seamus dubhghaill

Promoting Irish Culture and History from Little Rock, Arkansas, USA

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Birth of Mathematician William Rowan Hamilton

william-rowan-hamiltonSir William Rowan Hamilton, Irish mathematician who makes important contributions to classical mechanics, optics, and algebra, is born in Dublin on August 4, 1805.

Hamilton is the fourth of nine children born to Sarah Hutton (1780–1817) and Archibald Hamilton (1778–1819). He is part of a small but well-regarded school of mathematicians associated with Trinity College, Dublin, which he enters at age eighteen. He is said to have shown immense talent at a very early age. Astronomer Bishop Dr. John Brinkley remarks of the 18-year-old Hamilton, “This young man, I do not say will be, but is, the first mathematician of his age.”

Trinity College awards him two Optimes, or off-the-chart grades. He studies both classics and mathematics, and is appointed Professor of Astronomy just prior to his graduation. He then takes up residence at Dunsink Observatory where he spends the rest of his life.

Although Hamilton regards himself as a pure mathematician rather than a physicist, his work is of major importance to physics, particularly his reformulation of Newtonian mechanics, now called Hamiltonian mechanics. This work has proven central to the modern study of classical field theories such as electromagnetism, and to the development of quantum mechanics. In pure mathematics, he is best known as the inventor of quaternions.

Hamilton’s scientific career includes the study of geometrical optics, classical mechanics, adaptation of dynamic methods in optical systems, applying quaternion and vector methods to problems in mechanics and in geometry, development of theories of conjugate algebraic couple functions, solvability of polynomial equations and general quintic polynomial solvable by radicals, the analysis on Fluctuating Functions, linear operators on quaternions and proving a result for linear operators on the space of quaternions, which is a special case of the general theorem which today is known as the Cayley–Hamilton theorem. He also invents Icosian calculus, which he uses to investigate closed edge paths on a dodecahedron that visit each vertex exactly once.

Hamilton retains his faculties unimpaired to the very last, and steadily continues the task of finishing the Elements of Quaternions which occupies the last six years of his life. He dies on September 2, 1865, following a severe attack of gout precipitated by excessive drinking and overeating. He is buried in Mount Jerome Cemetery in Dublin.


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Birth of William Frederick Archdall Ellison, Clergyman & Astronomer

Reverend William Frederick Archdall Ellison FRAS, Irish clergyman, Hebrew scholar, organist, avid amateur telescope maker, and, from 1918 to 1936, director of Armagh Observatory in Armagh, Northern Ireland, is born on April 28, 1864. He is the father of Mervyn A. Ellison, the senior professor of the School of Cosmic Physics at Dunsink Observatory from 1958 to 1963.

Ellison comes from a clerical family, his father Humphrey Eakins Ellison having been Dean of Ferns, County Wexford. He gains a sizarship of classics at Trinity College, Dublin in 1883, becomes a Scholar of the House in 1886 and graduates in 1887 with junior moderatorships in classics and experimental science. In 1890 he takes Holy Orders and moves to England, where he becomes the Curate of Tudhoe and Monkwearmouth. In 1894 he takes his MA and BD degrees and in the following year wins the Elrington Theological Prize.

In 1899 he returns to Ireland to become secretary of the Sunday School Society, a post which he holds for three years before accepting the incumbency of Monart, Enniscorthy, moving in 1908 to become Rector of Fethard-on-Sea with Tintern in Wexford. Ellison develops an interest in astronomy, having been introduced to practical optics by Dr. N. Alcock of Dublin and sets up his first observatory at Wexford. He becomes highly adept at making lenses and mirrors and writes several books and articles on the subject, including major contributions to the Amateur Telescope Making series, the Journal of the British Astronomical Association, and the weekly newspaper The English Mechanic. His book The Amateur’s Telescope (1920) is still considered a standard for telescope-makers and a forerunner of the more extensive series on the same topic by Albert Graham Ingalls.

On September 2, 1918 Ellison is appointed Director of the Armagh Observatory. He finds the Observatory in a state of disrepair and sets about repairing the instruments and the observatory dome. On January 3, 1919 he deeds a telescope of his own to the observatory, an 18-inch reflecting telescope, which is still there.

Ellison is a highly regarded planetary and binary star observer. Working with his son Mervyn, he makes many measurements of binary stars using the observatory’s 10-inch Grubb refracting telescope and even discovers a new one close to Beta Lyrae, and according to Patrick Moore, is one of the few people to have observed an eclipse of Saturn’s moon Iapetus by Saturn’s outermost ring on February 28, 1919.

In 1934 Ellison becomes Canon and Prebendary of Ballymore, Armagh Cathedral. He dies on December 31, 1936, having held the office of Director of the observatory for nearly twenty years.