in its mobility, sharpness, and ability to penetrate. He also said of air that its minuscule components are so smooth that one can barely feel them.

Plato's student Aristotle (384-322 BCE) developed a different explanation for the elements based on pairs of qualities. The four elements were arranged concentrically around the center of the universe to form the sublunary sphere. According to Aristotle, air is both hot and wet and occupies a place between fire