The Beginnings: Pressurized Air and Patents
Although pneumatic tubes in their physical form were not invented until the late 1800s, the idea that pressurized air could be used to propel objects through empty vessels has been explored since antiquity. One of the earliest instances of such research occurred in Ancient Greece, when Hero of Alexandria completed his treatise on pneumatics. Exactly when "The Pneumatics" (or "Pneumatica") of Hero of Alexandria was published is still up for debate, though most scholars agree that he lived in the first century BC. Regardless, Hero of Alexandria’s "Pneumatica" assumed that “…air is matter. The air when set in motion becomes wind, (for wind is nothing else but air in motion)” (Hero of Alexandria 2). He found that “if from the application of force of the particles of air be divided and a vacuum be produced larger than is natural, the particles unite again afterwards; for bodies will have a rapid motion through a vacuum, where there is nothing to obstruct or repel them, until they are in contact” (Hero of Alexandria 3). In other words, air is excessively dense yet its particles are extremely flexible; when it is compressed, it will fall into empty spaces from the pressure exerted upon its particles. This creates a “vacuum” which, as Hero of Alexandria explores in his book, can put objects and machines in motion by the force of air.
While none of the nineteenth-century patents or articles dealing with pneumatic tubes cite Hero of Alexandria’s treatise, one can infer that his research informed the workings of this dead medium over one thousand years later. In a way, the pneumatic tube is a remediation of Hero of Alexandria’s early pneumatic devices. But even though we can trace pneumatics into antiquity, the actual “invention” of the pneumatic tube has a history that is complicated and confusing. The pneumatic tube’s invention cannot be traced back to a sole “inventor,” but rather a baffling hodge-podge of patents and improvements. This surge of innovation speaks to the moment of mass invention and production associated with the late 1800s and the Industrial Revolution; there are literally hundreds of patents involving pneumatic tubes between 1870 and 1900 alone.
Despite this puzzling array of information, one man is credited with “inventing” the pneumatic tube that coiled itself ‘round the world: Albert Brisbane. An American from New York City, Brisbane patented the “Improved Pneumatic Tube for Transporting Goods” (U.S. Patent No. 91513; Dated June 22, 1869). The language of this patent makes it plain that he did not invent this technology, but instead made vast improvements upon the original, which consisted of an oddly shaped “rectangular pneumatic tube or box, containing a hollow cylinder, running on rails, for the transportation of mails and merchandise” (U.S. Patent No. 91513). It is no wonder, then, why several newspapers at the time accredited Brisbane with inventing the pneumatic tube – he essentially remediated a rectangular box with rails into a pragmatic “round pneumatic tube, containing a hollow sphere or ball” for transporting goods (U.S. Patent No. 91513).
From the perspective of media archaeology, one can sense that this remediation had strong economic motivations. Basic physics reveals that a spherical object sent down a round tube will create less friction than a cylinder sent down a rectangular “tube” on rails. Time is clearly of the essence here; this technology would have been utterly useless had it not been extremely timesaving. Additionally, Brisbane’s patent addresses preventing air leakage by narrowing the sides of the hollow spheres, further emphasizing timesaving strategies. Less air leakage meant more air pressure applied to a narrower space, pushing the object down at much quicker speeds. And of course, one cannot forget the strongest economic motivation in improving a medium: money. Brisbane’s patent goes the extra mile by making suggestions for the “cheapest” structure of his pneumatic tube.
Pneumatic Mail in Europe
The "Tubes Pneumatique" of Paris date as far back as 1867. The first tubes connected the Bourse or stock exchange and the Grand Hotel beginning what would become an enormous system several hundred miles in tubes (Scientific American 1884). Like the system used in America, the tube is filled with compressed air in a partial vacuum. Instead of using air pumps or any engines, the Parisian system worked using power from the city's reservoir. Originally there were three large connected iron plated vessels that could hold 1,200 gallons each. The first vessel was filled with water, which was pushed into the other two vessels, which were filled with air. The air becomes compressed and once a valve was opened the air escaped rushing with force into the tubes (London Engineer).
The height of pneumatic post in Paris was in the 1930's where a letter, which the French called a "pneu" could get anywhere in the city in about an hour. 240 miles of tubing, just a few meters under the ground, created the net like system that laid just underneath Paris, carrying letter at an average speed of 40 m.p.h. After World War II the system was expanded and modernized but eventually began to decline and the Parisian pneumatic postal system ended in 1984 (Vincour).
The Prague pneumatic post was completed in 1899 with 60 kilometers that could transport letter, documents, and small parcel at 30 m.p.h. Prague's pneumatic post is the only working historical model left in the world. Today not much has changed except the number of parcel sent which use to number in the millions each year and now has dwindled into thousands every month. The post employs fifteen people altogether¬– nine workers and six dispatchers. Incoming parcels are indicated by a blinking red light and outgoing parcels by a green light. Every parcel must make a stop on Jindrisska street as the network is star shaped (Drake). Pneumatic postal networks are so much like highways, it is no wonder the word 'pneu' is also the French word for car tire.
"The Pneumatic Telegraph Lines of Paris." Scientific American (1845-1908); Dec13, 1884: Vol.LI, No. 24; APS Online pg. 395
London Engineer. "The Pneumatic Dispatch Tube in Paris." New York Observer and Chronicle (1833-1912); May 16, 1867; 45, 20; APS Online pg. 157.
Vinocur, John. "Paris Pneumatique is Now a Dead Letter." The New York Times, March 31, 1984, Saturday, Late City Final Edition, Section 1; Page 29, Column 2; Style Desk, 723 words.
Drake, James. "A Relic That Hasn't Gone Down the Tubes." Business Week, October 8, 2001, Business Week International Editions; Letter From Prague; Number 3752; Pg. 4, 1435 words.