Lazzaro Spallanzani and his geological travels to the "Due Sicilie": the volcanology of the Aeolian Islands

Lazzaro Spallanzani (1729-1799) is certainly one of the most interesting and prominent figures in late eighteenth century Italian science. A significant part of the results of his geological researches were published in the first five volumes of the Viaggi alle Due Sicilie e in alcune parti dell'Appennino (Pavia, 1792-1797, in 6 volumes), which contained the reports of several travels in southern Italy (Kingdom of Two Sicilies) and in the northern Appennines (between Modena and Reggio Emilia) during the years 1788, 1789 and 1790. This impressive work was also translated in the main European languages: German (1794-96), French (1795-96) and English (1798). During his travels Spallanzani paid particular attention to volcanic phenomena, as he had the possibility to observe directly Vesuvius and the Vesuvian area, to climb Mount Etna and to study in detail the Aeolian Islands. Concerning the latter, it is very interesting to notice that Spallanzani devoted all the second volume (1792) and about half of the third (1793) to the analysis of the geological and volcanological feautures of Lipari, Stromboli, Vulcano and other parts of the Aeolian Islands. This wide treatment is rather significant if we recall that the reports on Etna, Vesuvius and the Vesuvian area were completely confined to only one volume of the Viaggi (the first volume, published in 1792). The aim of this paper is to provide an account of Spallanzani's studies on the volcanology of the Aeolian Islands. These researches especially followed those by William Hamilton and Déodat de Dolomieu on the same subject and represented an important stage in the development of Spallanzani's volcanological theory