Optical communication. Historical artwork of a system of communication using a series of torches to indicate letters of the alphabet. This system was described by the Ancient Greek scholar Polybius around 200BC. A system of ten torches and two walls were used to spell out words by their constituent letters according to a grid of coordinates. Two torches on the left and one on the right,as seen,might indicate the letter 'B'. From La Telegraphie Historique by Alexis Belloc (1888) | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Terry, Sheila |
Taille de l’image : | 4133 px × 2741 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |