You don’t need a mobile phone to send instant messages. This is an optical telegraph, and it can send 220 different messages. It was used during the Napoleonic Wars, in the early 19th century. There were telegraphs like this all along the coast, making it possible to send important messages from station to station. A little like Chinese whispers – but without the misunderstandings and laughter. Each of these telegraphs was several metres high.
Codebook
In order to send a message via an optical telegraph, you had to look up what number to use in a codebook. The code was supposed to be secret, but it didn’t stay secret for long, and soon everyone knew what the various numbers stood for. The much-feared message “4” meant “Enemy ships on the horizon”. The codebook is hanging on the telegraph, if you want to take a look. Could you send the message “Those ships are Danish”?
Chosen by Malin Elisabeth Johansen, History student