Theatine order, and went to Rome to study theology; and there he was instructed in the mathematical sciences by Le Sueur and Jacquier, the well-known editors of Newton. He then proceeded to Genoa, where he taught philosophy in the Theatine convent; but becoming obnoxious to the inquisition on account of the alleged heretical tendency of some of his doctrines, he fled to Malta, in the university of which he was appointed professor of mathematics by the grand-master Pinto. On the dissolution of the university by the subsequent grand-master, Ximenes, Piazzi returned to Rome, and afterwards obtained in succession various academic appointments in Italy. At length, in 1780, he was appointed by Ferdinand IV., king of the Two Sicilies, to the post, which he held for the remainder of his life, of professor of the higher mathematics at Palermo. In consequence of the king's proposal to found an observatory at Palermo, Piazzi went to France and to England in order to study practical astronomy under the greatest astronomers of the age, and to obtain instruments, for which latter purpose he employed Ramsden. It was at the suggestion of Piazzi that Ramsden for the first time substituted the circle for the quadrant as a means of observing altitudes—a most important improvement, by which various errors are annulled. In 1789 he returned with his instruments to Sicily, and in 1790 he commenced a long course of highly accurate and valuable observations. He devoted his labours in the first instance to the preparation of an improved catalogue of stars; and in so doing he determined the position of each star by means of repeated observations at distant intervals of time. It was owing to this method of observation that on the first day of the nineteenth century he discovered Ceres, the first known of the small planets called asteroids, which revolve round the sun in orbits lying between that of Mars and that of Jupiter. The observations of that body were reduced, and the elements of its orbit calculated, by Piazzi's friend Oriani (q.v.). Ferdinand IV. wished to strike a medal in commemoration of this discovery, but Piazzi prevailed upon him to devote the sum which the medal would have cost to the purchase of an equatorial telescope. He was president of the Academy of Sciences of Naples, foreign associate of the French Institute, and fellow of the Royal Society of London and of various other scientific bodies.—W. J. M. R.
PICARD, Jean, an eminent French mathematician, astronomer, and geodetician, was born at La Flêche on the 21st of July, 1620, and died in Paris on the 12th of July, 1682; according to some authorities, 1683; according to others, 1684. He was priest and prior of Rillé in Anjou. In 1645 he became assistant to Gassendi, whom he afterwards succeeded in the office of professor of astronomy in the collége de France. In 1666 he became a member of the Academy of Sciences. His scientific labours were of very high importance to the progress of astronomy and geodesy. He invented various adjustments and verifications of astronomical instruments, which produced a degree of accuracy of observation unknown before. He reinvented the use of telescopic sights, which had been previously invented by William Gascoygne (q.v.). He was the first to accomplish the measurement of an arc of the meridian with approximate accuracy, and thus to furnish astronomers with a tolerably correct measure of the size of the earth, at the very time when that quantity was about to become of vital importance to the progress of astronomy. He is considered to have been the first inventor of the transit instrument, the most useful of all instruments in a fixed observatory. He proposed the use of the length of the seconds pendulum as a standard of measure. He determined with great precision the amount of the aberration of the fixed stars; but the cause of that phenomenon, viz., the time occupied by the transmission of light across the earth's orbit, was not discovered until a later period.—(See Bradley.)—W. J. M. R.
PICART, Bernard, a French engraver and designer, the son of Etienne Picart, was born at Paris in 1663. A pupil of his father, and also of S. Le Clerc, he at the age of sixteen carried off the prize of the French Academy. He acquired great facility as a designer, as well as an engraver. His separate plates, executed in France, are considered his best. In 1710 he removed with his father to Amsterdam, and thenceforward was employed almost entirely upon book-plates. Many of these are very excellent, but he gradually contracted a careless and inaccurate manner. Of his later prints many are merely of ornamental designs. He was fond of imitating the manner of the earlier engravers, and published a number of plates with their names. After his death seventy-eight of these were published in a collected form under the title of "Impostures Innocentes," folio, Amst., 1734. In all, his prints number about thirteen hundred. Many of them are from his own designs. He died at Amsterdam in 1733.—J. T—e.
PICART, Etienne, called le Romain, a celebrated French engraver, was born at Paris in 1631, and studied at Rome, whence his cognomen. On his return to Paris he was employed on the series of engravings from the collection of the king of France. His prints are very numerous and very unequal. Some are executed only with the graver; in others the needle is also freely used. Many of his prints are from the old masters; some are from contemporary painters; and several are portraits. He was engraver to the king and to the Academy. His last years were spent in Amsterdam, where he died in 1721.—J. T—e.
PICCINI, Nicolo, the musician, was born in 1728, at Bari in the kingdom of Naples, and died at Paris, 7th May, 1800. His father was also a musician, by whom he was destined for the service of the church, and against whose commands he clandestinely studied the art by which he gained his renown. His untaught proficiency was accidentally discovered, and his father was then convinced of the desirability of allowing him to pursue his own strong inclination. This was in 1742, when Piccini was accordingly placed in the conservatorio di S. Onofrio. There he was assigned to the care of one of the primary masters—advanced students of the institution; but the bare formality of explanations he received from this inexperienced teacher was so distasteful to Piccini, that he neglected his exercises, and wrote an entire mass without aid or direction. This breach of discipline was reported to Leo, then the principal of the conservatorio, who rebuked him for squandering the powers of his mind upon a creation which he knew not how to cast into shape, but received him as his own pupil, and gave him daily lessons. Upon Leo's death, Piccini passed into the hands of his successor, Durante, under whom he completed his studies. On quitting the conservatorio in 1754, he wrote his first opera, "Le Donne dispettose," which was given at the minor theatre in Naples, with success that was the more remarkable, because the operas of Logroscino, that had been produced at the same establishment, were so extremely popular as to have precluded, for a long time, the compositions of any other author. The good reception of this work opened the way for others, in which Piccini had the same fortune, and his name thus rose so rapidly, that in 1756 he was commissioned to compose a serious opera, "Zenobia," for the chief theatre. Gaining mastery by every new production, he was enabled to surpass everything he had before accomplished in "Alessandro nell' Indie," which he wrote for Rome in 1758, and its brilliant success induced him to make that city his residence. There he brought out "La Cechina ossia la buona Figliuola," the most popular of all his operas, in 1760. He was engaged to produce a work on an appointed night—one after another, he had refused to set meritless abrettos—the time for the first performance drew near—so, in desperation, he took the text of an opera which had failed, with music by Duni, and in the period of eighteen days he wrote, rehearsed, and ushered his composition into the world. The libretto chosen with such difficulty was adapted by Goldoni from his own comedy of "Pamela," founded on Richardson's novel of the same name. In this opera appears the first example of the continuous finale, the portion of a dramatic work which especially dignifies this class of composition. Logroscino had attempted the embodiment in music of the chief incidents of his action, and so laid the foundation of the design which Piccini developed with admirable effect; but it still remained for Mozart to perfect it, in whose masterly finales we have the greatest models of dramatic construction ever produced. The enormous success of the "Buona Figliuola" prompted the managers of all the theatres in Italy to invite Piccini to write for them, and his prodigious fecundity enabled him to satisfy almost all their demands. As a proof of this may be noted that within seven months, in 1761, he brought out six operas, three serious and three comic, in six different cities. In the year following, he married one of his pupils, whose voice and whose singing were equally matter of admiration for many years. His first reverse of fortune occurred in 1773, when Anfossi—who had studied composition under him, and whom he had most zealously befriended—produced an opera at Rome, which so turned the heads of the notoriously fickle public of that city, that, not content with lauding the work to the utmost, they thought it neces-
