Posted by Gemma on the 29th of March, 2012

Joseph Wright, "The Alchymist, in Search of the Philosopher's Stone, Discovers Phosphorus, and prays for the successful Conclusion of his operation, as was the custom of the Ancient Chymical Astrologers". 1771. Possibly based on the discovery of phoshorous by Hennig Brand, whom Patrick Miller has devoted a work to as part of Tribute Night (it's the one with the fog machine). Not visible - the 5000 litres of urine that Brand boiled down to find it.