The philosopher who wrote his extant works, "Purification" and "On Nature," in hexameter verse after Parmenides was Empedocles. Empedocles was a Greek philosopher and scientist who lived in the 5th century BCE. He is known for his contributions to the development of the atomic theory and his theories about the nature of the universe and the elements. "Purification" and "On Nature" are two of Empedocles' most famous works, and they are written in hexameter verse, which was a common poetic form used by the ancient Greeks. In these works, Empedocles discusses his theories about the nature of the universe and the elements, and he also explores the concept of purification, which he believed was necessary for achieving a state of spiritual enlightenment.