Leonhard Euler

Eyesight deterioration Euler's eyesight worsened throughout his mathematical career. In 1738, three years after nearly dying of fever, he became almost blind in his right eye. Euler blamed the cartography he performed for the St. Petersburg Academy for his condition,

Music One of Euler's more unusual interests was the application of mathematical ideas in music. In 1739 he wrote the Tentamen novae theoriae musicae (Attempt at a New Theory of Music), hoping to eventually incorporate music theory as part of mathematics. This part of his work, however, did not receive wide attention and was once described as too mathematical for musicians and too musical for mathematicians. Even when dealing with music, Euler's approach is mainly mathematical, Mathematician François Arago said, "Euler calculated without any apparent effort, just as men breathe and as eagles sustain themselves in air". He is generally ranked right below Carl Friedrich Gauss, Isaac Newton, and Archimedes among the greatest mathematicians of all time,