A self-made man – inventor and innovator – the tough, no-nonsense Thomas Alva Edison was a symbol of the age of enterprise in America. He scorned the stuffy older ways of thinking, famously dismissing Latin, Greek and Philosophy as “ninny stuff,” and spent his life creating inventions designed to bring ease and comfort into people’s homes – for a handsome profit.
With 1093 invention patents to his name – almost twice as much as anyone else in American history – Edison (and his employees) did more than anyone else to create a range of products that are now central to modern life. Here are 5 of Edison’s most famous inventions.
1. The Light Bulb (1879)
Arguably Edison’s most famous invention, the incandescent light bulb was patented in 1879. Scientists had been racing to create artificial light for years, yet it was the Ohio-born inventor who cinched the win by creating an incandescent bulb with a carbon filament that could be practically reproduced on a mass scale.
In his first public demonstration of the new light bulb, which took place at Edison’s Menlo Park, New Jersey laboratory on New Year’s Eve, 1879, Edison showed how the light bulb created light when electrical current passed through the metal filament wire, heating it to a high temperature until it glowed. More importantly, the hot filament was protected from the air by a glass bulb that was filled up with inert gas.
Edison was able to spend so much time on this invention because, thanks to his reputation as a successful inventor, he had the support of some leading financiers of the day. J.P. Morgan and the Vanderbilt family established the Edison Light Company and advanced Edison $30,000 for research and development.
2. The Phonograph (1877)
On 21 November, 1877, Edison was officially credited with inventing the phonograph – a revolutionary device which could record and play back sounds. This invention was greeted with hysteria at the time, so utterly extraordinary was the idea that we could preserve the spoken word, and its legacy has transformed every aspect of our modern world.
Edison first thought about the phonograph whilst working on two other world-changing 19th century inventions – the telephone and the telegraph. The technology used for the two, he decided, could also be altered to record sound – something which had hitherto never even been considered as a possibility.
In 1877, he began to create a machine designed for this purpose with two needles, one for recording the sound, and one for playing it back. The first needle would indent the sound vibrations onto a cylinder covered with tin foil, while the other one would copy the exact indentations to produce the same sound again.
When he spoke the oddly chosen words “Mary had a little lamb” into the machine, he was awed and astonished to hear them played back to him. Or, perhaps, he was the first of millions of people to dislike the sound of his own voice on recording.
3. The Kinetograph / Motion Picture Camera (1891)
In the late 1880s, Edison supervised his lab’s development of a technology “that does for the eye what the phonograph does for the ear.” Seeking to provide a visual accompaniment to the phonograph, Edison commissioned William Kennedy-Laurie Dickson, one of his young laboratory assistants, to invent a motion-picture camera in 1888 (possibly because of his background as a photographer).
Dickson combined the two final essentials of motion-picture recording and viewing technology. A device, adapted from the escapement mechanism of a clock, to ensure the regular motion of the film strip through the camera and a regularly perforated celluloid film strip to ensure precise synchronization between the film strip and the shutter.
There has been some argument about how much Edison himself contributed to the invention of the motion picture camera. While Edison seems to have conceived the idea and initiated the experiments, Dickson apparently performed the bulk of the experimentation, leading most modern scholars to assign Dickson with the major credit for turning the concept into a practical reality. The Edison laboratory, though, worked as a collaborative organization.
Movies became a big industry and Edison’s camera and viewer were quickly replaced by innovations such as the Lumière Cinématographe, a combination camera, printer and projector that allowed audiences to watch a film together. But Edison adjusted and his company became a thriving early movie studio, churning out scores of silent films between the 1890s and 1918, when it shut down production.
4. The Alkaline Battery (1906)
As one of the leaders of the electricity revolution, Edison patented the Alkaline Battery on July 31, 1906. In the early twentieth century, the available lead acid rechargeable batteries were notoriously inneficient and the acid battery market was already tied up by other companies. Hence, Edison pursued using alkaline instead of acid.
He had his lab work on many types of materials (going through some 10,000 combinations), eventually settling on a nickel-iron combination.
Edison obtained a US and European patent for his nickel–iron battery in 1901 and founded the Edison Storage Battery Company and by 1904 it had 450 people working there. The first rechargeable batteries they produced were for electric cars, but there were many defects with customers complaining about the product.
5. The Carbon Microphone (1878)
The first ever microphone that enabled voice telephony and amplification was the Carbon Microphone (then called the “carbon transmitter”), another one of Thomas Edison’s famous inventions.
He had begun work to improve the transmitters in 1876 by developing a microphone that used a button of carbon, changing the resistance with the pressure of sound waves. This would serve as a massive improvement on the existing microphones developed by Johann Philipp Reis and Alexander Graham Bell, which worked by generating an extremely weak electric current.
Edison’s work in this field was concurrent with Emile Berliner’s loose-contact carbon transmitter (who lost a later patent case against Edison over the carbon transmitters invention) and David Edward Hughes’ study and published paper on the physics of loose-contact carbon transmitters (work that Hughes did not bother to patent).
The carbon microphone is the direct prototype of today’s microphones and was critical in the development of telephony, broadcasting and the recording industries. Carbon microphones were widely used in telephones from 1890 until the 1980s.