Leonhard Euler (1707 – 1783)
Euler was one of greatest mathematicians of the period of Enlightenment. Born in Switzerland but worked most of his life in Russia and Germany. He made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function. He is also renowned for his work in mechanics, fluid dynamics, optics, astronomy, and music theory.
Euler's involvement with cartography began by his tuition by the great French cartographer Delisle who had been invited to work at the Petersburg Academy Observatory. Delisle taught Euler astronomy and observational techniques with telescopes and other instruments. In September 1734 Delisle suggested that Euler work with a three foot quadrant prior to working independently making observations the following month. The results of Euler's research and observation into determining longitude, led later to the formation of the geography department of the academy.