Reading The Development of the Lightbulb Thomas Edison is generally credited with the invention of the light- bulb. In fact. he was just one inventor among many involved in the process of moving the concept of incandescent light from inspiration to marketable reality. What he actually invented in 1879 was a carbon fil- ament that lasted for forty hours. In 1880, he improved his idea, pro- ducing a filament derived from bamboo that burned for 1 ,200 hours. The first person to successfully produce light with electricity was Humphry Davy, who connected a carbon filament to a battery in 1809. Other inventors worked on refinements of this idea. In 1 835, James Lindsay unveiled an electric lamp, which cast enough light to read a book one and a half feet away. In 1854, Henrich Globel created the first actual lightbulb-a glass bulb containing a filament that glowed when electrical c·urrent passed through it. However, it burned out too quickly to have any commercial value. Then, Hermann Sprengel developed the Sprengel Pump, a device that used mercury to create a vacuum. Reduc- ing the oxygen in the bulb allowed the filament to glow longer before burning out. In 1 874, Henry Woodward and Matthew Evans fikd a patent for a light specifically described as "a shaped piece of carbon held between two electrodes enclosed in a glass vessel." Woodward and Evans attempted to raise the necessary money to improve and market their invention: however, as entrepreneurs. they had little success fmding anyone to back them fmancially. Eventually they sold the rights to their patents to Thomas Edison. Edison had already been working on the same idea, but for him money was not a critical issue. He was no longer a solitary inventor working in his basement, but the head of a laboratory with the support of investors. He worked to refme the Woodward and Evans light because its filament bumed out too quickly. Edison set about testing every material possible for use as a filament. "Before I got through," Edison recalled, "I tested no fewer than 6,000 vegetable growths, and ransacked the world for the most suitable filament material." He even considered using tungsten, which is the material currently used. Eventually, Edison tried a carbonized cotton thread filament clan1ped to platinum wires. When tested, it lasted forty hours. In 1880, he received a patent for this invention. By the end of the year, Edison had perfected a sixteen-watt bulb that lasted for 1 ,500 hours. At the same time, Sir Joseph Swan was working on similar ideas in England. In 1860, he obtained a patent for a carbon filament incandes- cent lamp, and in 1 878, another for an improved version of his lightbulb. 282 UNIT 1 0: TECHNOLOGY /INVENTIONS He presented it in a public lecture in 1879. In 1882. Swan sued Edison for patent infringement. As part of the settlement, Edison had to take Swan as a partner in his Brttish electric works. Also, in 1 877 and 1878, William Edward Sawyer and Albon Man were granted patPnts for electric lamps. Based on these patents, the U.S. Patent Office ruled in 1883 that Edison's patents were nvalid. Edison fought to appeal that ruling, and in 1 889, the court determined that his patents were indeed valid. Edison is famous for having said, "Genius is one percent inspiration and ninety-nine percent perspiration." It is an understandable state- ment coming from someone whose laboratory tested more than 6,000 fil- ament possibilities. Nevertheless, one might also consider the adage .. History is wrttten by the winners." Edison may not have been the actual inventor of the lightbulb, but he was the man who had the genius, the business sense, and the financial backing to invent the first one that was commercially viable. Answer the questions about The Development of the Lightbulb. Questions 1-5 �mplete the summary using the list of words below. In the 1800s, many !. . . . . . . . . . ... experimented with using electrical 2 . . . . . . ... . to produce light. James Lindsay 3 ... . ...... . . his version of an electric light in 1 835. It was brtght enough for reading a book. Henrich Globel developed the first lightbulb in 1854. His 4 . . . . . . . . . . . . , unfortu- nately, did not have commercial value. It needed 5 . ..... . ..... because it burned out very quickly. backers clamped current device Hled inventors refinement unveiled