The Irish mathematical physicist Sir William Rowan Hamilton (1805-1865) reshaped theoretical optics by basing it on his law of varying action. His analysis of motion anticipated several basic notions of relativity and quantum mechanics.

William Rowan Hamilton was born on Aug. 4, 1805, in Dublin, the fourth child of Archibald Hamilton, a solicitor, and Sarah Hutton Hamilton. His father's family was known for a penchant for the gregarious and the romantic, while several members of his mother's family were distinguished scientists. It was the almost clashing union of the scientific and the romantic that became the most marked characteristic of William's personality. At the age of 2 he was entrusted to his uncle, a curate and an accomplished linguist. At the age of 3 William read English fluently; at 5 he was translating Greek and Hebrew; by the time he was 12, he not only had mastered German, French, Italian, and Spanish but also...