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Petty, William

1. Dates
Born: Romsey, Hampshire, 26 May 1623
Died: London, 16 Dec. 1687
Dateinfo: Dates Certain
Lifespan: 64
2. Father
Occupation: Artisan
Anthony Petty was a cloth worker and taylor; he owned his own home and probably some farm land.
Aubrey states that he left little or no estate, and most biographers conclude that he was poor. It is worth noting, however, that William Petty owned a house in Romsey, presumably the paternal one. On the other hand, William went to sea at age fifteen as a cabin boy. On the whole, I conclude that the father was poor.
3. Nationality
Birth: English
Career: English
Death: English
4. Education
Schooling: Utrecht, Leiden, Oxford
When stranded in Caen in the 1630s, Petty studied for a year with the Jesuits.
Studied Medicine at Utrecht, Leiden, Amsterdam, and Paris, 1643-46. He matriculated in Leiden in 1644, and I think there would have been no place to study medicine in Utrecht except the university. Amsterdam is another matter; virtually nothing is said about it. It seem clear that in Paris Petty studied outside the university. No evidence of B.A. and every reason to think there was none. He is one of two in this catalogue for whom I will list an M.D. without a B.A. or its equivalent.
He went to Oxford about 1648 to study medicine. M.D., 1650.
5. Religion
Affiliation: Calvinist, Anglican
Romsey was a Puritan town; Petty stood on the Parliamentary side in the Civil War (though he avoided military service), and he thrived under the Commonwealth. I think that I must assume he began as a Puritan, even though there is no evidence of it that I know of. He certainly conformed upon the Restoration.
Petty was hardly a religious man, though in that age he inevitably wrote some on religious topics--including a much admired Latin metrical rendition of Psalm 104. He was virulently anti-clerical, apparently of whatever denomination.
6. Scientific Disciplines
Primary: Demography, Geography, Cartography
Subordinate: Anatomy, Natural Philosophy
Petty was a general virtuoso who was intimately associated with the partisans of the new natural philosophy who organized the Royal Society. His central area of intellectual activity was what we would call economics, of which he is seen as virtually the original source. He was the first writer on these topics who attempted to base his conclusions on statistical data, and in general (reflecting the influence of the new natural philosophy) he liked to talk about applying number, weight, and measure to such questions. Treatise of Taxes and Contributions, 1662. Verbum sapienti, c. 1665 (published 1691) contains the first estimate of national income. Political Anatomy of Ireland, c.1672 (published 1691) advocates an economic policy supported by economic geography. Political Arithmetick, c. 1671-6 (published 1690).
He was closely associated with John Graunt and his Natural and Political Observations, 1662, which started the sciences of demography and statistics. Some have claimed that Petty was really the author, but this is not generally accepted. Petty was, however, the author of ten essays on the populations of London, Dublin, Paris, Rome, and other cities. Petty was one of the extraordinary intellects of the age; aside from demography, his most productive areas fell outside the precincts of this study.
His general map of Ireland, published in Hiberniae delineatio, 1684, which stemmed from the Down Survey, occupied much of his time between 1660 and 1678. It is received as the foundation of modern Irish geography. I do not see how clearly to separate it from cartography, and I list both.
Anatomical questions occupied him early on. He was known as a skilled preparer of anatomical specimens, and Landowne affirms that a fair number of what he calls medical (and I interpet as anatomical) manuscripts survive.
In 1674 he delivered A Discourse to the Royal Society Concerning the Use of Duplicate Proportion, published as a separate pamphlet that year. It is an exercise in the new mechanical philosophy.
7. Means of Support
Primary: Government, Personal Means, Medicine
Secondary: Academia, Schoolmastering, Patronage
Went to sea as a cabin boy; later served in the navy, 1638- 42.
According to Petty, when deposited in Caen, c.1639, he supported himself by giving lessons in English and navigation, and by petty trading.
It is quite unclear how he supported himself (and his younger brother) on the continent in the period 1643-6. He had superb confidence and a knack for getting by. Strauss suggests that he worked as a journeyman jeweller while he studied. When he returned to England in 1646, he pursued his father's trade as a clothier for a time, and devoted himself to mechanical improvements in textile processes.
When Evelyn first met Petty, c. 1647, he was tutor to a neighbor of Evelyn.
He apparently also earned money by preparing anatomical specimens.
Soon after he went to Oxford he became a fellow of Brasenose College and then vice-principal; Professor of anatomy at Oxford 1650. He left Oxford very soon, but he retained the fellowship until 1659.
Professor of Music at Gresham College, 1651; he retained this position until 1660.
Physician-general to Cromwell's army in Ireland, and personal physician to the commander, 1653-9. Salary of 400 plus the right of private practice.
He received a large payment for his land survey in Ireland, the Down Survey, (more than 13000), 1655-6. He also arranged to get a very large estate for himself.
Personal secretary to Henry Cromwell, the effective governor of Ireland, and Clerk of the Council, 1655-9. In 1656 he was appointed to the Commission to distribute forfeited lands, and with the other commissioners absent he virtually was the Commission.
Petty became very wealthy during the Commonwealth, and lived thereafter on his personal wealth. Petty never got a significant position, though he coveted one, during the Restoration. He did become Registrar to the Irish Court of Admiralty in 1676, and for a time he was a Commissioner of the Navy in England. He became quite bitter about his effective exclusion from power.
8. Patronage
Types: Government Official, Merchant, Aristrocrat, Court Official, Gentry
I have not found who stood behind Petty's initial appointments--at Oxford and then in Ireland. The whole of his future career hung on them; I assume they were political figures in the Puritan regime.
We are told that John Graunt was the key figure in Petty's appointment at Gresham College.
Sir Hardress Waller strongly supported Petty's land survey in Ireland. Waller's daughter became Petty's wife much later.
In Ireland, he gained the support of Henry Cromwell.
At the Restoration Petty apparently had the support of the Duke of Ormond, the most powerful man in Ireland and for a time the Lord Lieutenant, and this support was crucial to Petty's success in retaining his estate. He soon alienated Ormond, however, and from that time Ormond helped to thwart Petty's higher ambitions.
Ormond introduced Petty to Charles, whom Petty charmed (though he also aroused suspicions apparently). In any event, Charles knighted him in 1661 when it was clear that Petty accepted the Restoration, and Charles, by royal letter, confirmed him in his estate. Petty was twice offered peerages, but refused both times.
James II also valued him, and shortly before his (James') flight from England, as a tribute to Petty's memory, he raised Petty's widow and eldest son to the peerage as Baroness Shelburn and Lord Shelburn.
Petty hardly used the device of dedications. This applies also to the maps in Hiberniae delineatio. The only dedication I have found was his Discourse Concerning Duplicate Proportion, 1674, which he dedicated to both William Cavendish (in a dedication looking back to the time in Paris in the 40s) and Lord Brouncker. Neither was in a position to aid Petty's career, and I don't consider the two dedications as part of the system of patronage. Petty did put the royal arms of England and of Ireland on the title page of the Delineatio and he did get a royal privilege for the book (which he valued at 100 per annum in his will).
Patronage, which was so kind to Petty at the beginning of his career, deserted him when he was wealthy and wanted an official position. His papers are apparently full of his scorn for the arts of the courtier. The lack of dedications is surely revealing. He refused to compromise the radical policies he kept advocating. And he grew bitter from his exclusion, even though he was largely responsible for it.
9. Technological Involvement
Types: Cartography, Mechanical Devices, Navigation, Medical Practice
The Down Survey and the later map of Ireland.
What he called a double-writing instrument, c.1646. He invented miscellaneous other things, such as a mechanical grain planter. There were also inventions associated with dying and cloth making. He had hopes of supporting himself by his inventions. Later he contributaed papers on applied mechanics and practical inventions to the Royal Society, and he proposed fixing an engine (not described) with propelling power to a ship. He devised a new carriage.
Designed and constructed three twin-hulled ships 1662-4 and 1684. He delivered a discourse on building ships to the Royal Society.
Medical practice.
Although I do not know how to categorize it, Petty set up an industrial colony, making iron among other things, on his estate in Kerry. The colony thrived until the Catholic reaction destroyed it about 1687.
10. Scientific Societies
Memberships: Royal Society, Medical College Informal Connections: Friendship with Hobbes and Sir Charles Cavendish in Paris, and Samuel Hartlib and John Pell later in London. For Hartlib he wrote a pamphlet on education in the Baconian tradition. Acquaintance with John Evelyn.
Connection with Oxford group which met originally in Petty's lodgings.
Royal College of Physicians, 1651.
Royal Society, 1660; Petty was part of the group that initiated the Society. He was named to the original Coundil specified in the first charter; frequently on the Countil thereafter and vice-president, 1673.
In Dublin he endeavored to organize a similar society, the Dublin Society, in 1684.
  1. Dictionary of National Biography (repr., London: Oxford University Press, 1949-50), 15, 999-1005. John Aubrey, Aubrey's Brief Lives, ed. O.L. Dick, (London, 1949), pp. 237-41.
  2. Geoffrey Keynes, A Bibliography of Sir Willaim Petty F. R. S., (Oxford, 1971).
  3. Edmund George Petty Fitzmaurice, The Life of Sir William Petty, 1623-1687, (London, 1895).
  4. Eric Strauss, Sir William Petty: Portrait of a Genius, (London, 1954). Charles Henry Hull, "Petty's Life," in Hull ed. The Economic Writings of Sir William Petty, 2 vols. (Cambridge, 1899), 1, xiii-xxxiii.
  5. Lord Lansdowne, "Introduction," in Lansdowne, ed. The Petty Papers, 2 vols. (London, 1927), 1, xiii-xl.
  6. Robert Kargon, "William Petty's Mechanical Philosophy," Isis, 56 (1965), 63-6.
  7. Alessandro Roncaglia, Petty: The Origins of Political Economy, tr.
  8. Isabella Cherubini, (Armonk, NY, 1985).
Not Available and Not Consulted
  1. Tony Aspromourgos, "The Life of William Petty in Relation to His Economics: A Tercentenary Interpretation," History of Political Economy, 20 (1988), 337-56.
  2. Irvine Massson, "Sir William Petty, F.R.S." Notes and Records of the Royal Society, 15 (1960);, 79-90.
Compiled by:
Richard S. Westfall
Department of History and Philosophy of Science
Indiana University

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1995 Al Van Helden
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