Electrical telegraph
device · 1837 · Industrial Revolution
Sending messages as electrical signals over wires (Schilling, Cooke and Wheatstone, Morse).
What it is made of
- Copper wire — has part. Communication lines.
- Electromagnet — has part. Morse’s receiver.
- Relay — has part. Relays boosted the signal on long lines.
Principles and materials it uses
- Electromagnetism — uses. A telegraph receiver is an electromagnet that attracts an armature.
- Morse code — uses. Morse encoding.
- Copper — is made of. The wires are copper and iron.
Where it is used
- Time zones — is used in. Synchronizing time by telegraph.
- Weather forecast — is used in. Collecting reports by telegraph.
History: what it evolved from and what it influenced
- Telephone — evolved into. The telephone grew out of attempts to send several signals over telegraph lines (the “harmonic telegraph”).
- Phonograph — inspired. Edison came to the phonograph while working on recording telegraph and telephone signals.
- Optical telegraph — evolved from. The electrical telegraph replaced semaphore lines.
What it is a kind of
- Means of communication — is a kind of. A means of sending messages.
- Transatlantic cable — includes. A telegraph line.
Things built in a similar way
- Packet switching — works like. An analogy: telegraph messages were passed from station to station with intermediate storage — a “store and forward” principle similar to packet transmission.
- Email — works like. An instant text message over a network — like a telegram.
- SMS — works like. A short text message is the heir of the telegram.