Lava strata from Mount Vesuvius, Kingdom of Naples, c 1767.

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). Image shows the thick strata of lava that ran down into the sea from Vesuvius in the large eruption of 1631, and which became the principal quarry for stone used to pave Naples' streets. Based on his letters to the Royal Society, the book illustrates Hamilton's claim that volcanoes are creative natural forces.