Optical Telegraphs: An Early Internet

They installed a semaphore line across the Great Belt strait, Storeb�ltstelegrafen, between islands Funen and Zealand with stations at Nyborg on Funen, on the small island Sprog� in the middle of the strait, and at Kors�r on Zealand. Terry Pratchett’s Discworld novels, starting with The Fifth Elephant, (pub 1999) onwards, feature a widespread system of eight-shutter semaphore towers, known as Clacks, (= Fax) which occupy a similar role to that of the Internet. The French only began to replace semaphores with electric telegraphy in 1846, carry on using their optical telegraphs until the 1850s.

Source: www.douglas-self.com