thumb|The fox in Basil Valentine's Third Key represents aqua regia, Musaeum Hermeticum, 1678 The third of Basil Valentine's keys () shows a dragon in the foreground and a fox eating a rooster in the background. The rooster symbolizes gold (from its association with sunrise and the sun's association with gold), and the fox represents aqua regia. The repetitive dissolving, heating, and redissolving (the rooster eating the fox eating the rooster) leads to the buildup of chlorine gas in the flask. The gold then crystallizes in the form of gold(III) chloride, whose red crystals Basil called "the rose of our masters" and "the red dragon's blood". pp. 149-153. The reaction was not reported again in the chemical literature until 1895. Cf. .
thumb|the fox in basil valentine's third key represents aqua regia musaeum hermeticum 1678 the third of basil valentine's keys () shows a dragon in the foreground and a fox eating a rooster in the background the rooster symbolizes gold (from its association with sunrise and the sun's association with gold) and the fox represents aqua regia the repetitive dissolving heating and redissolving (the rooster eating the fox eating the rooster) leads to the buildup of chlorine gas in the flask the gold then crystallizes in the form of gold(iii) chloride whose red crystals basil called "the rose of our masters" and "the red dragon's blood" pp 149-153 the reaction was not reported again in the chemical literature until 1895 cf 