Frozen air

Use in the book

Lactantius at A51 skeptically attributes frozen air to Empedocles’ heaven. Aëtius’ companion account makes the heaven air compacted by fire in a crystalline way, while Achilles refers more generally to the frozen. The scholion on Basil specifies water instead, a difference that the edition’s claim of complete agreement should not conceal.

The moon receives related descriptions. Ps.-Plutarch at A30 says air cut off by fire congeals like hail. Aëtius at A60 calls lunar matter compacted, cloud-like air congealed by fire and therefore mixed; Plutarch records objections to a hail-like freezing of air enclosed by a sphere of fire. The combination of fire and freezing may strike a modern reader as paradoxical, but the ancient descriptions associate fire with consolidation of other material rather than providing a modern thermodynamic recipe.

A69’s account of lithification through heat offers a contextual parallel: the loss of moisture can leave solid matter. It is not proof that the moon and rocks are made by an identical mechanism. No numerical proportions or comprehensive physical process are supplied for lunar air.

Places to read

1. A 51 (testimony)Lactantius, De opificio dei; Aëtius II 11,2. Preserves frozen or fire-compacted air as the material of heaven, with Lactantius expressing skepticism.
2. A 30 (testimony)Ps.-Plutarch, Stromateis, in Eusebius P.E. I 8,10. Explains lunar formation by air cut off by fire and congealed like hail.
3. A 60 (testimony)Aëtius; Plutarch, On the Face in the Moon. Describes compacted lunar air and the hail-like air-body criticized by Plutarch.
4. A 69 (testimony)Pseudo-Aristotle, Problems. Provides a separate example of heat associated with consolidation through loss of moisture.

Translation in this edition

Heaven and moon are different objects, even when described through related freezing imagery. The accounts do not identify lunar matter with modern ice, and repeated reports need not be independent.