Abstract
The so-called fourth book of Aristotle's Meteorologica is not about meteorological phenomena at all. It describes the formation out of the four elements of ‘homoeomerous’ substances, by which are meant minerals such as stones and metals, and organic substances like flesh, skin, and hair, and the changes they can undergo under the influence of heat, cold, and moisture. Most commentators, ancient and modern, have seen that it has very little to do with the first three books of the Meteorologica to which it is attached, and Alexander suggested that it should be placed after the second book de Generation et Corruptione