Samuel Earnshaw (1 February 1805, Sheffield, Yorkshire – 6 December 1888, Sheffield, Yorkshire[1]) was an English clergyman and mathematician and physicist, noted for his contributions to theoretical physics, especially for proving Earnshaw's theorem.
Earnshaw was born in Sheffield and entered St John's College, Cambridge, graduating Senior Wrangler and Smith's Prizeman in 1831.
For a time he acted as curate to the Revd Charles Simeon.
In 1847 his health broke down and he returned to Sheffield working as a chaplain and teacher.
His most famous contribution, Earnshaw's theorem, shows the impossibility of stability of matter under purely electrostatic forces: other topics included optics, waves, dynamics and acoustics in physics, calculus, trigonometry and partial differential equations in mathematics.