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Lawrence Parsons, 4th Earl of Rosse

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The Earl of Rosse
19th President of the Royal Irish Academy
In office
Preceded byJohn Kells Ingram
Succeeded byRobert Atkinson
4th Lord Lieutenant of King's County
In office
Preceded byFrancis Travers Dames-Longworth
Succeeded byThe 5th Earl of Rosse
19th Chancellor of the University of Dublin
In office
Preceded byThe 1st Earl Cairns
Succeeded byThe 1st Earl of Iveagh
Personal details
Born(1840-11-17)17 November 1840
Birr Castle, Parsonstown, King’s County, Ireland (now Birr, County Offaly)
Died29 August 1908(1908-08-29) (aged 67)
Frances Cassandra Hawke
(m. 1870)
Children3, including William
Parent(s)William Parsons, 3rd Earl of Rosse
Mary Rosse
RelativesCharles Algernon Parsons (brother)
Alma materTrinity College Dublin
Oxford University
Scientific career
InstitutionsBirr Castle

Lawrence Parsons, 4th Earl of Rosse, KP FRS PRIA (17 November 1840 – 29 August 1908) was a member of the Irish peerage and an amateur astronomer. His name is often given as Laurence Parsons.



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

He served as Chancellor of the University of Dublin between 1885 and 1908. He was Lord Lieutenant of King's County and Custos Rotulorum of King's County from 1892 to his death. He was also a Justice of the Peace for the county and was appointed High Sheriff of King's County for 1867–68.[1] He was knighted KP in 1890.

Lord Rosse also performed some preliminary work in association with the practices of the electrodeposition of copper sulfate upon silver films circa 1865 whilst in search of the design for a truly flat mirror to use in a telescope. However, he found it impossible to properly electroplate copper upon these silver films, as the copper would contract and detach from the underlying glass substrate.[2] His note has been cited as one of the earliest confirmations in literature that thin films on glass substrates experience residual stresses.[3] He revived discussion in on his work Nature's August 1908 edition after witnessing similar techniques used to present newly devised searchlights before the Royal Society.[2]

Although overshadowed by his father (when astronomers speak of "Lord Rosse", it is almost always the father that they refer to), he nonetheless pursued some astronomical observations of his own, particularly of the Moon. Most notably, he discovered NGC 2. In 1880 Otto Boeddicker, a young astronomer from Germany, became his chief assistant.[4]

He was elected a Fellow of the Royal Society in December 1867 and delivered the Bakerian lecture there in 1873. He was vice-president of the society in 1881 and 1887.[5] From 1896 he was President of the Royal Irish Academy. In May 1902 he was at Carnavon 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.[6]

Marriage and children

Birr Castle, County Offaly
Parsons' plaque in Birr Castle

He married Frances Cassandra Hawke, daughter of Edward Harvey-Hawke, 4th Baron Hawke and Frances Fetherstonhaugh, on 1 September 1870. They had three children:


  • "Parsons, Laurence". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/35398. (Subscription or UK public library membership required.)


  1. ^ "Kalgoorlie Miner (WA : 1895 - 1950) Tuesday 1 September 1908-Obituary, Lord Rosse". Trove. Retrieved 4 August 2013.
  2. ^ a b Earl of Rosse (14 August 1908). "Bi-metallic Mirrors made by Electro-Deposition". Nature. 78 (2025): 366–367. doi:10.1038/078366d0. S2CID 4049073.
  3. ^ Hsueh, C.H.; Lee, S.; Chuang, T.J. (January 2003). "An Alternative Method of Solving Multilayer Bending Problems". Journal of Applied Mechanics. 70 (1): 151–154. Bibcode:2003JAM....70..151H. doi:10.1115/1.1526123.
  4. ^ "Lawrence Parsons and Otto Boeddicker". The Linda Hall Library. Retrieved 14 August 2023.
  5. ^ "Library Archive". London: The Royal Society. Retrieved 4 August 2013.
  6. ^ "The Royal visit to Wales". The Times. No. 36759. London. 5 May 1902. p. 10.


Honorary titles
Preceded by Lord Lieutenant of King's County
Succeeded by
Political offices
Preceded by Representative peer for Ireland
Succeeded by
Academic offices
Preceded by Chancellor of the University of Dublin
Succeeded by
Peerage of Ireland
Preceded by Earl of Rosse
Succeeded by