October 22 - Edison's light bulb

On October 22, 1879, Thomas Edison successfully tested the first commercially practical electric incandescent light bulb. To conduct current and create light inside the bulb, he used a filament of carbon, which he had tried previously along with platinum and other metals in many experiments since 1878. The bulb lasted 13.5 hours. Edison did not invent the first electric light bulb. He had been preceded by numerous other inventors, particularly Joseph Swan, a British physicist and chemist who had made early attempts in the 1860s and later lit homes and a London theater with light bulbs. However, Edison overcame key shortcomings that included short life and high cost. He made further improvements on the bulb, filed for a patent in November, and formed the Edison Electric Light Co. in New York with investors that included J. P. Morgan. At the first public demonstration of his incandescent light bulb on December 31, 1879, in Menlo Park, NJ, Edison commented, "We will make electricity so cheap that only the rich will burn candles."