This began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman.

Edison developed a system of electric-power generation and distribution Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan.

His staff was generally told to carry out his directions in conducting research, and he drove them hard to produce results.

William Joseph Hammer, a consulting electrical engineer, started working for Edison and began his duties as a laboratory assistant in December 1879.

The quadruplex telegraph was Edison's first big financial success, and Menlo Park became the first institution set up with the specific purpose of producing constant technological innovation and improvement.

Edison was legally attributed with most of the inventions produced there, though many employees carried out research and development under his direction.

Joseph Henry, president of the National Academy of Sciences and one of the most renowned electrical scientists in the US, described Edison as "the most ingenious inventor in this country... Edison's major innovation was the establishment of an industrial research lab in 1876.