seamus dubhghaill

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


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Death of Mathematician Sir William Rowan Hamilton

Sir William Rowan Hamilton, Irish mathematician, Andrews Professor of Astronomy at Trinity College, Dublin, and Royal Astronomer of Ireland, who makes important contributions to classical mechanics, optics, and algebra, dies in Dublin on September 2, 1865, following a severe attack of gout.

Hamilton is born in Dublin on August 4, 1805, 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 in Dublin 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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Death of Lawrence Parsons, 4th Earl of Rosse

Lawrence Parsons, 4th Earl of Rosse, KP, FRS, a member of the Irish peerage and an amateur astronomer, dies on August 29, 1908. His name is often given as Laurence Parsons.

Parsons is born at Birr Castle, Parsonstown, King’s County (now County Offaly), the son and heir of the astronomer William Parsons, 3rd Earl of Rosse, who built the “Leviathan of Parsonstownreflecting telescope, largest of its day, and his wife, the Countess of Rosse (née Mary Field), an amateur astronomer and pioneering photographer. He succeeds his father in 1867 and is educated first at home by tutors, like John Purser, and after at Trinity College, Dublin and the University of Oxford. He is the brother of Charles Algernon Parsons, inventor of the steam turbine.

Parsons serves as the eighteenth Chancellor of Trinity College, Dublin between 1885 and 1908. His father serves as the sixteenth Chancellor. He is Lord Lieutenant of King’s County and Custos Rotulorum of King’s County from 1892 until his death. He is also a Justice of the Peace for the county and is appointed High Sheriff of King’s County for 1867–68. He is knighted KP in 1890.

Parsons also performs some preliminary work in association with the practices of the electrodeposition of copper sulfate upon silver films circa 1865 while in search of the design for a truly flat mirror to use in a telescope. However, he finds it impossible to properly electroplate copper upon these silver films, as the copper contracts and detaches from the underlying glass substrate. His note has been cited as one of the earliest confirmations in literature that thin films on glass substrates experience residual stresses. He revives discussion in his work Nature’s August 1908 edition after witnessing similar techniques used to present newly-devised searchlights before the Royal Society.

Although overshadowed by his father (when astronomers speak of “Lord Rosse”, it is almost always the father that they refer to), Parsons nonetheless pursues some astronomical observations of his own, particularly of the Moon. Most notably, he discovers NGC 2, a spiral galaxy in the constellation Pegasus.

Parsons is elected a Fellow of the Royal Society in December 1867 and delivers the Bakerian lecture there in 1873. He is vice-president of the society in 1881 and 1887. From 1896 he is President of the Royal Irish Academy. In May 1902 he is at Caernarfon to receive the honorary degree LL.D. (Legum Doctor) from the University of Wales during the ceremony to install the Prince of Wales (later King George V) as Chancellor of that university.


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Birth of George Francis FitzGerald, Academic & Physicist

Professor George Francis FitzGerald FRS FRSE, Irish academic and physicist, is born at No. 19, Lower Mount Street in Dublin on August 3, 1851. He is known for his work in electromagnetic theory and for the Lorentz–FitzGerald contraction, which becomes an integral part of Albert Einstein‘s special theory of relativity.

FitzGerald is born to the Reverend William FitzGerald and his wife Anne Frances Stoney. He is the nephew of George Johnstone Stoney, the Irish physicist who coins the term “electron.” After the particles are discovered by J. J. Thomson and Walter Kaufmann in 1896, FitzGerald is the one to propose calling them electrons. He is also the nephew of Bindon Blood Stoney, an eminent Irish engineer. His cousin is Edith Anne Stoney, a pioneer female medical physicist.

Professor of Moral Philosophy at Trinity College Dublin and vicar of St. Anne’s, Dawson Street, at the time of his son’s birth, William FitzGerald is consecrated Bishop of Cork, Cloyne and Ross in 1857 and translates to Killaloe and Clonfert in 1862. George returns to Dublin and enters TCD as a student at the age of sixteen, winning a scholarship in 1870 and graduating in 1871 in Mathematics and Experimental Science. He becomes a Fellow of Trinity in 1877 and spends the rest of his career there, serving as Erasmus Smith’s Professor of Natural and Experimental Philosophy from 1881 to 1901.

Along with Oliver Lodge, Oliver Heaviside and Heinrich Hertz, FitzGerald is a leading figure among the group of “Maxwellians” who revise, extend, clarify, and confirm James Clerk Maxwell‘s mathematical theories of the electromagnetic field during the late 1870s and the 1880s.

In 1883, following from Maxwell’s equations, FitzGerald is the first to suggest a device for producing rapidly oscillating electric currents to generate electromagnetic waves, a phenomenon which is first shown to exist experimentally by the German physicist Heinrich Hertz in 1888.

In 1883, FitzGerald is elected Fellow of the Royal Society. In 1899, he is awarded a Royal Medal for his investigations in theoretical physics. In 1900, he is made an honorary fellow of the Royal Society of Edinburgh.

FitzGerald is better known for his conjecture in his short letter to the editor of Science. “The Ether and the Earth’s Atmosphere” explains that if all moving objects were foreshortened in the direction of their motion, it would account for the curious null-results of the Michelson–Morley experiment. He bases this idea in part on the way electromagnetic forces are known to be affected by motion. In particular, he uses some equations that had been derived a short time before by his friend the electrical engineer Oliver Heaviside. The Dutch physicist Hendrik Lorentz hits on a very similar idea in 1892 and develops it more fully into Lorentz transformations, in connection with his theory of electrons.

The Lorentz–FitzGerald contraction hypothesis becomes an essential part of the Special Theory of Relativity, as Albert Einstein publishes it in 1905. He demonstrates the kinematic nature of this effect, by deriving it from the principle of relativity and the constancy of the speed of light.

FitzGerald suffers from many digestive problems for much of his shortened life. He becomes very ill with stomach problems. He dies on February 22, 1901 at his home, 7 Ely Place in Dublin, the day after an operation on a perforated ulcer. He is buried in Mount Jerome Cemetery.

A crater on the far side of the Moon is named after FitzGerald, as is a building at Trinity College Dublin.


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Birth of Astronomer William Edward Wilson

William Edward Wilson, Irish astronomer, is born at Greenisland, County Antrim, on July 19, 1851. He is the only son of John and Frances Wilson of Daramona House, Streete, County Westmeath, and is privately educated.

Wilson becomes interested in astronomy and travels to Oran in 1870 to photograph the solar eclipse. In 1871 he acquires a reflecting telescope of 12 inches (30.5 cm) aperture and sets it up in a dome in the gardens of Daramona House. He uses it to experiment on the photography of the moon with wet plates and also begins to study solar radiation using thermopiles. In 1881, he replaces the original telescope with a Grubb reflector of 24 inches (61 cm) aperture and a new dome and mounting that has an electrically controlled clock drive. The new telescope is mounted in a two-story tower attached to the house with an attached physical laboratory, darkroom and machine shop.

Wilson’s main research effort, in partnership with P.L. Gray, is to determine the temperature of the sun using a “differential radio-micrometer” of the sort developed by C.V. Boys in 1889, which combines a bolometer and galvanometer into one instrument. The result of their measurements is an effective temperature of about 8000 °C for the sun which, after correction to deal with absorption in the earth’s atmosphere, give a value of 6590 °C, compared to the modern value of 6075 °C.

Some of Wilson’s other astronomical projects include observations on the transit of Venus, determination of stellar motion, observations of sunspots and a trip to Spain to photograph a solar eclipse. He takes a great many excellent photographs of celestial bodies such as nebulae. His astronomical findings are published in a series of memoirs such as Experimental Observations on the Effective Temperature of the Sun.

Wilson is elected a fellow of the Royal Astronomical Society in 1875 and a Fellow of the Royal Society in 1896. He receives an honorary doctorate (D.Sc.) from the University of Dublin in June 1901. He serves as High Sheriff of Westmeath for 1894.

Wilson dies on March 6, 1908 at Daramona at the relatively young age of 56, and is buried in the family plot in Steete churchyard. He had married Caroline Ada in 1886, the daughter of Capt. R.C. Granville, and they have a son and two daughters. His son donates his telescope to the University of London, where it is used for research and teaching, finally becoming a feature in Liverpool museum.


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Birth of Sir Joseph Larmor, Physicist & Mathematician

Sir Joseph Larmor FRS FRSE, Irish and British physicist and mathematician who makes breakthroughs in the understanding of electricity, dynamics, thermodynamics, and the electron theory of matter, is born in Magheragall, County Antrim on July 11, 1857. His most influential work is Aether and Matter, a theoretical physics book published in 1900.

Larmor is the son of Hugh Larmor, a Belfast shopkeeper and his wife, Anna Wright. The family moves to Belfast around 1860, and he is educated at the Royal Belfast Academical Institution, and then studies mathematics and experimental science at Queen’s College, Belfast, where one of his teachers is John Purser. He obtains his BA in 1874 and MA in 1875. He subsequently studies at St. John’s College, Cambridge where in 1880 he is Senior Wrangler and Smith’s Prizeman, and obtains his MA in 1883. After teaching physics for a few years at Queen’s College, Galway, he accepts a lectureship in mathematics at Cambridge in 1885. In 1892 he is elected a Fellow of the Royal Society of London, and he serves as one of the Secretaries of the society. He is made an Honorary Fellow of the Royal Society of Edinburgh in 1910.

In 1903 Larmor is appointed Lucasian Professor of Mathematics at Cambridge, a post he retains until his retirement in 1932. He never marries. He is knighted by King Edward VII in 1909.

Motivated by his strong opposition to Home Rule for Ireland, in February 1911 Larmor runs for and is elected as Member of Parliament for Cambridge University (UK Parliament constituency) with the Conservative Party. He remains in parliament until the 1922 general election, at which point the Irish question has been settled. Upon his retirement from Cambridge in 1932 he moves back to County Down in Northern Ireland.

Larmor receives the honorary Doctor of Laws (LLD) from the University of Glasgow in June 1901. He is awarded the Poncelet Prize for 1918 by the French Academy of Sciences. He is a Plenary Speaker in 1920 at the International Congress of Mathematicians (ICM) at Strasbourg and an Invited Speaker at the ICM in 1924 in Toronto and at the ICM in 1928 in Bologna.

Larmor dies in Holywood, County Down, Northern Ireland on May 19, 1942.


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Birth of Astronomer William Parsons, 3rd Earl of Rosse

William Parsons, 3rd Earl of Rosse, Anglo-Irish astronomer, naturalist, and engineer, is born in York, England on June 17, 1800. He is President of the Royal Society (UK), the most important association of naturalists in the world in the nineteenth century. He builds several giant telescopes. His 72-inch telescope, built in 1845 and colloquially known as the “Leviathan of Parsonstown,” is the world’s largest telescope, in terms of aperture size, until the early 20th century. From April 1807 until February 1841, he is styled as Baron Oxmantown.

Parsons is the son of Lawrence Parsons, 2nd Earl of Rosse, and Alice Lloyd. He is educated at Trinity College, Dublin and Magdalen College, Oxford, graduating with first-class honours in mathematics in 1822. He inherits an earldom and a large estate in King’s County (now County Offaly) in Ireland when his father dies in February 1841.

Parsons marries Mary Field, daughter of John Wilmer Field, on April 14, 1836. They have thirteen children, of which four sons survive to adulthood: Lawrence, 4th Earl of Rosse, Rev. Randal Parsons, the Hon. Richard Clere Parsons, and the Hon. Sir Charles Algernon Parsons.

In addition to his astronomical interests, Parsons serves as a Member of Parliament (MP) for King’s County from 1821 to 1834, president of the British Science Association in 1843–1844, an Irish representative peer after 1845, president of the Royal Society (1848–1854), and chancellor of Trinity College, Dublin (1862–1867).

During the 1840s, Parsons has the Leviathan of Parsonstown built, a 72-inch telescope at Birr Castle, Parsonstown, County Offaly. He has to invent many of the techniques he uses for constructing the Leviathan, both because its size is without precedent and because earlier telescope builders had guarded their secrets or had not published their methods. Details of the metal, casting, grinding and polishing of the 3-ton ‘speculum’ are presented in 1844 at the Belfast Natural History Society. His telescope is considered a marvelous technical and architectural achievement, and images of it are circulated widely within the British commonwealth. Building of the Leviathan begins in 1842 and it is first used in 1845, with regular use waiting another two years due to the Great Famine. Using this telescope he sees and catalogues a large number of nebulae, including a number that would later be recognised as galaxies.

Parsons performs astronomical studies and discovers the spiral nature of some nebulas, today known to be spiral galaxies. His telescope Leviathan is the first to reveal the spiral structure of M51, a galaxy nicknamed later as the “Whirlpool Galaxy,” and his drawings of it closely resemble modern photographs.

Parsons dies at the age of 67 on October 31, 1867 at Monkstown, County Dublin.

Parsons’s son publishes his father’s findings, including the discovery of 226 New General Catalogue of Nebulae and Clusters of Stars (NGC) objects in the publication Observations of Nebulae and Clusters of Stars Made With the Six-foot and Three-foot Reflectors at Birr Castle From the Year 1848 up to the Year 1878, Scientific Transactions of the Royal Dublin Society Vol. II, 1878.


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Birth of Richard Lovell Edgeworth, Politician, Writer & Inventor

Richard Lovell Edgeworth, Anglo-Irish politician, writer and inventor, is born on May 31, 1744 in Pierrepont Street, Bath, Somerset, England.

Edgeworth is the son of Richard Edgeworth senior, and great-grandson of Sir Salathiel Lovell through his mother, Jane Lovell, granddaughter of Sir Salathiel. The Edgeworth family comes to Ireland in the 1580s. He is descended from Francis Edgeworth, appointed joint Clerk of the Crown and Hanaper in 1606, who inherits a fortune from his brother Edward Edgeworth, Bishop of Down and Connor.

A Trinity College, Dublin and Corpus Christi College, Oxford alumnus, Edgeworth is credited for creating, among other inventions, a machine to measure the size of a plot of land. He also makes strides in developing educational methods. He anticipates the caterpillar track with an invention that he plays around with for forty years but never successfully develops. He describes it as a “cart that carries its own road.”

Edgeworth is married four times, including both Honora Sneyd and Frances Beaufort, older sister of Francis Beaufort of the Royal Navy. He is the father of 22 children by his four wives. Beaufort and he install a semaphore line for Ireland. He is a member of the Lunar Society of Birmingham. The Lunar Society evolves through various degrees of organization over a period of years, but is only ever an informal group. No constitution, minutes, publications or membership lists survive from any period, and evidence of its existence and activities is found only in the correspondence and notes of those associated with it. Dates given for the society range from sometime before 1760 to it still operating as late as 1813. Fourteen individuals have been identified as having verifiably attended Lunar Society meetings regularly over a long period during its most productive time: these are Matthew Boulton, Erasmus Darwin, Thomas Day, Richard Lovell Edgeworth, Samuel Galton, Jr., James Keir, Joseph Priestley, William Small, Jonathan Stokes, James Watt, Josiah Wedgwood, John Whitehurst and William Withering.

Edgeworth and his family live in Ireland at his estate at Edgeworthstown, County Longford, where he reclaims bogs and improves roads. He sits in Grattan’s Parliament for St. Johnstown (County Longford) from 1798 until the Act of Union 1801, and advocates Catholic Emancipation and parliamentary reform. He is a founder-member of the Royal Irish Academy.

Edgeworth dies in Edgeworthstown on June 13, 1817.

(Pictured: “Portrait of Richard Lovell Edgeworth (1744-1817)” oil on canvas by Hugh Douglas Hamilton)


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Birth of Thomas Romney Robinson, Astronomer & Physicist

Reverend John Thomas Romney Robinson, 19th-century astronomer and physicist usually referred to as Thomas Romney Robinson, was born at St. Anne’s in Dublin on April 23, 1792. He is the longtime director of the Armagh Observatory, one of the chief astronomical observatories in the United Kingdom at the time. He is remembered as the inventor in 1846 of the Robinson 4-cup anemometer, a device for measuring the speed of the wind.

Robinson is the son of the English portrait painter Thomas Robinson (d.1810) and his wife, Ruth Buck (d.1826). He is educated at Belfast Academy then studies Divinity at Trinity College Dublin, where he is elected a Scholar in 1808, graduating BA in 1810 and obtaining a fellowship in 1814, at the age of 22. He is for some years a deputy professor of natural philosophy (physics) at Trinity.

In 1823, at the age of 30, Robinson gains the appointment of astronomer at the Armagh Observatory. From this point on he always resides at the Armagh Observatory, engaged in researches connected with astronomy and physics, until his death in 1882. Having also been ordained as an Anglican priest while at Trinity, he obtains the church livings of the Anglican Church at Enniskillen and at Carrickmacross in 1824.

During the 1840s and 1850s Robinson is a frequent visitor to the world’s most powerful telescope of that era, the so-called Leviathan of Parsonstown telescope, which had been built by Robinson’s friend and colleague William Parsons, 3rd Earl of Rosse. He is active with Parsons in interpreting the higher-resolution views of the night sky produced by Parsons’ telescope, particularly with regard to the galaxies and nebulae and he publishes leading-edge research reports on the question.

Back at his own observatory in Armagh, Robinson compiles a large catalogue of stars and writes many related reports. In 1862 he is awarded a Royal Medal “for the Armagh catalogue of 5345 stars, deduced from observations made at the Armagh Observatory, from the years 1820 up to 1854; for his papers on the construction of astronomical instruments in the memoirs of the Astronomical Society, and his paper on electromagnets in the Transactions of the Royal Irish Academy.”

Robinson is president of the Royal Irish Academy from 1851 to 1856, and is a long-time active organiser in the British Association for the Advancement of Science. He is a friend of Charles Babbage, who says was “indebted” for having reminded him about the first time he came up with the idea of the calculating machine.

Robinson marries twice, first to Eliza Isabelle Rambaut (d.1839) and secondly to Lucy Jane Edgeworth (1806–1897), the lifelong disabled daughter of Richard Lovell Edgeworth. His daughter marries the physicist George Gabriel Stokes. Stokes frequently visits Robinson in Armagh in Robinson’s later years.

Robinson dies in Armagh, County Armagh at the age of 89 on February 28, 1882.

The crater Robinson on the Moon is named in his honour.


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Birth of Robert Boyle, Philosopher, Writer & Chemist

Robert Boyle, Anglo-Irish natural philosopher, theological writer, chemist, physicist, inventor and a preeminent figure of 17th-century intellectual culture, is born on January 25, 1627 at Lismore Castle, in County Waterford.

At age eight, Boyle begins his formal education at Eton College, where his studious nature quickly becomes apparent. In 1639 he and his brother Francis embark on a grand tour of the continent together with their tutor Isaac Marcombes. In 1642, owing to the Irish rebellion, Francis returns home while Robert remains with his tutor in Geneva and pursues further studies.

Boyle returns to England in 1644, where he takes up residence at his hereditary estate of Stalbridge in Dorset. There he begins a literary career writing ethical and devotional tracts, some of which employ stylistic and rhetorical models drawn from French popular literature, especially romance writings. In 1649 he begins investigating nature via scientific experimentation. From 1647 until the mid-1650s, he remains in close contact with a group of natural philosophers and social reformers gathered around the intelligencer Samuel Hartlib. This group, the Hartlib Circle, includes several chemists who heighten his interest in experimental chemistry.

Boyle spends much of 1652–1654 in Ireland overseeing his hereditary lands and performing some anatomic dissections. In 1654 he is invited to Oxford, and he takes up residence at the university until 1668. In Oxford he is exposed to the latest developments in natural philosophy and becomes associated with a group of notable natural philosophers and physicians, including John Wilkins, Christopher Wren, and John Locke. These individuals, together with a few others, form the “Experimental Philosophy Club.” Much of Boyle’s best known work dates from this period.

In 1659 Boyle and Robert Hooke, the clever inventor and subsequent curator of experiments for the Royal Society, complete the construction of their famous air pump and use it to study pneumatics. Their resultant discoveries regarding air pressure and the vacuum appear in Boyle’s first scientific publication, New Experiments Physico-Mechanicall, Touching the Spring of the Air and Its Effects (1660). Boyle and Hooke discover several physical characteristics of air, including its role in combustion, respiration, and the transmission of sound. One of their findings, published in 1662, later becomes known as “Boyle’s law.” This law expresses the inverse relationship that exists between the pressure and volume of a gas, and it is determined by measuring the volume occupied by a constant quantity of air when compressed by differing weights of mercury.

Among Boyle’s most influential writings are The Sceptical Chymist (1661), which assails the then-current Aristotelian and especially Paracelsian notions about the composition of matter and methods of chemical analysis, and the Origine of Formes and Qualities (1666), which uses chemical phenomena to support the corpuscularian hypothesis. He argues so strongly for the need of applying the principles and methods of chemistry to the study of the natural world and to medicine that he later gains the appellation of the “father of chemistry.”

Boyle is a devout and pious Anglican who keenly champions his faith. He sponsors educational and missionary activities and writes a number of theological treatises. He is deeply concerned about the widespread perception that irreligion and atheism are on the rise, and he strives to demonstrate ways in which science and religion are mutually supportive. For Boyle, studying nature as a product of God’s handiwork is an inherently religious duty. He argues that this method of study would, in return, illuminate God’s omnipresence and goodness, thereby enhancing a scientist’s understanding of the divine. The Christian Virtuoso (1690) summarizes these views and may be seen as a manifesto of his own life as the model of a Christian scientist.

In 1668 Boyle leaves Oxford and takes up residence with his sister Katherine Jones, Vicountess Ranelagh, in her house on Pall Mall in London. There he sets up an active laboratory, employs assistants, receives visitors, and publishes at least one book nearly every year. Living in London also provides him the opportunity to participate actively in the Royal Society.

Boyle is a genial man who achieves both national and international renown during his lifetime. He is offered the presidency of the Royal Society and the episcopacy but declines both. Throughout his adult life, he is sickly, suffering from weak eyes and hands, recurring illnesses, and one or more strokes. He dies in London at age 64 on December 31, 1691 after a short illness exacerbated by his grief over Katherine’s death a week earlier. He leaves his papers to the Royal Society and a bequest for establishing a series of lectures in defense of Christianity. These lectures, now known as the Boyle Lectures, continue to this day.


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Birth of Physicist Daniel Joseph Bradley

Daniel Joseph Bradley, physicist and Emeritus Professor of Optical Electronics at Trinity College, Dublin, is born on January 18, 1928 in Derry, County Londonderry, Northern Ireland.

Bradley is one of four surviving children of John and Margaret Bradley, Lecky Road, Derry. He leaves school to work as a telegraph boy but returns to education at St. Columb’s College. Following training as a teacher at St. Mary’s Training College, Belfast, he qualifies in 1947. While teaching in a primary school in Derry he studies for a degree in mathematics as an external student of the University of London, and is awarded a degree in 1953.

Moving to London where he teaches mathematics in a grammar school, Bradley decides to register for an evening course at Birkbeck College. His first choice is mathematics but as he already has a degree in the subject the admissions staff suggests that he study physics. In 1957, after four years of part-time study, he is awarded a Bachelor of Science degree in physics by Birkbeck, achieving the highest marks in his final exams in the University of London overall. He next joins Royal Holloway College as an assistant lecturer and simultaneously enrolls as a PhD student, working on Fabry–Pérot interferometer etalon-based high-resolution spectroscopy supervised by Samuel Tolansky. He receives a PhD in 1961.

Bradley is a pioneer of laser physics, and his work on the development of ultra-fast pulsed lasers adds a new and vitally important element to the capabilities of this new type of light source. In particular, working on dye lasers, he produces pulses of light as short as one picosecond (one picosecond is to a second as a second is to 31,800 years). His work paves the way for the completely new field of non-linear optical interactions. In addition, he inspires a new generation of laser scientists in Ireland and the UK, many of whom are international leaders in their fields.

Appointed to a lectureship in the physics department at Imperial College London, Bradley sets up a research programme in UV solar spectroscopy using rocket technology to reach high altitudes.

In 1963 Bradley begins work in laser physics but returns to Royal Holloway College as a reader one year later. In 1966 he is appointed professor and head of department at Queen’s University, Belfast. There he quickly establishes a space research group of international standing to do high-resolution solar spectroscopy. He attracts significant funding from a variety of agencies, allowing him to build his department into one of the world’s leading laser research centres, involving a total of 65 scientists. However, he leaves Belfast because of fears for his family’s safety as political violence escalates in the early 1970s amidst The Troubles.

Bradley returns to Imperial College London in 1973 to a chair in laser physics and heads a group in optical physics, laser physics and space optics. He is head of the Physics department from 1976 to 1980 but is frustrated by cutbacks and a rule governing the ratio of senior to junior positions, one consequence of which is that he is unable to maintain a long-established chair in optical design. He is also critical of the college administration’s handling of some departmental grant applications. He resigns in 1980 and moves to Dublin.

Among Bradley’s many lasting contributions to laser research in the UK is the setting up of one of the world’s leading research facilities for laser research, the Central Laser Facility at the Rutherford Appleton Laboratory (RAL).

Arriving at Trinity College, Dublin, Bradley decides the time is ripe to move on from laser research and development into laser applications. In 1982, with Dr. John Kelly, a chemist, and Dr. David McConnell, a geneticist, he forms a team which wins funding for a project using laser techniques to explore the structure of organic molecules like DNA and proteins. Unfortunately, however, his work at Trinity is cut short by ill health and he retires in 1984. His research on semiconductor lasers is carried on and this work on developing widely tuneable lasers for optical communications systems continues.

A member of the Royal Irish Academy, Bradley is Fellow Emeritus of Trinity College Dublin, and holds fellowships of the Royal Society, The Optical Society of America and Institute of Physics. Through time the ravages of his illness restricts his travelling and eventually he is cared for in a residential home in Dublin, where he passes away on February 7, 2010.