Phosphorus Discovered

In 1669, the Hamburg merchant and amateur alchemist Hennig Brand isolated a pale, waxy substance that glowed in the dark. He had discovered phosphorus, and it is generally regarded as the first element whose discovery can be credited to a named person in the modern era. Earlier elements such as gold, iron, and sulfur had been known since antiquity, with no identifiable discoverer. Brand's find is also remembered as a bridge between alchemy and the emerging science of chemistry.

Brand worked in a period when alchemists still searched for the philosopher's stone, a substance thought to turn base metals into gold. Little is firmly known about his life. He is said to have been a former soldier who married into money and later devoted himself to experiments. Like many alchemists, he looked for valuable materials in unlikely places, and he reportedly turned to human urine, which he thought might hold the "spirit" of gold because of its color. Historians note that the reasoning behind his choice is poorly documented and partly reconstructed from later accounts.

According to those accounts, Brand collected large quantities of urine, let it stand until it putrefied, and then boiled it down to a thick paste. He heated this residue to very high temperatures and distilled the vapors. What condensed was a white material that shone with a steady, ghostly light and sometimes burst into flame in air. The glow was caused by the slow oxidation of phosphorus. The name comes from Greek words meaning "light-bearer." Brand kept his method secret and tried to sell it, which was typical of alchemists who hoped to profit from their knowledge.

The secret did not stay secret for long. The German chemist Johann Kunckel and others learned of the process, and Kunckel worked out a version of it independently. The Irish scientist Robert Boyle also produced phosphorus in the early 1680s and published a more open description of its preparation. Boyle's assistant, Ambrose Godfrey Hanckwitz, later made a business of manufacturing it. For a time the material was a costly curiosity, displayed in learned circles as a marvel.

The longer-term importance of phosphorus was considerable. In the 18th century, researchers found it in bones, and a method for extracting it from bone ash made production far cheaper. Later it became central to the manufacture of matches, fertilizers, and many industrial chemicals. Biologists eventually showed that phosphorus is essential to life, forming part of DNA and the energy-carrying molecule ATP. Brand never found the philosopher's stone, but his search yielded one of the most consequential discoveries in the early history of chemistry.