In 1669, an alchemist’s unusual search for gold led to one of chemistry’s strangest discoveries

Throughout history, there have been many scientific discoveries that began as mistakes. Few are, however, as strange as the discovery of phosphorus.In 1669, a German alchemist named Hennig Brand spent months preparing large amounts of urine, hoping to produce gold, but instead produced a glow-in-the-dark, waxy substance unlike anything previously seen.Brand never found the Philosopher's stone, but in its place discovered the first recorded isolation of elemental phosphorus, which is seen by historians of science as a significant moment in the shift from alchemy to modern chemistry.The search for gold, which led somewhere elseBrand lived in Hamburg during a time when alchemy was still viewed as an interesting mix of mysticism and experimentation.He, along with many others working during that time, believed that certain substances could be transformed into even more precious substances. According to a 2024 review published in Medical Research Archives and archived by PubMed Central, Brand isolated phosphorus in 1669 while on the pursuit of alchemical gold. It was not a conscious decision on his behalf to discover a new element; rather, he was pursuing the centuries-old quest of transmutation.The failed search for gold became one of chemistry’s famous accidental discoveries.Why urine?Perhaps the strangest part of the story is the substance which Brand chose to work with.According to reports, the alchemist used dozens of buckets of urine while trying to find the key to making gold. Urine attracted the attention of some alchemists because of its colour and because it was thought to contain concentrated substances produced by the human body. Brand boiled down several large amounts of urine into a thick, dark paste and then heated the mixture intensely, hoping that valuable elements would appear, but instead, a strange, glowing substance was formed.This process included concentrating urine into a paste and heating it with sand. The element that appeared to make its own lightIt was not only that phosphorus was a new element, but it also possessed unique qualities compared to anything else found at that time. This glowing substance emitted a dim light when in contact with the air, and its name is believed to come from the Greek word phosphoros, meaning 'light bearer'.During an era when light sources consisted mainly of oil lamps and candles, such a discovery would have appeared revolutionary.The glow observed by Brand was real, though it has to be said that illustrations tend to overemphasise its strength, and the pure element that was isolated was white phosphorus, which glows slightly when exposed to air, due to slow oxidation.A turning point from alchemy to chemistryHistory commonly refers back to Brand's discovery for the very reason stated above. Even though he was an alchemist, the element he found could be experimented with, classified, and studied further.In the eyes of historians, Brand's work signifies the start of a move away from mystical experimentation and towards the properties of matter.A review by the Royal Society of Chemistry argues that this work led to the development of phosphorus chemistry and is one of the founding contributions to modern science. Over time, scientists were able to find that phosphorus is also found in plants and animals, but initially, it was viewed as merely a curious novelty that was extracted from urine.An accidental discovery that still mattersMore than 350 years later, this still remains one of the most talked-about of scientific discoveries.Although the experiment was messy and failed in its original goal, he produced the first recorded isolation of a chemical element, a discovery often regarded as an important milestone in the transition from alchemy to modern chemistry. This is an example of the fact that scientific progress does not have to take a logical progression.Sometimes important breakthroughs can be discovered as a result of flawed assumptions, unpredictable outcomes and determination on behalf of the scientist. In the case of Brand, a quest to discover a mythical element led to the discovery of an altogether new element, which ultimately helped to bring science into the modern era.