PETTY, (Sir WILLTAM), a singular in• stance of a universal genius, was the elder son of Anthony Petty, a clothier at Rum. soy in Hampshire, England, where lie was born in the year 1623. While a boy he took great delight in spending his time among the artificers, whose trades he could work at when but 12 years of age. At the age of 15 he was master of the La tin, Greek, and French languages, with arithmetic, and those parts of practical geometry and astronomy useful in navi gation. Soon a!ter he went to the Uni versity of Caen in Normandy ; and after some stay there he returned to England, where he was preferred in the king's navy. In 1643, lie went into the Nether lands and France for three years ; and having vigorously prosecuted his studies, especially in physic, at the Universities of Utrecht, Leyden, Amsterdam, and Paris, he returned home. In 1647, he obtained a patent to teach the art of double writ ing for seventeen years. In 1648, he pub lished at London, " Advice to Mr. Samuel larthb, for the advancement of some par ticular parts of learning." At this time he adhered to the prevailing party of the nation ; and went to Oxffird, where he taught anatomy and chemistry, and was created a Doctor of Physic, and grew into such repute, that the philosophical meet ings, which preceded and laid the foun dation of the Royal Society, were first held at his house. In 1650, he was made Pro fessor of Anatomy there ; and soon after a member of the College of Physicians in London, as also Professor of Music at Gresham College, London. In 1652, he was appointed Physician to the army in Ireland ; as also to three Lord Lieutenants successively, Lambert, Fleetwood, and Henry Cromwell. In Ireland he acquired a great fortune, but not without suspi cions and charges of unfair practices in his offices. After the rebellion was over in Ireland, he was appointed one of the com missioners for dividing the forfeited lands to the army who suppressed it. 'When Henry Cromwell became Lieutenant of that kingdom, in 1655, he appointed Dr. Petty his secretary, and clerk of the council : he likewise procured him to be elected a burgess ffir West Loo in Corn wall, in Richard Cromwell's parliament, which met in January, 1658. But, in March following, Sir Hierom Sankey, member for Woodstock in Oxfordshire, impeached him of high crimes and misde meanors in the execution of his office.
This gave the doctor a great deal of trou ble, as he was summoned before the House of Commons ; and notwithstanding the strenuous endeavours of his friends, in their recommendations of him to Secretary Thurloe, and the defence he made before the Ilouse, his enemies procured his dis mission from his public employments in 1659. He then retired to Ireland till the
restoration of King Charles the Second ; soon after which he came into England, where he was very graciously received by the king, resigned his professorship at Gresham College, and was appointed.one of the commissioners of the Court of Claims. Likewise, April the 11th, 1661, he received the honour of knighthood, and the grant of a new patent, constituting him surveyor-general of Ireland, and was chosen a member of parliament there.
Upon the incorporating of the Royal Society, he was one of the first members, and of its first council. And though he had left off the practice of physic, his name was continued as an honorary member of the College of Physicians in 1663. About this time he invented his double-bottomed ship, to sail against wind and tide, and afterwards presented a model of this ship to the Royal Society ; to whom also, in 1665, he communicated " A Discourse about the Building of Ships," containing some curious secrets in that art. But, upon trial, finding his ship failed in some respects, he at length gave up that pro ject.
In 1666, Sir 'William drew up a treatise, called " Verbum Sapienti," containing an account of the wealth and expenses of England, and the method of raising taxes in the most equal manner. He was well acquainted with the general principles of political arithmetic, and studiously pro moted many projects highly useful to his country. It must, however, be admitted that he was equally attentive to his own interests. Thus, at sixty, he writes that his thoughts were fixed upon improving his lands in Ireland, and to promote the trade of iron, lead, marble, fish, &c. of Which his estate is capable. As for stu dies and experiments, " I think now," says he, " to confine the same to the ana tomy of the people, and political arithme tic; as also the improvement of ships, land carriages, guns, and pumps, as of most use to mankind." Ile died in De cember, 1687, leaving behind him wealth to the amount of about 15,000/. per ann.. His works were very numerous, some of which are well known, and frequently re ferred to by authors in the present day.