## Newton Isaac

, Sir **Isaac** 1642–1727.

English mathematician and scientist who developed the techniques of calculus and formulated the theory of universal gravitation, a corpuscular theory of light, and three laws of motion. His theory of gravitation, presented in

*Principia Mathematica*(1687), was supposedly inspired by the sight of a falling apple.*Related Forms:*

**New·to′ni·an**adjective

**Isaac Newton**

1726 portrait by

Enoch Seeman (1694–1744)