Megaphone communications. 19th-century illustration of a large sets of megaphones being used to communicate with an airship. The amplification of the soldier's voice has enabled communication over a distance of some four kilometres. This illustration is from 'Physique Populaire' (Emile Desbeaux, 1891). | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library |
Bildgröße: | 3358 px × 5205 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |