It is no exaggeration to say that the incandescent light bulb changed human civilization. With the advent of light bulbs, people could suddenly work and recreate deep into the night without relying on open flame (and its attendant heat, smoke and inherent danger) to illuminate a room.
Yet some historians argue that it's far too reductive to attribute the invention to just Edison. They posit that Edison was the one who invented the light bulb, but it was simply one in a long string of similar inventions.
Others say that while Edison's electric light bulbs did stand out from their forebears, even more credit should go to British inventor Sir Joseph Wilson Swan, who worked on incandescent lamps at the same time and later partnered with Edison. And yet another set of historians argue that this revisionist history is an overcorrection, and Edison is the rightful inventor of the light bulb.
Precursors to Thomas Edison's Incandescent Light Bulb
To assess just how much credit Edison deserves for the incandescent light bulb design, we must examine the work of inventors who came before him.
At the turn of the 19th century, Italian inventor Alessandro Volta pioneered concepts in controlling an electrical current, culminating in his "voltaic pile," which effectively functioned as a battery. Volta's name may sound familiar because the electrical measurement “volt” bears his name.
The voltaic pile inspired British chemist Humphry Davy to design a battery of his own and use it to power an arc lamp. The arc lamp did in fact produce visible light contained in a bulb, and since it debuted in 1806, Davy's invention beat Edison's by over seven decades.
But Davy's arc lamp emitted an extremely bright light, was hard to control, required a great deal of electric current and did not last long enough for practical home usage. While it found some utility as an outdoor streetlight, the electric arc lamp could not function as a lighting fixture in the home.
James Bowman Lindsay and Warren de la Rue
Chemists after Davy came to understand that the key to a sustainable incandescent lamp was choosing a filament that, when exposed to an electrical current, could continually glow without burning out. Scottish scientist James Bowman Lindsay introduced a copper-filament light bulb in 1835, while British scientist Warren de la Rue presented a platinum-filament bulb in 1840.
These light bulbs came well before Edison's, but they still lacked practicality. Lindsay's copper burned out too quickly, while de la Rue's platinum was too expensive, although platinum's high melting point provided a critical breakthrough.
These designs also suffered from poor vacuum tube technology, which meant that gas could end up trapped in the glass bulbs. This unwanted gas could interfere with the filament and make producing light more difficult.
Edison's Breakthrough to the Practical Light Bulb
Thomas Edison was the inventor who finally cracked the code of a truly practical light bulb, but this only came after years of experimentation. Working in a company he called the Edison Electric Light Company, Edison developed a high-resistance cotton filament, which burned for over 14 hours in a test. It also consumed far less electricity than competing designs.
Additionally, Edison benefited from the Sprengel air pump, invented in 1877, which greatly improved vacuum pump technology and allowed manufacturers to suck outside gasses out of a glass bulb. This, combined with the high electrical resistance of cotton, allowed filaments to burn far longer. Edison filed for his first patent in 1879, and the U.S. Patent Office granted it in January 1880. Edison would go on to found the Edison Illuminating Company.
Note that Edison Illuminating Company was never part of General Electric, another company Edison founded. Rather, Edison Illuminating Company created the first electrical generating stations in America, which operated under the name Edison Electric Illuminating Company. Consolidated Gas later purchased the company, now called Consolidated Edison, or ConEd.
Robert Friedel, professor emeritus of history at the University of Maryland-College Park, submits it was Edison's emphasis on practicality and real-world usage that won him his status in the history of the light bulb. "Edison's was the first truly practical electric light for general use, and this is exactly what its inventor set out to make," Friedel explains.
"He carefully identified all of the key qualifications for a successful rival to the alternatives ... reliability, longevity, economy and aesthetics. He deliberately set out to create an electric light that would check all these boxes — this is something no one else succeeded in doing."
Edison was one of several 1870s inventors working furiously to crack the code of sustainable incandescent lighting. American-British inventor Hiram Maxim tried to patent a light bulb at nearly the same time as Edison, but Maxim's patent was not granted by the U.S. Patent Office until July 1880.
Harold H. Schobert, professor emeritus at Penn State University and author of "Energy and Society: An Introduction," recalls: "I used to tell my class that Maxim was so infuriated by this that he went home and invented the machine gun." Schobert emphasizes this was a joke, but indeed Maxim's machine gun is another invention with vast societal impact.
Beyond Edison, the Englishman Joseph Swan may be the inventor with the greatest claim to inventing a practical light bulb. Swan focused on electric lamps that could emit light via carbonized paper filaments.
Swan received a British patent for an incandescent bulb in November 1880. His bulb went into wider practical use than Edison's. He lit the entire Savoy Theater of London using his invention. His own private home was reportedly the first to be fully lit by electric lighting.
Edison sued Swan in British courts for patent infringement. The courts ruled in favor of Swan, and to settle the dispute, the two men merged their businesses into a British company called Ediswan. They dominated the English market. Some of their bulbs have survived deep into the 21st century.
When it comes to Edison's famous rivals, many minds turn to the Serbian-American inventor Nikola Tesla, who spent several months employed at the Edison Machine Works in New York City.
No one would claim Tesla invented the light bulb, but during his brief tenure, Tesla submitted designs for arc lighting, the kind of street lighting that Humphry Davy pioneered decades before. Edison's own low-voltage design couldn't scale up to high-powered arc lighting.
For disputed reasons, Edison's company never put Tesla's designs into production, and Tesla bitterly left the company soon after — for reasons that may have had more to do with money than the embrace of inventions.
So Who Really Invented Light Bulbs?
The light bulb and the electric lamp were not the inventions of a single person. Rather, they are the results of a continual string of inventions, each building off work done by prior scientists. Edison's patent reflected what he had invented: not the first light bulb but rather the first electric light that had true mass application.
Patents protect past inventions, but Edison never shelved projects simply because someone else had gotten the idea before him. Schobert recalls: "My all-time favorite Edison story ... occurred when Edison was giving a group of visitors a tour of his Menlo Park laboratory. One of the visitors asked Edison what rules his staff had to follow when they were working on an invention. Supposedly Edison bellowed, 'We don't have rules around here! We're trying to accomplish something!'"
The Future of Lighting
The continuing evolution within the lighting industry endures to this day, as energy-efficient light bulbs and LED bulbs dominate the marketplace. As the incandescent bulbs that Edison and Swan fall by the wayside, there are also vintage-style LED Edison light bulbs that mimic the warm, yellow glow and filament design of the original.
The era of vacuum tubes and glass bulbs may be fading, but the goal remains to create the most practical, widely adopted light bulbs for the contemporary era. With energy efficiency becoming a priority, commonly used lights, such as compact fluorescent bulbs (CFLs), are also being phased out in favor of LED lighting under the Biden Administration.
This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.
Now That's Interesting
Thomas Edison lost most of his hearing as a child. It is now believed that a major cause was a bout with scarlet fever, along with recurring, untreated, middle ear infections.
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