As I clicked into Google today, I could not fail to notice that they are celebrating Thomas Edison’s 164th Birthday. You can see the image here, its chock full of many things that he invented such as the light bulb and other devices.
So I followed some links and did a bit of reading, and as a result made a rather surprising discovery – Edison did not invent the light bulb – well perhaps you knew, and I’m the only one. After being surprised like this, I did a quick straw poll asking “Who invented the light bulk?”. The answer from all was, “Edison”.
Now what really surprised me is that while he did not invent it, he claimed that he did, but if it was not him, then who?. It was apparently a chap called Joseph Swan.
In 1850 Swan began working on a light bulb using carbonized paper filaments in an evacuated glass bulb. By 1860 he was able to demonstrate a working device, and obtained a British patent covering a partial vacuum, carbon filament incandescent lamp. Fifteen years later, in 1875, Swan returned to consider the problem of the light bulb with the aid of a better vacuum and a carbonized thread as a filament. The most significant feature of Swan’s improved lamp was that there was little residual oxygen in the vacuum tube to ignite the filament, thus allowing the filament to glow almost white-hot without catching fire. However, his filament had low resistance, thus needing heavy copper wires to supply it.
Swan received a British patent for his device in 1878, about a year before Thomas Edison. Swan had reported success to the Newcastle Chemical Society and at a lecture at Sunderland Technical College in February 1879 he demonstrated a working lamp. Swan turned his attention to producing a better carbon filament and the means of attaching its ends. He devised a method of treating cotton to produce ‘parchmentised thread’ and obtained British Patent 4933 in 1880. From this year he began installing light bulbs in homes and landmarks in England. His house Underhill on Kells Lane in Low Fell, Gateshead was the first in the world to have working light bulbs installed. In 1881 he had started his own company, The Swan Electric Lamp Company, and started commercial production.
So where then does Edison fit in?
In America, Edison had been working on copies of the original light bulb patented by Swan, trying to make them more efficient. Though Swan had beaten him to this goal, Edison obtained patents in America for a fairly direct copy of the Swan light, and started an advertising campaign which claimed that he was the real inventor. Swan, who was less interested in making money from the invention, agreed that Edison could sell the lights in America while he retained the rights in Britain.
Ah but then things get even more interesting.
While searching for a better filament for his light bulb, Swan inadvertently made another advance. In 1881, Swan developed and patented a process for squeezing nitro-cellulose through holes to form conducting fibres.
So did Swan and Edison go head-to-head? Nope, they did what was in the best interests of each and merged. In 1883 the Edison & Swan United Electric Light Company was established. Known commonly as “Ediswan”, the company sold lamps made with a cellulose filament that Swan had invented in 1881. Variations of the cellulose filament became an industry standard, except with the Edison Company. Edison continued using bamboo filaments until the 1892 merger that created Edison General Electric, and that company then shifted to cellulose.
Now don’t get the wrong end of the stick here. Edison did invent a heck of a lot of other cool things, in fact he is one of the most prolific inventors in history and had over 1000 patents in his name for items that include a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures, so he fully deserves his place in history … but not for inventing the light bulb, that was Swan.
(This was all new to me, I knew none of this before I woke up today)