FRISI (PAUL), a profound mathematician and astronomer, was born at Milan the 18th April 1728 ; his family had formerly emigrated from Strasburg, and was established at Milan in an humble station of life.
At the age of fifteen he entered into the convent of the Barnabite friars, or of the congregation of St Paul, where his studies were at first confined to the attainment of some knowledge of geography from the contemplation of the old maps that were pasted on the walls of the galleries ; he soon acquired, however, a taste for geometry, and made consider. able progress in it without an instructor. He was sent to the University of Pavia, to go through a course of divinity, and he did not neglect the op portunity of applying with increased diligence to the mathematics, with the assistance of Professor Olive tano.• He was afterwards removed to Lodi, in order to give lectures there on philosophy; and he soon after distinguished himself by writing a most able Essay on the Figure of the Earth, which, however, he had not the means of printing, as his brethren were unwilling to assist him, until he found a patron for his publication in the Count de Silva, who un dertook to be at the expense of the impression. The credit which he acquired induced some other mem bers of the society to follow his example, and the convent of the Barnabites at Milan soon began to be converted into a nursery of mathematics. His re. potation procured him also, from the King of Sar dinia, the appointment of Professor of Philosophy in the College of Casale : here, however, he thought the conduct of his superiors unjust and tyrannical, and they were also dissatisfied with him on account of his great intimacy with Radicati, whose opinions were rather more liberal than they thought it pru dent to tolerate. This friendship was, however, so far of advantage to Frisi, as it tended to improve his taste in modern literature ; but it was the princi pal cause of his being removed to Novara, where he was obliged to undertake the duties of a preacher. In the mean time, he was nominated a correspond ent of the Parisian Academy of Sciences in 1753, and received similar honours from other scientific bodies. Soon after this he was recalled to Milan, and made Professor of Philosophy in the great Bar nabite college of St Alexander in that city. His dissertation on the Figure of the Earth was very acrimoniously attacked by a young Jesuit, who ac. cused him of being improperly led away by English and French innovations, but it was easy for him to repel so unfounded a charge. From this time he entertained much ill humour against the Jesuits in general, and had written a work to depreciate the order, but lie was advised by his second brother to suppress it. He became, however, more and more connected with the enemies of the Jesuits, and, among them with D'Alembert, Condorcet, and the other Encyclopedistes. He had before this time declared himself, in his lectures, an enemy to the popular opinion of the Italians respecting magic and witchcraft, though he felt himself in some danger of the animadversions of the Inquisition. He was much in the habit of frequenting the best societies in Milan, and even more than was thought consist ent with his religious character ; but he was in some measure emancipated from the restraints of his or der, by his appointment, in 1756, to a professorship in the University of Pisa, for which he was indebted to the Grand Duke Leopold. This situation he re tained for eight years, enjoying the highest degree of credit, and receiving marked attention from all travellers of distinction, and saving, at the same time, a considerable portion of his salary, to which - he added the amount of some prizes which he ob tained from Berlin and Petersburg in 1756, and from Paris in 1758. Notwithstanding his occupa tions as a Professor of Moral Philosophy, he had al ways been in the habit of devoting the greater part of his attention to the mathematical sciences. In 1757 he was made an associate of the Imperial Aca demy of Petersburg, and a foreign member of the Royal Society of London ; in 1758, a member of the Academy of Berlin ; in 1766, of that of Stock.
holm; and in 1770, of the Academies of Copen hagen and of Berne. The Archduke Joseph had sent him, in 1759, a collar with a gold medal, and he received similar marks of distinction from the Kings of Prussia and Denmark. He was also libe rally rewarded by Pope Clement XIII. for his ser vices in arranging a dispute between the people of Ferrara and of Bologna on the subject of rivers and torrents, which had been referred to him on the oc casion of a tour that he made to Naples and to Rome in 1760. The Senate of Venice also made him a proper acknowledgment for the assistance he gave to the commissioners whom they had appoint.. ed to control the ravages of the Brenta. The Em press Maria Theresa settled on him a pension of 100 sequins, or L. 50, a year. He was recalled to Milan in 1764, as Professor of Mathematics in the Palatine schools, with appointments equal to those which he had enjoyed at Pisa, and with the addition.. al advantage of living near his family, and being ena bled to promote their interests. He was at various times much engaged in the decision of controversies respecting canals and rivers, and obtained much cre dit for his skill and ingenuity, though the peculiarities of his temper tended somewhat to increase the number of enemies, which might possibly have been unavoid able. Among other controversies, he was engaged in a dispute respecting the propriety of adding a high pinnacle to the dome of the church at Milan, which has since been raised in opposition to his opinion. In 1766, he undertook a journey into France and England, and his celebrity everywhere procured him the most flattering attentions. At Paris a very libe ral proposal was made to him to remove to Lisbon, but he preferred returning to his own country. In 1768 he went to Vienna, and he was consulted by the government there upon some important ques. tions of ecclesiastical policy, in which his advice was adopted. He remained but little longer in the Col lege of St Alexander, and Pope Pius VI. liberated him entirely from subjection to the superiors of his order, and allowed him to wear the habit of a secu lar priest. As one of the censors of the press, he had incautiously been accessory to the publication of the Lanterna Curiosa, the work of a Coffee house Club in Milan, which gave great offence to the government; and he afterwards still more im prudently undertook to defend it. This circum- . stance occasioned his removal from Milan for a time, but he was recalled in 1777, and was appointed di rector of a school of architecture. He was active in introducing the employment of conductors for se curity against lightning, and had one fixed for an example on the Repository of the Public Archives ; he was equally zealous on every other occasion in the dissemination of useful novelties among his coun trymen. In 1778, he made a tour. into Switzerland, and his observations there gave rise to his specula tions on subterraneous rivers. He enjoyed unin terrupted health until the age of forty-eight, when he was attacked by a haemorrhoids] affection, end ing in an abscess, which, eight years afterwards, re quired the performance of an operation ; this was unfortunately succeeded by a fatal mortification, and he died the 22d November 1784, at the moment when he was about to be placed on the list of the eight foreign associates of the Parisian Academy, an honour which had been delayed by the preference of J. A. Euler, on the occasion of a former vacancy, to the no small mortification of his vanity. He had very lately obtained a prize from the Academy of Heer len], for his Memoir on the Inequality of the Satel lites of Jupiter. He was buried in the church of St Alexander, and a medallion with his portrait was placed over his tomb by his brethren the Barnabites. He had four brothers, Antony, a physician, botanist, and chemist; Antony Francis, an ecclesiastic, au thor of some antiquarian researches of merit; Louis, a canon of St Ambrose, a learned theologian and mechanician ; and Philip, a lawyer, author of a dis sertation, De imperio d jserisdictione.