Emery ball

An emery ball is an illegal pitch in baseball, in which the ball has been altered by scuffing it with a rough surface, such as an emery board or sandpaper. This technique alters the spin of the ball, causing it to move in an atypical manner, as more spin makes the ball rise, while less spin makes the ball drop. The general term for altering the ball in any way is doctoring.^[1] The emery ball differs from the spitball, in which the ball is doctored by applying saliva or Vaseline. Vaseline or saliva smooths the baseball, while the emery paper roughens it.

Russ Ford discovered the emery ball in the minor leagues in 1907 when he saw what a scuff on a baseball did to its movement. He began keeping emery paper in his baseball glove. Though he initially kept the pitch a secret, he had to inform his catcher, Ed Sweeney, about it. Sweeney taught it to other pitchers, and the pitch was discovered when an umpire found emery paper in Ray Keating's glove in 1914. The pitch was outlawed, and led to the banning of the spitball.