Pocket telegraph device. 19th-century artwork of a small magnet and connecting wires in a portable container. This apparatus is designed to be used to converse with operators when testing a telegraph line. This artwork is from 'History,Theory,and Practice of the Electric Telegraph' (1860) by US telegraph engineer George Bartlett Prescott (1830-1894) | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / King's College London |
Taille de l’image : | 4504 px × 3908 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |