Edison's major innovation was the first industrial research lab, which was built in Menlo Park, New Jersey. It was built with the funds from the sale of Edison's quadruplex telegraph. After his demonstration of the telegraph, Edison was not sure that his original plan to sell it for $4,000 to $5,000 was right, so he asked Western Union to make a bid. He was surprised to hear them offer $10,000, which he gratefully accepted. 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 work under his direction. His staff was generally told to carry out his directions in conducting research, and he drove them hard to produce results. The large research group included engineers and other workers.