The discovery of phosphorus was made when an alchemist, Hennig Brand, tried to make gold from urine. It’s something that most people wouldn’t even think of trying to do, but back in the mid seventeenth century peoples general knowledge of chemistry was not as advanced as it is today. So why did he try to make gold from urine?
In 1669 an alchemist called Hennig Brand noticed that urine and gold were basically the same colour. He reasoned that the reason urine was the colour it is is because it contains gold, a highly precious metal. So what should a good alchemist do with such a hypothesis? Make the theory a reality.