Plate 4, rock specimens found after the 1779 eruption

Plate 4 of the Supplement to Sir William Hamilton, Campi Phlegraei, 'Fields of Flame'. The volume is composed of Hamilton's observations of the volcanic activities of the Vesuvius in 1779.
The plate was painted by British artist Pietro Fabris, who accompanied Hamilton around Mount Etna, Mount Vesuvius, and Lipari islands to document volcanic activities.

Hamilton was the British Envoy Extraordinary to the Kingdom of the Two Sicilies, and took observations of the erupting Vesuvius which he sent to the Royal Society. He was elected to the Society on the merit of his observations in 1766 and received the Copley Medal in 1770 for his 'Account of a Journey to Mount Etna'. The supplement to Campi Phlegraei was composed of observations sent to the then President of the Royal Society, Sir Joseph Banks (1743-1820) and communicated at one of the Royal Society's meeting.