PETTY, Sir william (1623-1687), statistician and political economist, and author of the Down Survey of Irish Lands, was born on 26th May 1623. He was the son of a clothier at Romsey in Hampshire, and received his early education at the grammar-school there. About the age of fifteen he went to Caen (Normandy), taking with him a little stock of merchandise, on which he traded, and so maintained himself whilst learning French, improving himself in Latin and Greek, and studying mathematics and other sciences. On his return to England he seems to have had for a short time a place in the royal navy. He went abroad again in 1643, and remained for three years in France and the Netherlands, pursuing his studies at L r trecht, Leyden, Amsterdam, and Paris. In the last-named city he read Vesalius with the celebrated Hobbes. The philosopher was then preparing his Tractatus Opticus, and it is said that Petty drew the diagrams for him. In 1647 Petty obtained a patent for the invention of double writing, or, in other words, of a copying machine. In politics he espoused the side of the Parliament. His first publication was a letter to Samuel Hartlib in 1648, entitled Advice for the Advancement of some Particular Parts of Learning, the object of which was to recommend such a change in education as would give it a more practical character. In the same year he took up his residence at Oxford, where he was made deputy professor of anatomy, and where he gave instruction in that science and in chemistry. In 1649 he obtained the degree of doctor of physic, and was soon after elected a fellow of Brasenose College. He gained some notoriety in 1650 by restoring to life a woman who had been hanged for infanticide. ïn 1651 he was made professor of anatomy at Oxford, and also became professor of ...music at Gresham College. In 1652 he went to Ireland, having been appointed physician to the army in that country. In 1654, observing that the admeasurement and division of the lands forfeited in 1641 and granted to the soldiers had been (to use his own words) “most inefficiently and absurdly managed,” he entered into a contract to execute a fresh survey, which he completed in thirteen months. By this he gained £9000, and part of the money he invested profitably in the purchase of soldiers’ debentures. He thus became possessor of so large a domain in the county of Kerry that, according to Aubrey, he could behold from Mount Mangerton 50,000 acres of his own land. He set up iron-works in that neighbourhood, opened lead-mines and marble-quarries, established a pilchard-fishery, and commenced a trade in timber. In Macaulay’s History of England there is an account ofthe settlement which he founded at Kenmare. Besides the office of commissioner of distribution of the lands he had surveyed, he held that of secretary to the lord lieutenant, Henry Cromwell, and was also during two years clerk of the council. In January 1658 he was elected to Richard Cromwell’s parliament as member for West Looe in Cornwall. He was accused by Sir Jerome Sankey before the House of Commons of malversation and fraud in the conduct of his survey; but the matter did not come to an issue in consequence of the dissolution of the parliament, and Petty afterwards published tracts in his defence. After the Restoration he returned to England and was favourably received and knighted by Charles II., who was “much pleased with his ingenious discourses,” and who, it is said, intended to create him earl of Kilmore. He obtained from the king a new patent constituting him surveyor-general of Ireland. In 1663 he attracted much notice by the success of his invention of a double-bottomed ship, which twice made the passage between Dublin and Holyhead, but was afterwards lost in a violent storm. He was one of the first members of the Royal Society, and sat on its council. He died at London on the 16th of December 1687, and was buried in the church of his native place. His will, a curious and characteristic document, is printed in Chalmers’s Biographical Dictionary.
Petty was a man of remarkable versatility, ingenuity, and resource. Evelyn declared he had “never known such another genius,” and said of him, “If I were a prince I would make him my second councillor at least.” His character does not seem to have been an elevated one, though Henry Cromwell, who knew him well, appears to have esteemed him highly.
The survey executed by Petty was, somewhat whimsically, called the , ‘ Down Survey,” because the results λvere set down in maps; it is called by that name in Petty’s will. He left in MS. a full account of the proceedings in connexion with it, which was edited by the late Major-General Sir Thomas A. Larcom for the Irish Archaeological Society in 1851. The maps, some of which were injured by a fire in 1711, are preserved in the Public Record Office, Dublin. The survey “stands to this day,” says Larcom, “with the accompanying books of distribution, the legal record of the title on which half the land of Ireland is held; and for the purpose to which it was and is applied it remains sufficient.” Petty’s name is associated with the foundation, or, as it is safer to say, the successful prosecution of what has been somewhat too ambitiously termed “the science of political arithmetic.” It is essentially the same with what is called comparative statistics. In Petty’s time trustworthy numerical expressions of social facts could seldom be directly obtained, and thus large room was left for more or less probable inference from the available data. As we might have expected from his intellectual character, the expedients to which he resorts in seeking to arrive at determinations of this kind are very ingenious, but often unsatisfactory and even delusive. Whilst, however, he sometimes makes too much of the defective materials he could command, he strongly insists on accurate and continued observation as the only sure basis.
Petty was not merely a statistician, he was also a political economist, and one of no mean rank. He is one of the first in whom we find a tendency to a view of industrial phenomena which was at variance with the then dominant mercantilist ideas, and he exhibits a statesmanlike sense of the elements in which the strength of a nation really consists. Roscher names him as having, along with Locke and Dudley North, raised the English school to the highest point it attained before the time of Hume. His Treatise of Taxes and Contributions has been recently pronounced to be “the first great work on economic theory, which it may fairly be said to have founded.” However this may be, it certainly contains a clear statement of the doctrine that price depends on the labour necessary for production. Petty is much concerned to discover a fixed unit of value, and he thinks he has found it in the necessary sustenance of a man for a day. He understands the cheapening effect of the division of labour. He states correctly the notion of “natural and true” rent as the remainder of the produce of land after payment of the cost of production; but he seems to have no idea of the “law of diminishing returns.” He has much that is just on the subject of money: he sees that there may be an excess of it as well as a deficiency, and regards the prohibition of its exportation as contrary to sound policy. But he errs in attributing the fall of the rate of interest which takes place in the progress of industry to the increase in the quantity of money. He protested against the fetters imposed on the trade of Ireland, and advocated a union of that country with Great Britain. Whilst the general tendency in his day was to represent England as in a state of progressive decline— an opinion put forward particularly in the tract entitled Britannia Languens — Petty declared her resources and prospects to be not inferior to those of France.
A complete list of his works is given in the Athcnae Oxonienses. The most important are: the Treatise of Taxes and Contributions (1662, 1667, and 1685); Political Arithmetic, presented in MS. to Charles II., but, because it contained matter likely to be offensive to France, kept unpublished till 1691, when it was edited by Petty’s son Charles; Quantulumcunque, or a Tract concerning Money (1682); Observa tions upon the Dublin Bills of Mortality in 1681, and the State of that City (1683); Essay concerning the Multiplication of Mankind (1686); Political Anatomy of Ireland (1691). Several papers appeared in the Philosophical Transactions. It is much to be regretted, as M , Culloch long since remarked, that a complete and uniform edition of his writings has not been published.
