Gian Domenico Romagnosi, an Italian jurist, born near Piacenza in December, 1761, died in Milan, June 8, 1835. He was chief civil magistrate of Trent, and the Austrians arrested him in 1799 on account of his alleged sympathy with the French, but he was acquitted. During his detention he observed the deviation of the magnetic needle under the influence of a galvanic current. His discovery, published in a journal of Trent in 1802, attracted little attention until the discoveries of Oersted in 1819-'20. He was successively professor of law at Parma, Pavia, and Milan. After the fall of Napoleon he lost his position at the Milan university, but continued to lecture till 1817. In 1818 he was again tried for treason at Venice, and again acquitted. His most celebrated work is Introduzione allo studio del diritto pubblico universale (2 vols., Parma., 1805; 5th ed., Milan, 1836). Complete editions of his writings have been published at Florence (19 vols., 1832 et seq.) and Milan (15 vols., 1836-'45).