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 (4, 7) lava, (2) honey comb pumice and (11,12,13,14) pumice stones of different tints discovered by Hamilton in the region of Mount Vesuvius. Based on letters sent to the Royal Society, Hamilton's book was a more precise account of volcanic activity than had previously existed.
© Science Museum / Science & Society Picture Library