b. at S. Giovanni in Marignano, near Rimini, 31 Oct., 1823; d. at Fiesole, 22 Feb., 1885. His early education was received at Rimini from the brothers Speranza, priests. His classical studies he made at the College of the Scolopians at Urbino, of which the distinguished Latin scholar, Father Angelo Bonuccelli, was the rector. He entered their novitiate at Florence, 30 Nov., 1838. From 1840-43 he studied philosophy and the exact sciences at the Ximenian College and observatory, whose rector, the able astronomer and geodete, Father Giovanni Inghirami, was at the same time professor of higher mathematics. Serpieri was only twenty years old when he was appointed instructor in mathematics and philosophy at the college of Siena. Here he became known as a model teacher on account of his lucid style of exposition, his eloquence, and his affable manners. In Nov., 1846, his superior appointed him professor of philosophy and physics at the college of Urbino, while two months later the Papal Government called him also to the chair of physics in the university of the same city. On 27 Aug., 1848, he was ordained priest, and in Nov., 1857, he became rector of the college. He continued in this position and acted at the same time as professor until 1884, when the municipal authorities notified him of the impending secularization of education, both in the primary schools and in the colleges, inviting him however to remain as professor. This unjust decree caused him and his colleagues to give up their positions at the college. The sorrow caused by this event had an almost fatal effect upon his health, which had not been good for some time. Appointed to the rectorship of the Collegio della Badia Fiesolana, he died in the following year after a short illness.

Serpieri's chief merits as an astronomer lay in the observation of shooting stars. His first treatise on this subject dates from 1847 in the "Annali di fisica e chimica" of Maiocchi. In August, 1850, he discovered that the August meteors originate in a radiant not far removed from Gamma Persei (hence "Perseids", Ann. di Tortolino, 1850). In the same year he established an observatory at Urbino, and thereafter published regularly in his monthly bulletin the results of his meteoric observations. These were of great assistance to Schiaparelli in the formulation of his theory on the shooting stars. Serpieri himself expressed some interesting views on this subject in his bulletin in 1867. Urged by Father Secchi, he went to Reggio in Callabria to observe the total eclipse of the sun in 1870, and to ascertain with exactness the northern limit of the zone of totality. The coronal streamers of the sun observable during the eclipse he declared to be sun auroras caused by the electrical influence of the earth and other planets on the sun (Rendic, Ist. Lomb., 1871). When Schiaparelli called his attention to the magnificent work by the American, George Jones, comprising 328 drawings of the zodiacal light as observed at different times and from different places (published at Washington at the expense of the Government), he at once submitted it to a searching analysis. This led him to his theory, in which he explains this phenomenon as light of the earth produced and maintained in the atmosphere by special solar radiations ("La luce zodiacale studiata nelle osserv. di. G. Jones", 138 pp. in "Mem. Soc. Spettr. Ital.", 1876-81).

Serpieri's greatest achievements are in the field of seismology. His study of the earthquake of 12 March, 1873, is, in the opinion of de Rossi, a model of scientific analysis. In this he was the first to introduce the concept of the seismic radiant. The so-called premonition on the part of animals he explains by the hypothesis of a preceding electrical disturbance. His master-work is his study on the earthquake of 17 and 18 March, 1875, which caused great devastation in his home city and in other places. In this study he embodies 240 documents coming from 100 different places, and in it his theory of radiants is proved in a striking manner. He also wrote two memoranda on the terrible catastrophe of Casamicciola. His complete seismological studies, for which he received the gold medal at the General Italian Exposition at Turin (1884), were republished in 1889 by P. G. Giovanozzi. Among his works on physics must be mentioned: a study on the pendulum of Foucault (Ann. Tortolini, 1851); a treatise on the simultaneous transmission of opposing electric currents in the same wire (Corr. sc. di Roma, 1855), a lecture on the unity of natural forces (La forza e le sue trasformazioni, 1868). His work on the electric potential ("Il potentziale elettrico", 171 pp., Milan, 1882), is noted for its system, clearness, and conciseness. It has been translated into German by Reichenbach (Vienna, 1884). His last work, on absolute measures ("Le misure assolute", etc., Milan, 1884), gives in condensed form the principal theories on physics, in particular of electric currents. It has been translated into French by Gauthier-Villars (1886) and into German (Vienna, 1885).

GIOVANOZZI, Della Vita e degli Scritti di Alessandro Serpieri delle Scuole Pie (Florence, 1887), 134 pp.; Allesandro Serpieri, D.S.P., Scritti sismologici nuovamente raccolti e pubblicati da G. Giovanozzi, Direttore dell' Osservatorio Ximeniano (Florence, 1888-89); POGGENDORFF, Biogr. litt. Handwb., iii, 1898, s. v.

J. Stein.