After his return to Milan ho was chiefly employed in miniature painting, until he was ordered by Napoleon I. to make an engraving of Gros's portrait of him ; and he was appointed about the same time (1798) to succeed Vangeliati, deceased, as professor of engraving in the Academy of the Brera, to which, during Longhes professorship, many distinguished engravers of the present time in Italy owe their education. It was one of Longhre first principles to make the means subservient to the end, and not the end to the means; ha always deprecated cleverness of line as a principal object, and in his own works manual dexterity is invariably subordinate to conformity of style. His first object was to give, as nearly as possible, the general character, colour, and texture of the original, and the etching-needle was accordingly his chief instrument. He excelled in light and shade. Among his principal works are—the ' Vision of Ezekiel,' after Raf faelle; the 'Spoealizio, or the Marriage of the Virgin,' and a ' Holy Family,' after the same ; the 'Entombment,' after D. Crespi ; the ' Magdalen,' after Correggio; the 'Madonna del Lego,' after Da Vinci ; 'Galatea,' after Albani ; and many heads, after Rembrandt. The Sposalizio ' was engraved as a companion-piece, or pendant, to Morghen'e large print of the Transfiguration,' by Raffaelle. He commenced in 1827 to engrave the 'Last Judgment,' by Michel Angelo, from a drawing by the Roman painter Minardi, but he died before it was quite finished. Longhi died of apoplexy in 1831. He was a Knight of the Iron Crown, and member of many academies. Pesidea a few poems and other essays, there is a treatise on engraving by Longhi ('La Calcographia'), which has been translated into German by C. Barth, and contains a life of the author by F. Lougheua. A life of him also, with a list of his works, was published at Milan in 1831 ; and there are notices of him in the Kunstblatt,' and in Nagler'.' Neues Allgerneines Kiinetler-Lexicon.' LONGVNUS, the author of a treatise in Greek On the Sublime, is said to have been born either in Syria or at Athens, but at what time is uncertain. His education was carefully superintended by his uncle Fronto, a celebrated teacher of rhetoric ; and he also received instruction from the most eminent teachers of philosophy and rhetoric of his age, especially from Ammonius and Origen. Ho afterwards settled at Athens, where ho taught philosophy, rhetoric, and criticism to a numerous school, and numbered among his disciples the celebrated Porphyry. His school soon became the most distinguished in the
Roman empire. After remaining at Athens for a considerable time, he removed to Palmyra at the invitation of &amble, in order to super intend the education of her sons. He did not however confine his attention to this duty, but also took au active part in public affairs, and is said to have been one of &noble), principal advisers in the war against Aurelian, which proved so unfortunate to himself and his royal mistress. After tho capture of Palmyra by Aurelian &.D.273, Longinus was put to death by order of the emperor.
Longinus wrote many works on philosophical and critical subjects, now known only by their titles, none of which have oome down to us, with the exception of his treatise Gn the Sublime,' and a few frag ments preserved by other writers. There is however some doubt whether the treatise On the Sublime' (repl Nrous) was iu reality written by this Longinus. Modern editors have given the name of the author of this treatise as Dionysius Longinus ;' but in the best manu scripts It is said to be written by Dionyslus, or Longinus, and In the Florence manuscript by an anonymous author. Suidas says that the name of the counsellor of Zenobia was Longinus Cassius. Some critics have conjectured that this treatise was written by Dionysiue of Hall carnassus, or by Dionysius of Pergamum, who is mentioned by Strabo (625, Casaub.)as a distinguished teacher of rhetoric; but the difference of style between this work and the acknowledged works of Diouysius of Halicarnassus renders this conjecture very improbable, and as to the other Dionysius, the conjecture has no foundation. The treatise On the Sublime has for its object the exposition of the nature of the sublime, both as to the expression and the thought, which the author illustrates by examples. As a specimen of critical judgment the work has always maintained a high rank, and iu point of style is perspicuous and precise.
The best editions of Longinus are by Pearce (1724), Mortis (1769), Toup (1778), with improvements by Ruhnken (Oxford, 1806), 1Veiske (1809), and Eggerix (1837); the best translations are the German by Schlosser, the French by Boileau, and the English by W. Smith.