Euler, Leonhard (1707-1783)

Leonard Euler was an outstanding mathematician. A friend of Daniel Bernoulli, he obtained his masters degree from the University of Basle at the age of 16 and gained his first faculty position (partly due to Bernoulli's influence) at St. Petersburg in 1727. He was a prolific thinker and was well known for his ability to perform complex calculations in his head. He published well over 600 books and papers, mostly in Latin, on topics covering every aspect of pure and applied mathematics, physics and astronomy. His most significant contributions however were in analytic geometry, calculus (developing integral and differential calculus to their modern forms) and trigonometry (developing spherical geometry). His general analysis of the three-dimensional motion of rigid bodies is regarded by many as one of the high points of classical mechanics and was an important milestone in the shift from 'geometric' arguments of the kind used by Newton to the algebraic and analytic methods that were destined to dominate later work. He also introduced much of the mathematical notation still in use today, including for imaginary numbers, for summations, for functions and e for the base of natural logarithms.

Euler lost the sight of one eye while he was observing the Sun and although later totally blind (he lost the other eye through a cataract), he spent the last fifteen years of his life mainly carrying out research into the motions and positions of the Moon, studying the gravitational effects between the Moon, Sun and Earth.