Meteorology. Although meteorology is now considered a subdivision of the earth sciences, to medieval scientists it was inextricably intertwined with the study of optics. Once again, the connection lies in the Aristotelian view of the world, for in his system both meteorology and optics take place in the sublunary region above the earth. Their natural place was within the spheres of air and fire, which lie above those of earth and water. Thus, the study of rainbows fell under both meteorology and optics, as did investigations of comets, shooting stars, the aurora borealis, and optical "illusions" such as the apparent change in the size of the Moon when it is at the horizon and the change in color of the Sun at dawn and dusk. The medieval scholars Albertus Magnus, Roger Bacon, Witelo, and Theodoric of Freiberg were the first to...