In New York City in 1869, as a supervisor in a stock-ticker firm, he made improvements on the stock-ticker. Later he opened his own laboratory in Newark, N.J., where he made important improvements in telegraphy and on the typewriter, and invented the carbon transmitter that made Alexander Bell's telephone practical.

In 1876 he moved his laboratory to Menlo Park, N.J., where he invented the first phonograph and the prototype of the incandescent electric light bulb.

Being interested in systems for distributing electric power from central generating stations he formed his own company which later merged with another company to become General Electric Co.

By the time he died he had accumulated an impressive list of 1093 patents (motion picture inventions; electricity applications; light bulb; electric typewriter development; dictaphone; mimeograph; etc), but Thomas Edison's most important contribution was that he organized systematic research on a very large scale with hundreds of people working together.