James MacCullagh (1809 – 24 October 1847) was an Irish mathematician.
Early Life
MacCullagh was born in
Landahaussy
Landahaussy or Landahussy (possibly ) is a small village and townland near Plumbridge in County Tyrone, Northern Ireland. It is within the Derry City and Strabane District Council area.Plumbridge
Plumbridge is a small village in County Tyrone, Northern Ireland. It is a crossroads village, standing on the banks of the Glenelly River. In the 2001 Census it had a population of 267 people. It lies within Derry City and Strabane District ar ...
,
County Tyrone
County Tyrone (; ) is one of the six Counties of Northern Ireland, counties of Northern Ireland, one of the nine counties of Ulster and one of the thirty-two traditional Counties of Ireland, counties of Ireland. It is no longer used as an admini ...
, Ireland, but the family moved to Curly Hill,
Strabane
Strabane ( ; ) is a town in County Tyrone, Northern Ireland.
Strabane had a population of 13,172 at the 2011 Census. It lies on the east bank of the River Foyle. It is roughly midway from Omagh, Derry and Letterkenny. The River Foyle marks ...
when James was about 10.
[Dictionary of Irish Biography: MacCullagh, James]
/ref> He was the eldest of twelve children and demonstrated mathematical talent at an early age. He entered Trinity College Dublin
, name_Latin = Collegium Sanctae et Individuae Trinitatis Reginae Elizabethae juxta Dublin
, motto = ''Perpetuis futuris temporibus duraturam'' (Latin)
, motto_lang = la
, motto_English = It will last i ...
as a student in 1824, winning a scholarship in 1827 and graduating in 1829.
Career
He became a fellow of Trinity College Dublin in 1832 and was a contemporary there of William Rowan Hamilton
Sir William Rowan Hamilton Doctor of Law, LL.D, Doctor of Civil Law, DCL, Royal Irish Academy, MRIA, Royal Astronomical Society#Fellow, FRAS (3/4 August 1805 – 2 September 1865) was an Irish mathematician, astronomer, and physicist. He was the ...
. He became a member of the Royal Irish Academy
The Royal Irish Academy (RIA; ga, Acadamh Ríoga na hÉireann), based in Dublin, is an academic body that promotes study in the sciences, humanities and social sciences. It is Ireland's premier List of Irish learned societies, learned socie ...
in 1833. In 1835 he was appointed Erasmus Smith's Professor of Mathematics at Trinity College Dublin and in 1843 became . He was an inspiring teacher and taught notable scholars, including Samuel Haughton
Samuel Haughton (21 December 1821 – 31 October 1897) was an Irish clergyman, medical doctor, and scientific writer.
Biography
The scientist Samuel Haughton was born in Carlow, the son of another Samuel Haughton (1786-1874) and grandson (by h ...
, Andrew Searle Hart
Sir Andrew Searle Hart (1811–1890) was an Anglo-Irish mathematician and Vice-Provost of Trinity College Dublin (TCD).
Early life and background
He was the youngest son of the Rev. George Vaughan Hart of Glenalla, County Donegal, and his wife ...
, John Kells Ingram
John Kells Ingram (7 July 1823 – 1 May 1907) was an Irish mathematician, economist and poet who started his career as a mathematician. He has been co-credited, along with John William Stubbs, with introducing the geometric concept of invers ...
and George Salmon
George Salmon FBA FRS FRSE (25 September 1819 – 22 January 1904) was a distinguished and influential Irish mathematician and Anglican theologian. After working in algebraic geometry for two decades, Salmon devoted the last forty years of his ...
.
Although he worked mostly on optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
, he is also remembered for his work on geometry
Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
; his most significant work in optics was published in the mid-to-late 1830s; his most significant work on geometry ''On surfaces of the second order'' was published in 1843. He was awarded the Cunningham Medal
The Cunningham Medal is the premier award of the Royal Irish Academy. It is awarded every three years in recognition of "outstanding contributions to scholarship and the objectives of the Academy".
History
It was which was established in 1796 at t ...
of the Royal Irish Academy
The Royal Irish Academy (RIA; ga, Acadamh Ríoga na hÉireann), based in Dublin, is an academic body that promotes study in the sciences, humanities and social sciences. It is Ireland's premier List of Irish learned societies, learned socie ...
in 1838 for his paper on ''On the laws of crystalline reflexion and refraction''. He won the Copley medal for his work on the nature of light in 1842.
MacCullagh was involved with British Association for the Advancement of Science
The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science. Until 2009 it was known as the British Association for the Advancement of Science (BA). The current Chie ...
. He corresponded with many notable scientists, including John Herschel
Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint and did botanical wor ...
and Charles Babbage
Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer.
Babbage is considered ...
. In ''Passages from the Life of a Philosopher'', Charles Babbage wrote that MacCullagh was "an excellent friend of mine" and discussed the benefits and drawbacks of the analytical engine
The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, which was a des ...
with him.
Work on Light and Optics
MacCullagh's most important paper on optics, ''An essay towards a dynamical theory of crystalline reflection and refraction'', was presented to the Royal Irish Academy in December 1839. The paper begins by defining what was then a new concept, the curl
cURL (pronounced like "curl", UK: , US: ) is a computer software project providing a library (libcurl) and command-line tool (curl) for transferring data using various network protocols. The name stands for "Client URL".
History
cURL was fi ...
of a vector field. (The term 'curl' was first used by James Clerk Maxwell in 1870.) MacCullagh first showed that the curl is a covariant vector in the sense that its components are transformed in the appropriate manner under coordinate rotation. Taking his cue from George Green, he set out to develop a potential function for a dynamical theory for the transmission of light.
MacCullagh found that a conventional potential function proportional to the squared norm of the displacement field was incompatible with known properties of light waves. In order to support only transverse waves
In physics, a transverse wave is a wave whose oscillations are perpendicular to the direction of the wave's advance. This is in contrast to a longitudinal wave which travels in the direction of its oscillations. Water waves are an example of t ...
, he found that the potential function must be proportional to the squared norm of the curl of the displacement field. It was accepted that his radical choice ruled out any hope for a mechanical model for the ethereal medium. Nevertheless, the field equations
A classical field theory is a physical theory that predicts how one or more physical fields interact with matter through field equations, without considering effects of quantization; theories that incorporate quantum mechanics are called quantum ...
stemming from this purely gyrostatic medium were shown to be in accord with all known laws, including those of Snell and Augustin-Jean Fresnel
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Isaac Newton, Newton's co ...
.
At several points, MacCullagh addresses the physical nature of an ethereal medium having such properties. Not surprisingly, he argues against a mechanical interpretation of the luminiferous aether
Luminiferous aether or ether ("luminiferous", meaning "light-bearing") was the postulated medium for the propagation of light. It was invoked to explain the ability of the apparently wave-based light to propagate through empty space (a vacuum), so ...
because he readily admits that no known physical medium could have such a potential function resisting only rotation of its elements. "Concerning the peculiar constitution of the ether, we know nothing and shall suppose nothing, except what is involved in the foregoing assumptions ectilinear vibrations in a medium of constant density.. Having arrived at the value of he potential function we may now take it for the starting point of our theory, and dismiss the assumptions by which we were conducted to it."
Despite the success of the theory, physicists and mathematicians were not receptive to the idea of reducing physics to a set of abstract field equations
A classical field theory is a physical theory that predicts how one or more physical fields interact with matter through field equations, without considering effects of quantization; theories that incorporate quantum mechanics are called quantum ...
divorced from a mechanical model. The notion of the ether as a compressible fluid or similar physical entity was too deeply ingrained in nineteenth century physical thinking, even for decades after the publication of Maxwell's electromagnetic theory
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
in 1864. MacCullagh's ideas were largely abandoned and forgotten until 1880, when George Francis FitzGerald
Prof George Francis FitzGerald (3 August 1851 – 22 February 1901) was an Irish academic and physicist who served as Erasmus Smith's Professor of Natural and Experimental Philosophy at Trinity College Dublin (TCD) from 1881 to 1901.
FitzGer ...
re-discovered and re-interpreted his findings in the light of Maxwell's work.
William Thomson, 1st Baron Kelvin
William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician, mathematical physicist and engineer born in Belfast. Professor of Natural Philosophy at the University of Glasgow for 53 years, he did important ...
succeeded in developing a physically realizable model of MacCullagh's rotationally elastic but translationally insensitive ether, consisting of gyrostats mounted on a framework of telescoping rods, described in his paper ''On a Gyrostatic Adynamic Constitution for Ether'' (1890).
Death and legacy
MacCullagh was an idealistic nationalist, in the sense of the time. He unsuccessfully contested the election for the Dublin University constituency in 1847. Suffering from overwork and a bout of depression, he died in 1847 by his own hand in his rooms at Trinity College Dublin. In May 2009, an Ulster History Circle plaque was unveiled at his family tomb at St Patrick's Church in Upper Badoney. The plaque was part of events organised by the Glenelly Historical Society to mark his life.
References
External links
* James MacCullagh'
Collected works
at the Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...
{{DEFAULTSORT:Maccullagh, James
1809 births
1847 deaths
19th-century Irish mathematicians
Academics of Trinity College Dublin
Alumni of Trinity College Dublin
Fellows of the Royal Society
Irish mathematicians
Members of the Royal Irish Academy
Recipients of the Copley Medal
Scholars of Trinity College Dublin
People from County Tyrone
Suicides in Ireland
1840s suicides