Jābir ibn Hayyān, known as “Geber” in Western texts, was probably the world’s first alchemist to run actual experiments. Jābir lived during the eighth century in what is now Iran, and like alchemists before and after him, was fascinated by the prospect of changing one metal into another and by creating artificial life. To Aristotle’s four elements, Jābir added sulfur and mercury, and proposed that all metals were made of differing ratios of these two elements. He was the first to emphasize the importance of rigorous experimentation and is credited with describing many common lab techniques and equipment.