Fifteen years later, in 1875, Swan returned to consider the problem of the light bulb with the aid of a better vacuum and a carbonised 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. Starting that 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 Light Company, and started commercial production.
In America Edison had been working on copies of the original Swan patent, 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.
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 fibers. His newly established Swan Electric Company, which by merger was to become the Edison and Swan United Company, used the cellulose filaments, that Swan had invented, in their bulbs.
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 General Electric, and that company then shifted to cellulose.
In 1886 Ediswan moved production to a former jute mill at Ponders End, North London. In 1916 Ediswan set up Britain's first radio thermionic valve factory at Ponders End. This area, with nearby Brimsdown subsequently developed as a centre for the manufacture of valves, cathode ray tubes, etc. and nearby parts of Enfield became an important centre of the electronics industry for much of the 20th century.
Ediswan became part of British Thomson-Houston and AEI in the late 1920s.
-submitted by Paul Green