Powering the Dream_ The History and Promise of Green Technology - Alexis Madrigal [31]
Inside the clock, a wondrous operation occurred each minute: “the pneumatic distribution of time.”3 A burst of air raised a tiny vertically oriented bellows. The rod atop the bellows tripped a lever and the lever engaged with a sixty-tooth wheel that moved exactly one tooth.4 The wheel’s movement took the minute hand of the clock with it, so the sum of all those steps was to make one minute become the next at more than 7,500 machines across the city.5
The bursts of air that set this mechanical ballet into motion traveled across the city in pipes hung from the roofs of the city’s sewer mains from a building in east Paris on Rue St. Fargeau. Enterprising Parisians soon found that many other kinds of machinery could be run through the system—not to mention an entire early letter transmission system.6 A metering system developed that allowed customers to be charged for the amount of air they consumed. Usage exploded across the city in the 1880s.
In 1890 a London engineering professor found more than 225 compressed air motors scattered across the city ranging in size from half a horsepower to fifty horsepower. Figaro, Petit Journal, and other publications used compressed air for printing. All kinds of artisans were on the network, too:
They are also used in the workshops of carpenters, joiners, and cabinet-makers, of smiths, of umbrella-makers, of collar-makers, of bookbinders, and naturally in a great many places where sewing-machines are used, both by dressmakers, tailors, and shoemakers, and from the smallest to the largest scale. They find application also in all sorts of industrial work, with confectioners, coffee-roasters, color-grinders, billiard-ball makers, in many departments of textile industry and other matters too numerous to mention.7
What had been a tiny operation in 1870 had become a big business by 1892. A large central power plant was built in an iron-and-glass building marked by its two brick chimneys on the banks of the Seine.8 Inside the high-arched building, coal boilers powered twelve 2,000-horsepower air compressors. For every horsepower hour delivered at the end of the line, 3.3 pounds of coal had to be burned. Victor Popp, the Viennese inventor who devised the system, noted with pride that this fuel efficiency “is under all conditions superior to the best results obtained by electrical power transmission.”9 Indeed, even in 1900 power plants required 67,000 British thermal units of coal to generate a horsepower hour of electricity. That’s at least seven pounds of coal.10
Compressed air was seen as a legitimate competitor for electricity for the transmission of power. In 1890 there were no long-distance power lines in use, but the entire city of Paris was undergirded with compressed air transmission lines. Popp’s success gave tinkerers all over the world a new component for their dreams. Electricity, after all, had been used primarily for illumination, not industrial power. Induction motors—now two-thirds of those in use—had just been invented by Nikola Tesla, but they were not fine tuned. Electricity was not yet the universal power, and many people were still kind of frightened of it.
Meanwhile, compressed air could be used by almost anyone for almost anything. The same London engineer went to a roller coaster park and “found a large horizontal engine placed in a recess driving a dynamo and cells for the electric lighting of the whole building; a small vertical engine in another place worked the rotary pump, which actuated the ‘cascade;’ two or three large air-driven fans in wooden shafts served for ventilation; and lastly, a simple connection on a flexible pipe threw the air-pressure into beer-barrels as they were brought in.” Thus, compressed air could seemingly do just about anything.11
The success of the technology and the hearty willingness of the people of the time to project improvements made compressed air a hot topic. In early 1891 the engineers