Sir William Rowan Hamilton MRIA (4 August 1805 – 2 September 1865) was an Irish mathematician, Andrews Professor of Astronomy at Trinity College Dublin, and Royal Astronomer of Ireland. He worked in both pure mathematics and mathematics for physics. He made important contributions to optics, classical mechanics and algebra. Although Hamilton was not a physicist–he regarded himself as a pure mathematician–his work was of major importance to physics, particularly his reformulation of Newtonian mechanics, now called Hamiltonian mechanics. In pure mathematics, he is best known as the inventor of quaternions.
Hamilton was part of a small but well-regarded school of mathematicians associated with Trinity College in Dublin, which he entered at age 18. The college awarded him two Optimes, or off-the-chart grades. He studied both classics and mathematics (BA in 1827, MA in 1837). While still an undergraduate he was appointed Andrews professor of Astronomy and Royal Astronomer of Ireland. He then took up residence at Dunsink Observatory where he spent the rest of his life.
He was a regular correspondent with both Richard Lovell and Maria Edgeworth. In January 1838, a few days after her seventieth birthday, the celebrated writer, Maria Edgeworth, received a letter from Ireland’s pre-eminent scientist, Sir William Rowan Hamilton, then thirty-two. Hamilton, recently elected President of the Royal Irish Academy, was not sending birthday greetings; rather, he was looking to Miss Edgeworth for advice on an Academy matter – improving the position of literature in the Academy where it languished in comparison to other fields of study. Edgeworth’s advice would inform his inaugural address to the Academy later that month. Her advice was that medals should be awarded to the winners of prize essay competitions, and members’ subscriptions for Academy events should be at affordable levels to permit attendance by the men of literature who were not usually well off. in 1858 he composed a poem in honour of Maria (or Mary as he referred to her).