Alfred George Greenhill

George Greenhill was educated at Christ's Hospital School and from there he went to St John's College, Cambridge in 1866.

[1] In 1876, Greenhill was appointed professor of mathematics at the Royal Military Academy (RMA) at Woolwich, London, UK.

He was one of the world's leading experts on applications of elliptic integrals in electromagnetic theory.

In 1879 Greenhill calculated complicated twist rate formulas for rifled artillery by approximating the projectile as an elongated ellipsoid of rotation in incompressible fluid (which, as he couldn't have known back then, assumes subsonic flight).

[9] This shortcut uses the bullet's length, needing no allowances for weight or nose shape.

Cast bullets as cast (left), with gas check (center) and lubricated (right).