Beginnings The use of
electrical telegraphy in Paris rose rapidly in the period of the
Second French Empire, from 17 stations in 1851 to 2,200 in 1867. The telegraph lines became overloaded and the operating companies had to resort to sending messages by
carriage between the two major telegraph stations on the Rue de Grenelle and the Place de la Bourse, with messages sometimes delayed by road traffic. As early as 1853 a pneumatic tube message system was installed by
Josiah Latimer Clark to link the
London Stock Exchange with the offices of the
Electric Telegraph Company. Tests of a pneumatic message-carrying system were made by
Ambroise Ador in Paris'
Parc Monceau in 1852 and further tests were made by in 1854. In December 1866 the first line of a
pneumatic messaging service was installed between the offices of the
Central Télégraphique in Rue Feydeau and
Le Grand Hotel in
Boulevard des Capucines, a distance of . The messages were carried in containers within a steel tube of diameter, buried below ground. Messages from hotel guests were transported through the long tube to the telegraph office from where they could be transmitted onwards. The air was compressed not by motorised means but by the pressure of head of water held in reservoirs. A pressure of was capable of being generated, which allowed a cylinder long and carrying 40 messages to be transmitted in 60–80 seconds. A reservoir at either end of the line allowed for messages to be sent in both directions. The Grand Hotel line was extended in 1867 to form a six station "hexagon" incorporating the telegraph offices at the Place de la Bourse and Rue de Grenelle. The other stations on the route were at the Place du Théâtre-Français, Rue des Saints-Pères and Rue Boissy-d'Anglas. In the following decades additional polygonal circuits were added to the original hexagon, doubling it in size by 1872 – though the circuits remained within the area of the
Wall of the Ferme générale.
Opening to the public On 5 February 1879 the
Ministry of Posts and Telegraphs was formed bringing together the two services, previously under the control of the
Ministry of Finance and
Ministry of the Interior respectively. The Ministry opened the use of the network to the public from 1 May that year. Officially messages sent on the pneumatic network were considered to be telegrams. However, unlike telegrams the speed of transmission was not affected by the length of the message. In addition the cost to the user was not linked to length, except that each message had to be written on
pre-franked forms, while telegrams were charged per word. The pneumatic message forms were known as "petits bleus" (small blues) for their size and colour. The forms were posted in small boxes attached to
post boxes, left at telegraph counters or in special boxes at the rear of trams (which were emptied at the tram terminals). The network would carry the message to the station closest to the recipient from where it would be delivered by courier. The couriers, some as young as 14, delivered the messages by foot and cycle with mopeds being used from 1930. To pass between pneumatic networks the message was taken from its container, time stamped and inserted into the next tube. It was therefore possible to determine the route each message had taken by examining the time stamps. Coverage was extended to parts of Seine and
Seine-et-Oise in 1907 without extending the pneumatic network. Cycle couriers carried the messages to these suburbs from the existing stations.
Modernisation The pneumatic network was extended to the suburbs for the first and only time in 1914 when an extension was made to Neuilly. Louis Gaillard, a recent graduate of the
École Nationale Supérieure des Télécommunications, was placed in charge of the workshops in 1932. A few months later he was placed in charge of the entire network, a position he held until 1974. He became a driving force for the modernisation of the network. He ensured the continuation of the electrification programme, which completed in 1942 with the electrification of the Hôtel des Postes station. At completion the network had motors totalling , of which around would be applied at any one time with the remaining units in reserve or maintenance. The original metal tubes were gradually replaced by
PVC from 1965. This reduced the vulnerability of the network to oxidation and offered less resistance to the message containers, reducing noise. By 1970 there were of PVC tubes in service. The closure followed the introduction of two new services by the ministry: Postéclair, a public fax system, and Postexpress, a rapid parcel delivery network in Paris. Most employees of the pneumatic post were redeployed into Postexpress. == Government network ==