Pneumatic tubes. Historical artwork of a pneumatic messaging system at the Paris Post Office, France, in the 19th century. The tubes seen here are the start and end of a network of tubes along which messages are propelled by air differentials. This air differential is created using air compressors and a system of valves (operated using the wheels seen here). Speeds of around 40 kilometres an hour were possible. Pneumatic systems were first built to transmit telegraph messages to stock exchanges (London, 1853). The Paris system started in 1866, and covered most of the city by 1884. The system was closed in 1984. From La Telegraphie Historique (Alexis Belloc, 1888).