The discovery of extinct volcanoes in the 18th century and the anthology on volcanoes by Giovanni Targioni Tozzetti (1779)

Paolo Sammuri¹
sup>1Accademia dei Fisiocritici, Piazzetta Silvio Gigli 2 (già Prato di Sant'Agostino).
Corresponding author e-mail: science.sam@tiscali.it

This work aims to develop the knowledge of the last work of Giovanni Targioni Tozzetti, his book on volcanoes of 1779. The main objective of Targioni was to affirm the priority in the discovery of extinct volcanoes of his master Pier Antonio Micheli. In this book, in addition to two of his essays, Targioni presents an anthology of the volcanology of his time, however with a rather partial selection of authors. For this reason, in this study it has been considered useful to present a more extensive panorama of the level reached by volcanological knowledge in the eighteenth century, starting from the precursors of the seventeenth century. The large number of authors cited allowed only their basic ideas to be presented, which could later influence Targioni’s vision. The “fomite” theory of Targioni is examined, which explains the activity and extinction of volcanoes based on the observation of the behavior of Tuscan geothermal phenomena. The limits of petrographic observation are then shown, which starts from the examination of samples of rocks in his and other collections and interprets volcanic rocks as formed underground for high-temperature firing from normal rocks. The Targioni’s choices are discussed, his geological intuitions and his mistakes.

Volcanology, XVIII century, Targioni Tozzetti, Tuscany, Italy.