Hourglass. This device uses the calibrated falling of sand from an upper chamber to a lower chamber to track the passage of time | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Llewelyn-Davies, Patrick |
Bildgröße: | 3928 px × 4961 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |