MERCALLI, GIUSEPPE. — Seismologist and volcanologist, born in Milan on 21 May 1850, died in Naples on 19 March 1914. Ordained a priest in 1871 and graduated in natural sciences in 1874, he taught the subject until 1911 in various schools, including the Liceo di Reggio Calabria and the « Vittorio Emanuele » in Naples. At the same time, on the advice of Stoppiani, his teacher, he began geological research on the glacial terrains of Lombardy. He soon turned, however, to the study of volcanoes and earthquakes, illustrating them in numerous publications, e.g., on the earthquakes of Casamicciola (1883), Liguria (1887), the Pontine Islands (1892), and Messina (1908).
To him are owed the first maps of volcanic Italy and the new classification of earthquakes, which bears the name « M. scale » and is still practically in use, especially for the higher degrees. In 1885 he was appointed privat-docent in seismology and volcanology at the University of Catania and subsequently at Naples; in 1912, director of the Vesuvius Observatory. He suffered a tragic death, being burned to death in a fire inadvertently started by himself in his room. He was a member of several academies, including the Pontifical Roman Academy of the New Lincei.
His publications were numerous; the most noteworthy are: Vulcani e fenomeni vulcanici in Italia (Milan 1883; Pius XI publicly recalled having contributed to it, while still a priest [cf. Neviani, art. cit. in the bibliography], and chapter 11, concerning catalogues of Italian earthquakes, is said to be his); I vulcani attivi della terra, Morfologia, Dinamismo, Prodotti, Distribuzione geografica. Cause (Milan 1907; he describes 213 volcanoes therein).