Communication tower. Historical artwork of a Roman communication tower with a lit torch. This was a form of optical telegraphy that used smoke signals by day,and torchlight by night. Successive towers could be used to transmit a signal across long distances. This drawing was based on a carving on Trajan's column in Rome. Trajan's column was constructed from AD106-113 and depicts the conquests of Emperor Trajan. From La Telegraphie Historique by Alexis Belloc (1888) | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Terry, Sheila |
Taille de l’image : | 3307 px × 3902 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |