Hourglass neck und incandescent light bulb: was sie gemeinsam haben
- Schritt 1. Hourglass neck — ist Teil von — Hourglass. A narrow neck sets the rate.
- Schritt 2. Hourglass — funktioniert wie — Water clock (clepsydra). The same principle of timing by outflow, with sand instead of water.
- Schritt 3. Water clock (clepsydra) — ist hergestellt aus — Stone. The clepsydra from Karnak is a stone vessel.
- Schritt 4. Stone — ist Material für — Oil lamp. The first lamps were stone bowls (Lascaux).
- Schritt 5. Oil lamp — entwickelte sich zu — Incandescent light bulb. The electric lamp replaced oil and gas lamps.