain differential equations, which do not permit the separation of variables'; it concerns the Ricatti equation. Age-toned due to the quality of the paper. Contemporary polished calf binding, spine richly gilt, red edges