Who Invented the Light Bulb? It Wasn't Just Edison

To assess just how much credit Edison deserves for 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. If Volta's name sounds familiar, it may be because the electrical measurement "volt" is named after him.

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 was extremely bright and 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.

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 be trapped in the glass bulbs. This unwanted gas could interfere with the filament and make producing light more difficult.

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. Edison also 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 were operated under the name Edison Electric Illuminating Company. The company was later purchased by Consolidated Gas and is now a utility company 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," explains Friedel. "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 said to be 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 pioneered by Humphry Davy 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 embrace of inventions.

The light bulb and the electric lamp were not the inventions of a single person. Rather, they were created in 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.

The continuing evolution endures to this day, as fluorescent lamps and LED lighting technology dominate the marketplace, while incandescent bulbs pioneered by Edison and Swan fall by the wayside. 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.

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!'"