This piece is part of the Sidewalk Talk series "15 Innovations That Shaped the Modern City."
The best way to appreciate the power of electric light isn't to stand on a street corner in Las Vegas, Times Square, or Tokyo. Consider instead the view of Earth from space, bathed at night in a faint glow, pole to pole. The primary source of all that visible light? Cities. "The astonishing transformation of night---everywhere that humans dwell in any numbers on Earth, with rare exception---is one of the greatest technological achievements," says Robert Friedel, a University of Maryland professor who co-authored Edison's Electric Light: The Art of Invention. "The electric light reshaped profoundly the design of buildings, streetscapes, neighborhoods, and cities in general."
For centuries, the rich depended largely on the poor to light their city streets and doorsteps with oil lamps. Wealthy Romans relied on a "laternarius," typically a slave who was responsible for lighting and carrying lamps on the outside of villas. Well-to do Londoners later depended on "link boys" to carry a torch and walk pedestrians home at night. By the 19th century and the adoption of gas light technology, a profitable lighting industry finally emerged, with manufacturing facilities for gas and the equipment needed to illuminate cities in Europe, the United States, and beyond.
While American and English scientists worked for years on the possibilities of tapping into electricity and incandescence to provide a safer, less expensive lighting option than gas, Thomas Edison envisioned an electric revolution during the 1870s. He replaced gas plants with steam-driven electric generators and underground gas pipes with electrical conductors to carry current, eventually making gas light technology obsolete.
Edison and his researchers in Menlo Park, New Jersey, were the first to develop a long-lasting, commercially viable incandescent bulb reliant on a very thin filament, and later discovered that a bulb with a carbonized bamboo filament could last more than 1,200 hours. Edison also had the financial muscle to scale his ideas. He was backed by J.P. Morgan and members of the Vanderbilt family to form what would later become the General Electric Company.
Electric infrastructure came to the densest and wealthiest areas of large cities by 1880, and the technology spread over the next two decades to the cities with both the manufacturing capacity and financial capabilities to make electricity a reality. The electric light was common in U.S. cities and even smaller towns by the mid-1890s, but merrymakers still looked on in awe when electricity lit up the 1893 World's Fair in Chicago.
"What visitors adored was the sheer beauty of seeing so many lights ignited in one place, at one time," Erik Larson wrote in his 2003 nonfiction bestseller, *The Devil in the White City. *"It was like getting a sudden vision of Heaven."
The light bulb invited new possibilities for urban work and play, whether it was a graveyard shift in a Pennsylvania factory, a night out in the Big Apple, or the first Major League Baseball game under the lights. (In 1935, the Reds beat the Phillies 2-1 at Cincinnati's Crosley Field.) "The electric light literally added hours to urban public life every day," says Friedel, "with gigantic implications for commerce, manufacture, safety, and general public intercourse."
Over time it became much easier and safer to light textile factories and steel mills at all hours, ushering in 24-hour manufacturing. White-collar workers settled into new office buildings during the same era, and a revolution of modern skyscrapers followed in the 1930s. It was then that American architect Raymond Hood christened the term "Architecture of the Night"---an idea that architects were now tasked with how best to light skyscrapers from the outside, giving birth to the modern nighttime skyline.
Electrification also gave rise to perhaps the strongest symbol of middle-class urban life: the department store. No longer dependant on windows for natural light, retailers could expand their hours. Sears, Roebuck & Company, Macy's, and J.C. Penney enjoyed exponential growth in the 1920s and 1930s. In New York, the combination of building illumination, an electrical advertising boom, and a new lease on nightlife all gave birth to the the Great White Way, the epicenter of lighting excess in the 20th century, where revelers ushered in the New Year with the inaugural ball drop on December 31, 1907---a literal celebration of light.
Electric infrastructure lagged behind in poorer and especially rural areas for decades, but streetlights were standard in most cities by the 1930s and 1940s. By the dawn of World War II, auto engineers had mastered tri-beam headlamps for "country driving."
Keeping the lights on at all hours showed the one weakness of the early incandescent bulb: efficiency. Just 10 percent of the energy consumed produces light; the other 90 percent yields heat. Scientists tweaked the formula to improve efficiency and cut down costs, and by the late 1930s they had developed fluorescent lights three times more efficient than incandescents. The need to light U.S. plants around the clock during World War II led to the rapid adoption of fluorescent bulbs, which dominated the market for decades.
Japanese inventor Shuji Nakamura, who won the Nobel Prize for revolutionizing modern lighting with the LED bulb, has suggested that lighting will soon emerge with an entirely different field of engineering: high-speed communication. In recent years, Nakamura has predicted that Li-Fi, the burgeoning optical communications technology that makes use of light instead of radio waves to send data at speeds of 3.5Gbps or more, could be dramatically boosted by the use of laser diodes.
"The modulation speed of laser lighting is much faster than LED lighting, almost 1,000 times faster," Nakamura says. "So the Internet speed would become much, much faster." Other scientists agree. "In the future light bulbs will be mini-computers with memory, processing power and LiFi will connect them to their environment," explains University of Edinburg professor Harald Hass. " 'LiFi' will be the rail-track of the fourth industrial revolution."