Elon Musk is not the first inventor to put his hopes into vacuums. Respect to the Hyperloop, but pneumatic tubes have a centuries-long history -- in both human infrastructure and in the minds of people who dream it up.
Below, a brief history of the pneumatic tube, in theory and in practice.
Otto von Guericke's Magdeburg Hemispheres, 1660s
Working in the 17th century, the German scientist Otto von Guericke constructed the world's first artificial vacuum. He demonstrated his invention using a contraption known as the "Magdeburg hemispheres": two large, copper hemispheres with rims that fit tightly together. When the rims were sealed, air was pumped out of the interiors. In an innovation that would lead to the pneumatic tube, Guericke was able to demonstrate that the air-less hemispheres could be held together by the air pressure of the surrounding atmosphere.
The Atmospheric Railway, 1830s
The atmospheric railway took advantage of Guericke's demonstration, relying on air pressure to provide its power for propulsion. In 1799, the inventor George Medhurst proposed the idea that goods could be moved pneumatically through cast-iron pipes; in 1812, he expanded the idea to include passenger carriages.
The Beach Pneumatic Subway, 1860s-1870s
In the 1860s, the American inventor Alfred Ely Beach began proposing an underground rapid transit system to ease New York City of its above-ground traffic congestion. Beach modeled his design after London's underground Metropolitan Railway; his vision differed, however, in that Beach's proposed trains would be propelled by pneumatics instead of steam engines.
The idea, despite opposition from prominent property owners (John Jacob Astor among them), passed through bills in the New York State legislature in 1871 and 1872; those bills were ultimately vetoed by the state's governor, however, on the grounds that an underground, pneumatic subway wouldn't be able to offer enough compensation -- to the city or to the state.
The Crystal Palace Pneumatic Railway
Also known as the Crystal Palace atmospheric railway, the train was constructed near Crystal Palace Park in South London in the mid-1860s. The train's propulsion power was provided by an enormous fan -- a fan some 22 feet in diameter -- which was in turn powered by a steam engine. On return journeys, the fan was reversed to create a vacuum that would suck the carriage backwards.
The Prague pneumatic post, 1889-present
The Prague pneumatic post, established in 1889, is is the world's last preserved municipal pneumatic post system. It's a system of metal tubes underneath the city center of Prague -- tubes totaling some 34 milies in length. Though it was rendered inoperative by floods in 2002, its current owner, Telefónica O2 Czech Republic, is gradually repairing the system. In fact, as our own Alexis Madrigal detailed in his book, many European cities had similar setups. The Viennese inventor Victor Popp created a system for Paris that was so successful that investors in the Niagara Falls power project seriously considered using pneumatic tubes -- not the nascent technology of long-distance AC transmission -- to deliver the power of the falls.
Robert Goddard's New York-to-San Francisco Vacuum Train, 1910s
The American rocket pioneer Robert Goddard didn't confine his ideas to the air: He also had a plan for making a train that would go from Boston to New York in 12 minutes flat. His idea? Float the train on magnets inside a specially-built tunnel with all the air pumped out; that would eliminate the friction that normally slows a train down. Goddard's vacuum railway was, of course, never built.
As Communications at NASA
NASA is just like any office: Before computers were widespread for intra-office communication, pneumatic tubes did the trick. In the image below -- NASA Mission Control Center during the Apollo 13 mission -- you can see pneumatic tube canisters in the console to the right.
Pneumatic Tubes Used at Drive-Through Banks, 1900s
Yep, these still exist.
ET3's Elevated Tube, 2000s
The closest sibling to Musk's Hyperloop is probably ET3's Elevated Tube. The design features car-sized passenger capsules traveling in tubes of 5 feet in diameter on a frictionless maglev. Airlocks at passenger stations, the company says, allow for the transfer of capsules without admitting air. Linear electric motors accelerate the capsules, which then coast through the vacuum for the remainder of the trip using no additional power.
The name pretty much says it all. The Foodtubes Project, a consortium of academics, project planners, and engineers, wants to mimic the networked infrastructure of the Internet for pneumatic-tube-aided food delivery. The Internet as a series of tubes ... full of food.
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