He started out as an alchemist, but he began to think in a different way. For example, alchemists thought that everything was made of four things - earth, air, fire, and water. But Boyle found that things are made up of many different elements. In fact, he wrote a definition of what an element is. He said that an element is something that cannot be broken into smaller parts. Boyle is work marked the end of alchemy as a science.