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How to email a cat

How to email a cat

Pneumatic tubes were once a vital part of communications networks in London, New York and Paris, says Tom Standage

Pneumatic tubes were once a vital part of communications networks in London, New York and Paris, says Tom Standage

Tom Standage | June/July 2018

In 2006 Ted Stevens, a senator from Alaska, inadvertently coined a phrase when he cluelessly described the internet as “a series of tubes”. The internet is made up of many things – wires, optical fibres, servers, switches and routers – but tubes are not among them. Yet there was a time when communications networks really did rely on tubes. Messages written on paper whizzed along underground pipes, propelled by compressed air from steam engines. This steampunk internet has been largely forgotten but its origins shed light on the ways that rapid digital communication can create problems as well as solutions.

The first pneumatic-tube system was set up in London in 1854 to carry telegrams between the Central Telegraph Office (CTO) and the stock exchange, just 220 yards away. At the time around half of all telegrams received at the CTO related to stock trades. As the volume of incoming traffic increased, the connection to the stock exchange became overloaded, and time-sensitive telegrams started to pile up. It became apparent that it would be quicker to transport the messages in physical form rather than retransmit them electrically over such a short distance. Josiah Latimer Clark, an engineer at the Electric Telegraph Company, devised a novel way to do it.

An underground tube, an inch and a half in diameter, was laid along the route. Five messages at a time could be packed into a leather-coated cylinder with a felt bumper at the front. The carrier was then fired along the tube at 20 feet per second using compressed air from a six-horse-power steam engine. This increased the capacity of the network link tenfold, allowing ten messages to be sent each minute. In 1858 the system was upgraded with larger tubes that had a greater capacity and then expanded across London. While the network largely carried stock trades and business documents, it was also used for personal correspondence for people who could afford the expense. In the 1860s similar networks were built in Liverpool, Birmingham and Manchester. The idea quickly spread abroad: pneumatic-tube networks were soon operating in Paris, Berlin, Vienna, Prague, Rome, Naples and Milan.

One of the most elaborate versions was built in New York, linking several post offices in Manhattan and Brooklyn. With tubes eight inches in diameter, it could handle small parcels. At its inauguration in 1897, a tortoise-shell cat was sent from the south end of Broadway to Park Row, nearly a mile uptown. The cat was dazed, but otherwise unharmed. Paris developed the most extensive network – it opened in 1879 and was capable of delivering a message anywhere in the city within two hours. Sending a “pneu” involved filling in a pre-paid form and handing it in at a post office, or posting it into a mailbox on the back of a tram. The missive would soon wing its way through the pneumatic-tube network to the post office nearest the recipient.

Pneumatic tubes are still used to carry order slips in some libraries, to move cash out of tills in large shops, and to transport blood samples in hospitals. But improvements in communications technology, and the use of vehicles to carry mail, meant tubes were no longer needed to send messages. They had largely died out by the mid-20th century, though the Paris system remained in operation until 1984.

Pneumatic tubes carried information in physical form, because it was quicker than electronic transmission over short distances. Today, by contrast, many things that used to be sent in physical form (such as books, music and movies) can be delivered more quickly as data. But when it comes to interpersonal communication, sending texts or emails is now so cheap and easy that messages pile up, and the speed of the network becomes irrelevant: the limiting factor is our human inability to cope with the incoming deluge. As a result, there are still times when the best way to get through is to walk over to a colleague’s desk to get a quick answer, or send someone a hand-written note. The story of the pneumatic tube reminds us that the occasional need to step from the digital back into the physical realm is as old as digital networks themselves.