Specimens of a curious volcanic matter taken from a hollow road leading from Pisciarelli to the Solfaterra, Plate XXXXIII, from 'Campi Phlegraei: Observations on the Volcanoes of the Two Sicilies', by Sir William Hamilton (1730-1803), published 1776 (hand coloured engraving).
Crédit:
Album / Heritage Images / Historica Graphica Collection