Quaker Benjamin Robins published the treatise New Principles of Gunnery in England, in which he used his meticulous observations, Boyle’s Law, and the centripetal forces drawn from Newton’s Principia, to calculate the velocity and trajectory of a projectile as it exits the muzzle. He also calculated air resistance, which could be up to 120 times the projectile’s weight, radically changing the theoretical Galilean trajectory. He also calculated the effects of rifled barrels, projectile rotation, and gyroscopic effects. He even recommended oval-shaped projectiles and internally rifled barrels.
