Clepsydra

Use in the book

The demonstration has two complementary parts. In the first, the girl sets the pipe’s passage against her hand and lowers the vessel into water. Water does not enter because the air already inside opposes it. Once the obstruction is released, air gives way and an appropriate amount of water enters. The second begins with water in the vessel. With the passage closed by the hand, external air helps hold the water in place at the lower opening; release allows air inward and water outward.

The actions are simple enough to visualize, but the explanation is not trivial. Air is treated as a space-occupying mass capable of excluding water, and the human hand changes the available routes. The comparison makes the unseen constituent effective through visible outcomes. It is therefore a physical argument carried by an ordinary manipulation of an object, not just an ornamental simile.

The child or girl also matters to the presentation. The verse depicts play, allowing a domestic and familiar activity to carry a serious explanatory burden. The repeated bodily language of neck, gates, passage, and flesh then brings vessel and organism into close relation without claiming they are identical structures.

At the end the analogy returns to blood. As blood withdraws into the body’s interior, aither enters; as blood rises again, breath goes out. The vessel’s water corresponds functionally to the moving bodily liquid, but the text should not be forced into a one-to-one match for every part. It does not identify a particular bone as the vessel’s bronze or a particular organ as the girl’s hand.

The result is an account of alternating admission and exclusion. Calling the object a water-clock would distract from the action actually described: no measurement of elapsed time occurs in the passage. Whatever the broader range of uses of such vessels, this one is introduced to show how closing and opening a route changes the relation of air and water.

Places to read

1. B 100.8–15A girl plays with the bronze vessel; the first sequence excludes and then admits water.
2. B 100.16–21The reverse sequence retains and then releases water.
3. B 100.22–252The analogy returns to the blood-and-aither alternation in the body.

Translation in this edition

“Water-catcher” is a context-sensitive rendering. “Water-clock” is a common modern association with the Greek name but would imply a function absent from this fragment. The edition’s “girl” draws a human figure from the surrounding grammar; the noun παῖς itself is the brief introduction to the demonstrator.

Use in the book

At the close of the account of respiration, Aëtius says that Empedocles recalls what happens with the clepsydra. The placement connects the device with reciprocal displacement of blood and air: the behaviour of accessible materials offers a comparison for processes within a living body. Yet the testimony does not itself narrate a demonstration, identify the operator, or specify the apertures. The edition directs the reader to B100 for the fuller poetic account. That contextual link is valuable, but the verse should not be treated as quoted in this A-number. The same distinction applies to claims of experimental priority. An analogy or demonstrative device can have explanatory force without this single sentence establishing the world's first controlled experiment.

Places to read

1. A 74 (testimony)Aëtius, final sentence. Recalls the clepsydra immediately after explaining reciprocal movements of blood and air.
2. A 74 (apparatus)Modern editorial commentary. Links the brief reference to the longer verse passage B100.

Translation in this edition

“Water-clock” may suggest a time-measuring function more strongly than the physiological comparison requires. The local witness supplies a device-name and cross-reference, not enough details to build a unique apparatus.