Humphrey Lloyd (physicist)
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Humphrey Lloyd PRIA (16 April 1800 – 17 January 1881) was an Irish physicist and academic who served as the 30th
Provost of Trinity College Dublin The following persons have been provost of Trinity College Dublin. References {{University of Dublin, Trinity College Trinity College, Dublin Trinity College Dublin (), officially titled The College of the Holy and Undivided Trinity o ...
from 1867 to 1881. He was
Erasmus Smith's Professor of Natural and Experimental Philosophy at Trinity College Dublin Erasmus Smith's Professor of Natural and Experimental Philosophy at Trinity College Dublin is a chair in physics founded in 1724 and funded by the Erasmus Smith Trust, which was established by Erasmus Smith, a wealthy London merchant, who live ...
from 1831 to 1843. Lloyd is known for experimentally verifying
conical refraction Conical refraction is an optical phenomenon in which a Ray (optics), ray of light, passing through a Index ellipsoid, biaxial crystal along certain directions, is Refraction, refracted into a hollow cone of light. There are two possible conical r ...
, a theoretical prediction made by
William Rowan Hamilton Sir William Rowan Hamilton (4 August 1805 – 2 September 1865) was an Irish astronomer, mathematician, and physicist who made numerous major contributions to abstract algebra, classical mechanics, and optics. His theoretical works and mathema ...
about the way light is bent when travelling through a biaxial crystal. He was a
Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...
, and President of both the
British Association 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 Chief ...
and the
Royal Irish Academy The Royal Irish Academy (RIA; ), based in Dublin, is an academic body that promotes study in the natural sciences, arts, literature, and social sciences. It is Ireland's premier List of Irish learned societies, learned society and one of its le ...
. Humphrey carried out the
Lloyd's mirror Lloyd's mirror is an optics experiment that was first described in 1834 by Humphrey Lloyd (physicist), Humphrey Lloyd in the ''Transactions of the Royal Irish Academy''. Its original goal was to provide further evidence for the Light#Wave theory, w ...
optic experiments, and was a member of numerous societies in Europe and North America. He also published works relating to religion and the religious identities of Ireland.


Early life

The eldest son of the Very Rev. Bartholomew Lloyd, and his wife, Eleanor McLaughlin, he was born in
Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...
on 16 April 1800. His father had also served as
Erasmus Smith's Professor of Natural and Experimental Philosophy Erasmus Smith's Professor of Natural and Experimental Philosophy at Trinity College Dublin is a chair in physics founded in 1724 and funded by the Erasmus Smith Trust, which was established by Erasmus Smith, a wealthy London merchant, who liv ...
and Provost of Trinity College. After early education at Mr. White's school in Dublin, he entered
Trinity College Dublin Trinity College Dublin (), officially titled The College of the Holy and Undivided Trinity of Queen Elizabeth near Dublin, and legally incorporated as Trinity College, the University of Dublin (TCD), is the sole constituent college of the Unive ...
in 1815, first out of 63 competitors in the entrance examination. He was elected a Scholar in 1818, and graduated B.A. in 1819, taking first place and the gold medal for science, and proceeding M.A. in 1827, and D.D. in 1840. He became a junior fellow in 1824, and a senior fellow in 1843.


Scientific career

Lloyd in 1831 succeeded his father as Erasmus Smith's Professor of Natural and Experimental Philosophy. At the meeting of the
British Association 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 Chief ...
in 1833, he spoke on his establishment by experiment of the existence of conical refraction in biaxial crystals, in conformity with the theory of William Rowan Hamilton. He also succeeded in establishing experimentally the law by which the polarisation of the rays composing the luminous cone is governed. Shortly after, by means of an
experiment An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs whe ...
on the interference of light proceeding directly from a luminous source, with light coming from the same source but reflected at a very high angle of incidence from a plane surface, he contributed to the theory of reflected light. A letter from Sir David Brewster led him to turn his attention to the phenomena of light incident on thin plates. In 1841, he submitted a communication on the subject to the British Association, and in 1859, he described his investigation of the phenomena to the
Royal Irish Academy The Royal Irish Academy (RIA; ), based in Dublin, is an academic body that promotes study in the natural sciences, arts, literature, and social sciences. It is Ireland's premier List of Irish learned societies, learned society and one of its le ...
(see ''Transactions'', vol. xxiv.) When the magnetic observatory of Trinity College Dublin, was established under the auspices of his father, it was placed in Lloyd's charge, and the instruments for it were devised by him and constructed under his superintendence. He was a member of the committee of the British Association lobbying government to improve knowledge of
terrestrial magnetism The ''Journal of Geophysical Research'' is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the u ...
by establishing observing stations. He prepared the instructions for the observatories, and the officers appointed to take charge of them were trained by him in Dublin.


Later life

From 1846 to 1851, Lloyd was president of the
Royal Irish Academy The Royal Irish Academy (RIA; ), based in Dublin, is an academic body that promotes study in the natural sciences, arts, literature, and social sciences. It is Ireland's premier List of Irish learned societies, learned society and one of its le ...
, who in 1862 awarded him their Cunningham gold medal. He resigned his chair of natural philosophy in 1843, on his accession to a senior fellowship in Trinity College. In 1862, he became vice-provost, and in 1867, was appointed provost, in succession to Provost Richard MacDonnell. He was president of the British Association in 1857, when it met in Dublin, and delivered an inaugural address, which was published, in which he gave a sketch of the recent progress made in astronomy, terrestrial magnetism, and other branches of science. Lloyd was a leading member of the general synod of the Irish church which came into existence on Irish disestablishment, and took part in its committee for the revision of the prayer-book. He died in the provost's house, Dublin, 17 January 1881.


Awards and honours

Lloyd was a fellow of the Royal Societies of
London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...
and
Edinburgh Edinburgh is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. The city is located in southeast Scotland and is bounded to the north by the Firth of Forth and to the south by the Pentland Hills. Edinburgh ...
, and an honorary member of many other learned societies of Europe and America. He was elected as a member to the
American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
in 1839. In 1855 the university of Oxford conferred on him the degree of D.C.L., and in 1874 the emperor of Germany the order ''
Pour le Mérite The (; , ), also informally known as the ''Blue Max'' () after German WWI flying ace Max Immelmann, is an order of merit established in 1740 by King Frederick II of Prussia. Separated into two classes, each with their own designs, the was ...
''. A bust of him, by Albert Bruce Joy, was placed in the library of Trinity College in 1892.


Works

In 1834, Lloyd furnished the British Association, at its request, with a report on ''The Progress and Present State of Physical Optics'' (see Report for 1834). Papers which he wrote on terrestrial magnetism and other subjects are in the ''Reports'' of the British Association and in the ''Transactions'' and ''Proceedings'' of the Royal Irish Academy. Besides tracts, his other published works were: * ''A Treatise on Light and Vision'', London, 1831. * ''Two Introductory Lectures on Physical and Mechanical Science'', London, 1834. * ''Lectures on the Wave-theory of Light'', two parts, Dublin, 1836 and 1841; republished, London, 1857, as ''Elementary Treatise on the Wave-theory of Light''. * ''Account of the Magnetic Observatory at Dublin, and of the Instruments and Methods of Observation employed there'', London, 1842. * ''An Account of the Method of Determining the Total Intensity of the Earth's Magnetic Force in Absolute Measure'', London, 1848. * ''The Elements of Optics'', Dublin, 1849. * ''Address delivered at the opening meeting of the British Association for the Advancement of Science, held at Dublin 26 Aug 1857'', Dublin, 1857. * ''Is it a Sin? An Inquiry into the Lawfulness of Complying with the Rule of the National Board relative to Religious Instruction'', published anonymously, Dublin, 1860. * ''The Climate of Ireland and the Currents of the Atlantic'', a lecture, Dublin, 1865. * ''Observations made at the Magnetical and Meteorological Observatory at Trinity College, Dublin'', Dublin, 1865. * ''The University of Dublin in its Relations to the several Religious Communities'', anonymous, Dublin, 1868. * ''The Doctrine of Absolutism'', Dublin, 1871. * ''Treatise on Magnetism, General and Terrestrial'', London, 1874. * ''Miscellaneous Papers connected with Physical Science'', London, 1877.


Family

Lloyd married, in July 1840, Dorothea, only daughter of the Very Rev. James Bulwer, rector of Hunworth-cum-Stody,
Norfolk Norfolk ( ) is a Ceremonial counties of England, ceremonial county in England, located in East Anglia and officially part of the East of England region. It borders Lincolnshire and The Wash to the north-west, the North Sea to the north and eas ...
. He had no children.


See also

*
Physical crystallography before X-rays Physical crystallography before X-rays describes how physical crystallography developed as a science up to the discovery of X-rays by Wilhelm Conrad Röntgen in 1895. In the period before X-rays, crystallography can be divided into three broad are ...


Notes


References

*


External links

* {{DEFAULTSORT:Lloyd, Humphrey 1800 births 1881 deaths Alumni of Trinity College Dublin Fellows of the Royal Society Fellows of Trinity College Dublin Honorary Fellows of the Royal Society of Edinburgh Irish physicists Magneticians Presidents of the Royal Irish Academy Optical physicists Scientists from Dublin (city) Provosts of Trinity College Dublin Recipients of the Pour le Mérite (civil class) Scholars of Trinity College Dublin