Early electric telegraph machine. 1868 illustration of an early telegraph machine that used two magnetic needles (top). Swiss physicist Georges-Louis Le Sage invented the first telegraph machine in 1774. However, although his system worked, it was impractical and not adopted. Practical electric telegraphy was invented in 1837. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Collection Abecasis |
Bildgröße: | 2664 px × 3626 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |