Three Persons Viewing the Gladiator by Candlelight (1765) by Joseph Wright. An Experiment on a Bird in the Air Pump (1768) by Joseph Wright. Courtesy Derby MuseumsThe Alchymist, in Search of the Philosopher’s Stone, Discovers Phosphorus (1771) by Joseph Wright. Courtesy Derby MuseumsTravelling lecturers in fact used something called a ‘lungs-glass’ that replicated this without the need for animal sacrifice. Detail from the Air Pump (1768) by Joseph Wright.