Lawrence Sperry Lawrence Sperry Lawrence Burst Sperry (21 December 1892, Chicago, Illinois, United States – December 13, 1923, English Channel) was an aviation pioneer. He was the third son of the gyrocompass co-inventor, Elmer Ambrose Sperry and his wife Zula. Sperry invented the first autopilot, which he demonstrated with startling success in France in 1914. Sperry is also credited with developing the artificial horizon still used on most aircraft in the early 21st century. On 13 December 1923 Sperry took off amid fog in a Verville-Sperry M-1 Messenger from the United Kingdom headed for France but never reached his destination. His body
Invention of the telephone receiver. Gray did not convert his caveat into a patent application until after the caveat had expired and hence left the field open to Bell. When Gray applied for a patent for the variable resistance telephone transmitter, the Patent Office determined "while Gray was undoubtedly the first to conceive of and disclose the (variable resistance) invention, as in his caveat of 14 February 1876, his failure to take any action amounting to completion until others had demonstrated the utility of the invention deprives him of the right to have it considered." The carbon microphone was independently developed around 1878 by