Cyrus Pitt Grosvenor (October 18, 1792 – February 11, 1879) was an American Baptist minister known for his anti-slavery views. In his retirement he worked on a famous mathematics problem and took out a patent to prevent lamp explosions.

Cyrus Pitt Grosvenor
BornOctober 18, 1792
DiedFebruary 11, 1879
EducationDartmouth College
OccupationBaptist minister
Known forAnti-slavery, education
Spouse(s)Sarah Warner
Parent(s)Rev. Daniel and Deborah Grosvenor


Cyrus Pitt Grosvenor was born in Grafton, Massachusetts. He graduated from Dartmouth College in 1815.[1] He was a minister for congregations in New Haven, Salem and Boston (1827–40) from 1825 to 1834. Grosvenor was a leader of the anti-slavery movement in Massachusetts and Connecticut, and an agent of the American Anti-Slavery Society. The first meeting of the Essex County Anti-Slavery Society was held at his house.[2]

Isaac Crewdson (Beaconite) writerSamuel Jackman Prescod - Barbadian JournalistWilliam Morgan from BirminghamWilliam Forster - Quaker leaderGeorge Stacey - Quaker leaderWilliam Forster - Anti-Slavery ambassadorJohn Burnet -Abolitionist SpeakerWilliam Knibb -Missionary to JamaicaJoseph Ketley from GuyanaGeorge Thompson - UK & US abolitionistJ. Harfield Tredgold - British South African (secretary)Josiah Forster - Quaker leaderSamuel Gurney - the Banker's BankerSir John Eardley-WilmotDr Stephen Lushington - MP and JudgeSir Thomas Fowell BuxtonJames Gillespie Birney - AmericanJohn BeaumontGeorge Bradburn - Massachusetts politicianGeorge William Alexander - Banker and TreasurerBenjamin Godwin - Baptist activistVice Admiral MoorsonWilliam TaylorWilliam TaylorJohn MorrisonGK PrinceJosiah ConderJoseph SoulJames Dean (abolitionist)John Keep - Ohio fund raiserJoseph EatonJoseph Sturge - Organiser from BirminghamJames WhitehorneJoseph MarriageGeorge BennettRichard AllenStafford AllenWilliam Leatham, bankerWilliam BeaumontSir Edward Baines - JournalistSamuel LucasFrancis August CoxAbraham BeaumontSamuel Fox, Nottingham grocerLouis Celeste LecesneJonathan BackhouseSamuel BowlyWilliam Dawes - Ohio fund raiserRobert Kaye Greville - BotanistJoseph Pease, railway pioneerW.T.BlairM.M. Isambert (sic)Mary Clarkson -Thomas Clarkson's daughter in lawWilliam TatumSaxe Bannister - PamphleteerRichard Davis Webb - IrishNathaniel Colver - Americannot knownJohn Cropper - Most generous LiverpudlianThomas ScalesWilliam JamesWilliam WilsonThomas SwanEdward Steane from CamberwellWilliam BrockEdward BaldwinJonathon MillerCapt. Charles Stuart from JamaicaSir John Jeremie - JudgeCharles Stovel - BaptistRichard Peek, ex-Sheriff of LondonJohn SturgeElon GalushaCyrus Pitt GrosvenorRev. Isaac BassHenry SterryPeter Clare -; sec. of Literary & Phil. Soc. ManchesterJ.H. JohnsonThomas PriceJoseph ReynoldsSamuel WheelerWilliam BoultbeeDaniel O'Connell - "The Liberator"William FairbankJohn WoodmarkWilliam Smeal from GlasgowJames Carlile - Irish Minister and educationalistRev. Dr. Thomas BinneyEdward Barrett - Freed slaveJohn Howard Hinton - Baptist ministerJohn Angell James - clergymanJoseph CooperDr. Richard Robert Madden - IrishThomas BulleyIsaac HodgsonEdward SmithSir John Bowring - diplomat and linguistJohn EllisC. Edwards Lester - American writerTapper Cadbury - Businessmannot knownThomas PinchesDavid Turnbull - Cuban linkEdward AdeyRichard BarrettJohn SteerHenry TuckettJames Mott - American on honeymoonRobert Forster (brother of William and Josiah)Richard RathboneJohn BirtWendell Phillips - AmericanM. L'Instant from HaitiHenry Stanton - AmericanProf William AdamMrs Elizabeth Tredgold - British South AfricanT.M. McDonnellMrs John BeaumontAnne Knight - FeministElizabeth Pease - SuffragistJacob Post - Religious writerAnne Isabella, Lady Byron - mathematician and estranged wifeAmelia Opie - Novelist and poetMrs Rawson - Sheffield campaignerThomas Clarkson's grandson Thomas ClarksonThomas MorganThomas Clarkson - main speakerGeorge Head Head - Banker from CarlisleWilliam AllenJohn ScobleHenry Beckford - emancipated slave and abolitionistUse your cursor to explore (or Click "i" to enlarge) 
Grosvenor is in this painting which shows him at the 1840 Anti-Slavery Convention.[3] Move your cursor to identify Grosvenor (who is behind Galusha) or click icon to enlarge

Grosvenor and Elon Galusha were the two leading Baptist ministers opposing slavery at the time. Grosvenor was a proponent of the anti-slavery Liberty Party.[4] In 1840 he attended the Anti-Slavery Convention in London where he was included in the commemorative painting by Benjamin Haydon, although Grosvenor's face is obscured by Galusha and Henry Sterry. There was a delegation from Massachusetts that included Galusha, George Bradburn, Lydia Maria Child, Harriet Martineau, William Lloyd Garrison, Wendell Phillips and Maria Weston Chapman. In the same year, Grosvenor published a book which investigated the case for whether slavery was scripturally justified by the bible.[5]

Grosvenor was the founding editor of the Baptist Anti-Slavery Correspondent which was first published in February 1841 in Worcester, Massachusetts.[6]

In 1844, Grosvenor led the formation of an American Missionary Society. He was disappointed that Baptist church leaders were unwilling to eject people involved with slavery from the church. He decided that a new organization was required to take a stronger moral position.[4]

In 1849 he was among the founders of New-York Central College, McGrawville in McGraw, New York. He served as its first president.[7]

Grosvenor married Mrs. Sarah Warner and they had three children, but only Sarah Caroline Grosvenor did not die young. Sarah married Baptist Rev. Austin Harman in 1852. When the Harmans moved to Allegan County in Michigan, the Grosvenors followed them. Grosvenor had retired from the college the year after his daughter married. In 1856, Grosvenor’s wife died.[8]


In 1867, Grosvenor applied for a patent for an idea he had to prevent lamps from exploding by using a reservoir of nitrogen.[9] The following year Grosvenor published a study in mathematics relating to the problem of squaring the circle. The problem is an old one and can be stated simply as "Is it possible to construct a square with the same area as a given circle using only a compass and ruler". Grosvenor described a method in a pamphlet titled The circle squared a method for determining the area of a circle squared that as a result gave a value for π (Pi) that was 3.142135… (Pi is 3.14159…).

Square the diameter of the circle; multiply the square by 2; extract the square root of the product; from the root subtract the diameter of the circle; square the remainder; multiply this square by four fifths; subtract the square from the diameter of the circle.[10]

This gave a small but real error. The success of the method was measured by the error only being 0.000543[10] It was later proved (in 1882) that there is no precise geometric method of squaring the circle.[11]

Grosvenor died in Albion, Michigan in 1879 and was buried at the Riverside Cemetery.[8]


  1. ^ Bill, Ledyard. The History of Paxton Massachusetts. p. 111.
  2. ^ Garrison, William Lloyd (1971). A House Dividing Against Itself 1836–1840 (reprint ed.). Harvard University. p. 112.
  3. ^ The Anti-Slavery Society Convention, 1840, Benjamin Robert Haydon, 1841, National Portrait Gallery, London, NPG599, Given by British and Foreign Anti-Slavery Society in 1880
  4. ^ a b Strong, Douglas M (2001), 'Perfectionist Politics: Abolitionism and the Religious Tensions of American Democracy, Syracuse, NY: Syracuse University Press, p. 111.
  5. ^ Grosvenor, Cyrus Pitt (1840). Slavery vs. the Bible: a correspondence between the General Conference of Maine, and the Presbytery of Tombecbee, Mississippi. Spooner & Howland. p. 158. Retrieved 28 November 2010.
  6. ^ Grosvenor, Cyrus Pitt, Richard Fuller, and Elon Galusha. Baptist Anti-Slavery Correspondent. Worcester, Mass: Executive Committee of the American Baptist Anti-Slavery Convention, 1841. p. 2
  7. ^ Passic, Frank. "Cyrus Pitt Gosvenor". Albion Historical Society Collection. Retrieved 28 November 2010.
  8. ^ a b "Widow of Abolitionist in Taylor cemetery". Saugatuck-Douglas Historical Socienty. Archived from the original on 28 July 2011. Retrieved 28 November 2010. Cite uses deprecated parameter |deadurl= (help).
  9. ^ Cyrus P. Grosvenor U.S. Patent 71,872 "Improvement in the mode of preventing explosion of lamps", December 10, 1867
  10. ^ a b Berggren, Lennart; Jonathan M. Borwein; Peter B. Borwein (2004). Pi, a source book. p. 300. Retrieved 1 December 2010.
  11. ^ "Carl Louis Ferdinand von Lindemann". The MacTutor History of Mathematics archive. St. Andrews University. Retrieved 30 November 2010.