Mount Vesuvius' crater, Kingdom of Naples, 1767.

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). The interior of Vesuvius' crater c1756, showing (1) a smaller mountain formed within the crater of the 'Little Mountain', and streams of lava. Based on letters to the Royal Society, Hamilton's book was a more precise study of volcanic activity than had previously existed, illustrating his claim that volcanoes are creative natural forces.