Robert Ball (1840-1913), Irish astronomer, mathematician and author. Ball was appointed Astronomer Royal of Ireland in 1874. In addition to his astronomical observations, he had a passion for mathematics. Much of his spare time was dedicated to investigating the mechanics of rigid bodies, culminating in his treatise on the theory of screws. His accessible lecturing and writing style gave him a wide popular appeal, and he authored a successful series of books of popular astronomy. He was knighted in 1886.