Hand-coloured etching by Peter Fabris (active 1768-1779), after his own drawing. Illustrated plate from William Hamilton's study of Italian volcanoes, 'Campi Phlegraei' (published in Naples, 1776). Part of the hollow road leading from the Grotto of Pausilipo (now known as Posillipo) to Pianura, showing Peperino stone quarries, a rock of volcanic origin harder than tufa but softer than lava. 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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