the carbon microphone concept in 1877 to create an improved telephone for Western Union. In 1886, Edison found a way to improve a Bell Telephone microphone, one that used loose-contact ground carbon, with his discovery that it worked far better if the carbon was roasted. This type was put in use in 1890 and was used in all telephones along with the Bell receiver until the 1980s. Electric light In 1878, Edison began working on a system of electrical illumination, something he hoped could compete with gas and oil-based lighting. He began by tackling the problem of creating a long-lasting incandescent lamp, something that would be needed for indoor use. However, Thomas Edison did not invent the light bulb. In 1840, British scientist Warren de la Rue developed an efficient light bulb using a coiled platinum filament but the high cost of platinum kept the bulb from becoming a commercial success. Many other inventors had also devised incandescent lamps, including Alessandro Volta's demonstration of a glowing wire in 1800 and inventions by Henry Woodward and Mathew Evans. Others who developed early and commercially impractical incandescent electric lamps included Humphry Davy, James Bowman Lindsay, Moses G. Farmer, William E. Sawyer, Joseph Swan, and Heinrich Göbel. These early bulbs all had flaws such as an extremely short life and requiring a high electric current to operate which made them difficult to apply on a large scale commercially. In his first attempts to solve these problems, Edison tried using a filament made of cardboard, carbonized with compressed lampblack. This burnt out too quickly to provide lasting light. He then experimented with different grasses and canes such as hemp, and palmetto, before settling on bamboo as the best filament. Edison continued trying to improve this design and on November 4, 1879, filed for U.S. patent 223,898 (granted on January 27, 1880) for an electric lamp using "a carbon filament or strip coiled and connected to platina contact wires". The patent described several ways of creating the carbon filament including "cotton and linen thread, wood splints, papers coiled in various ways". It was not until several months after the patent was granted that Edison and his team discovered that a carbonized bamboo filament could last over 1,200 hours. In 1878, Edison formed the Edison Electric Light Company in New York City with several financiers, including J. P. Morgan, Spencer Trask, and the members of the