The picture, oil on canvas, by Joseph Wright of Derby (1734 – 1797), first exhibited in 1771 with the original full title of “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” (derbymuseums.org, 2014).
Joseph Wright was an English landscape and portrait painter, who was “the first professional painter to express the spirit of the Industrial Revolution”.
Just as astrology – study of cosmic objects alleged influence on human life – was a forerunner of astronomy, alchemy was a predecessor of chemistry. Alchemy studied ways to obtain a magical substance, Philosopher’s Stone, which was supposed to be a source of eternal youth and, as a side effect, converted common, cheap metals such as lead to gold.
“Alchemist discovering phosphorus” is the Wright’s depiction of a real event. In 1669 German alchemist Henig Brand after collecting and evaporating human urine discovered a waxy substance emitting white light. Later, analysis has shown that the substance was a chemical element, phosphorus.