Although we now know that the foundation Alchemists relied on was false. (That everything on Earth was made of four elements) They made some significant contributions to the atomic theory, and the study of chemistry. Alchemists classified the Aristotelian elements with four basic qualities. “Hotness, Coldness, Dryness, Moistness.” It was thought that every metal displayed two of these qualities on the interior and the exterior. For example, lead was cold and dry, while gold was hot and moist. They theorized that changing the qualities would change the metal. It was also interesting to Muslim alchemists that the noblest metal could be dissolved using a mixture of nitric and hydrochloric acids.