Hand-coloured etching by Peter Fabris (active 1768-1779). Illustrated plate from William Hamilton's study of Italian volcanoes, 'Campi Phlegraei' (published in Naples, 1776). Specimens of volcanic material removed from a hollow road leading from Pisciarelli to the Solfaterra in southern Italy, showing how acid, sulphureous vapour and rain can affect such material. Based on letters to the Royal Society, Hamilton's book is a seminal work on the nature and effects of volcanic explosions.
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